Dispiroacridine-indacenobisthiophenes positional isomers: Impact of the bridge on the physicochemical properties

In the emerging technologies of organic electronics, positional isomerism has appeared in recent years as an efficient molecular tool to tune the electronic and physical properties of organic semi-con­­ductors (OSCs), which are at the heart of the devices. For example, modifying the position of the linkages (ortho, meta, para), allows to extend or restrict the π-con­jugation between two molecular fragments and, all the key electronic parameters of an OSC can be easily modified (HOMO / LUMO energy levels, single and triplet state energies, charge carriers mobilities…) leading to substantial different performances in electronic devices.

The indacenobisthiophene (IDT) fragment, which is an association of two thienyl cores to a central phe­nyl ring, has appeared in the last ten years as an important building unit to construct efficient or­ganic materials mainly for organic photovoltaics but also for Organic Field-Effect Transistors (OFETs). However, with a few exceptions, nearly all the IDT-based molecules described to date in the literature are cons­tructed on a central para-linked phenyl ring with the two thienyl sulfur atoms in an anti-configuration (see para-IDT core in pink in Chart 1). Re­cent­ly, the study of IDT positional isomers possessing a central meta-linked phenyl unit with the two sulfur atoms in a syn configuration (see meta-IDT core in blue in Chart 1) has allowed to show the impact of positional isomerism on this family of compounds.

Continuing this systematic approach, the authors investigate herein the incorporation of the widely known electron rich phe­nyl­­acridine (PA) fragment spiro-linked to the meta- or para-IDT core. Thus, Di­Spiro­Phe­nyl­A­cri­dine-IDT isomers, para-DSPA-IDT and meta-DSPA-IDT, constructed on the so-called “3π-2spiro” ar­chi­te­ctu­re, have been investigated through a detailed structure-properties relationship study.

Chart 1. Positional isomers investigated (para-DSPA-IDT and meta-DSPA-IDT)

In the present work, the group of Prof Cyril Poriel and Prof Joëlle Rault-Berthelot (Institut des Sciences Chimiques de Rennes- UMR 6226, Rennes) reports that the phenylacridine fragment significantly modifies the elec­tronic, physical and charge transport properties compared to structurally related DiSpiro­Fluo­­re­ne-IDT analogues (para-DSF-IDT, meta-DSF-IDT). This finding is different to what was reported in literature for other couples of IDT-based isomers and shows the key role played by the spiro-connected frag­ments on the charge transport properties of these molecular systems and open new avenues for meta-substituted oligomers.

Despite that the properties are mainly driven by the IDT core, this work shows that the bridges (herein spiro-connected phenylacridine) allow a fine tuning of all the properties. Particularly, the electrochemical studies have revealed the strong differences observed in the oxidation of the two isomers.

Figure 1. Left, CVs of para-DSPA-IDT (1.5 × 10-3 M) and of meta-DSPA-IDT (2.15 × 10-3 M) recorded between 0.25 and 1.8 V, sweep-rate 100 mV.s-1. Right: DPVs normalized on the first oxidation wave for para-DSPA-IDT and on the second oxidation wave for meta-DSPA-IDT. Pulse Height: 25 mV, sweep-rate 50 mV.s-1, t: 50 ms. Working platinum disk electrode (Ø 1 mm).

This work also shows that the mobilities of charge carriers are higher for the meta isomer than for the para isomer. This finding is different to what was reported in literature for other couples of IDT-based isomers and shows the key role played by the spiro-connected frag­ments on the charge transport properties of these molecular systems.

Figure 2. Thickness-scaled current-voltage characteristic of the para and meta-DSPA-IDT and para and meta-DSF-IDT hole-only SCLC devices (Left), SCLC mobility and SCLC device (right). In left, the dotted lines indicate the SCLC regime and the continuous ones the Ohmic regime.

BIOGRAPHICAL INFORMATIONS

Cyril Poriel received his PhD in 2003 from the University of Rennes 1. After a postdoctoral stay at the University of Exeter (UK), he joined the CNRS (Institut des Sciences Chimiques de Rennes) in 2005, where he is currently CNRS Research Director. His main research interest deals with the design of π-conjugated architectures for Organic Electronics. He is author/co-author of more than 120 publications, reviews and book chapters.

Joëlle Rault-Berthelot received her PhD in 1986 from the University of Rennes 1, where she is currently CNRS research director (Institut des Sciences Chimiques de Rennes). She has been working for 40 years in electrochemistry. Since 2005, she is involved in the design of π-conjugated systems for Organic Electronics and is author/co-author of more than 160 publications, reviews and book chapters.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Amphiphilic-like carbon dots as antitumoral drug vehicles and phototherapeutical agents

Carbon dots (CDs) are nanosized carbon particles that have attracted the attention of researchers from different fields for their potential applications due to their high photostability, tunable excitation and emission, low toxicity and high biocompatibility. Reports on CDs that are soluble in non-aqueous solutions are still scarce, despite being recognized as promising materials and their compatibility with biological membranes facilitates their traversing. This feature is attractive for biomedical applications, in particular in cancer, where drug resistance and low specificity (i.e. side effects) urge the development of new drugs whose fate may be compromised by solubility, stability and clearance rate.

Recently the group of Prof. Santoyo and collaborators at Universidad of Granada (Spain) have demonstrated that the thermolysis of citric acid in DMSO and then reaction with alkyl amines yields CDs (LCDs) that bear both hydrophobic alkyl chains and carboxylic groups, and that the former make them suitable for hosting hydrophobic guests and the latter allow the modulation of their hydrosolubility. As a proof of concept the hydrophobic drug camptothecin (CPT) and the NIR fluorescent hydrophobic dye IR780 were assayed. The clinical implementation of both molecules is limited by their poor solubility, although CPT is a potent chemotherapeutic agent and IR786, besides the emission in the 807–823 nm wavelength range that makes it suitable for bioimaging, shows an absorption peak at 792 nm that yields a temperature increase and a production of ROS upon illumination with NIR light, enabling its use in photothermal and photodynamic therapies.

When LCD-2Na was loaded with CPT to yield LCD-2Na@CPT and the toxicity on a battery of cell lines was compared with an equivalent amount of free fresh CPT (Fig. 1), results demonstrated that the interaction between LCD-2Na and CPT is reversible and that the released drug is functional, despite it underwent a processing incompatible with the stability of free CPT.

Fig.1 Comparison of the cytotoxicity of LCD-2Na@CPT (green) and free CPT (red) on different cancer cell lines at different equivalent concentrations of CPT. Cell lines were incubated for 24 h with suitable amounts of either free CPT or LCD-2Na@CPT and cytotoxicity was assayed by the MTT method. Results are means ±1 standard deviation.

Additionally, the system LCD-2Na@IR780 was found to provoke an increase in the temperature of the solution up to 68℃ upon illumination with a 808 nm laser and yielded the formation of oxygen singlet with the concomitant destruction of IR780. At this point, it is important to recall that temperatures above 48℃ for minutes provoke irreversible injury that is enhanced by the reactive species produced during the destruction of IR780 by the laser.

Fig. 2 Temperature increase as a function of time of 200 μL of a water solutions containing 133 μM IR783 (red), 72 μM LCD-2Na@IR780 (blue) and 285 μM LCD-2Na@IR780 (magenta) irradiated with a 808 nm NIR laser at a power of 1.2 W cm−2 for 5 min (A) or 10 min (B). Inset B: Thermal image of the epperdorf containing the LCD-2Na@IR780 solution and the sample holder during the illumination. The temperature was recorded in real time with a high-resolution infrared camera.

It is important to highlight that LCDs are well tolerated by cells and, using a suitable length of the alkyl chains, they form inclusion complexes with hydrophobic guests of complementary size. The values of log P and the results obtained from the model molecules CPT and IR780 support the biotechnological potential of LCDs as drug carriers and in photothermal therapy.

Francisco Santoyo-Gonzalez is a Full Professor in Organic Chemistry at Universidad de Granada (Spain), full member of the Academy of Mathematics, Physical-Chemistry and Natural Sciences and  founder and leader of the group Glycochemistry & Bioconjugation. His research focuses on the development of new synthetic methodologies, with a particular emphasis in those related with the click-chemistry concept, and their application in a variety of diverse (bio)fields including cyclodextrins, glycochemistry, bioconjugation, non catalytic and catalytic hybrid-materials, nano-materials, targeted drug delivery, gene-transfection and (bio)sensors.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Enhance of an efficient sensitivity for the diclhovors detection by a low-weighted gelator based bolaamphiphile amino acid derivatives decorated with a hybrid graphene quantum dots/enzyme/ hydrogel

Supramolecular hydrogels arise from the self-assembly of low molecular weight gelators (LMWG) and a large amount of water (typically higher than 99% by mass) using non-covalent interactions.  Bolaamphiphilic molecules comprise of at least two parts including a hydrophobic skeleton such as alkyl chains, a steroid, or a porphyrin, and two hydrophilic groups on both ends which to give either symmetric or asymmetric end groups.  Such bolaamphiphiles with hydrophobic spacers can act as low molecular mass gelators.

Non-chemically crosslinked hydrogels have been extensively studied in the context of enzyme encapsulation and stabilization. However, a flexible and porous structure is required to facilitate full penetration of the enzyme into the substrate.  The immobilization of amphiphilic graphene quantum dots (GQDs) and enzymes into hydrogels remains of great interest for amplifying a signal to give high sensitivity for sensing applications and maintaining enzymatic activity in biological applications.

Graphene quantum dot nanozymes (GQDzymes) with peroxidase mimic catalytic activity for analytical and biomedical applications, for example of glucose, organophosphate detection, are of great interest.  Graphene quantum dots embedded within porous hydrogels exhibit useful physical properties. For instance, mediated through hydrogel encapsulation they show advantageous high fluorescent intensity compared to those in solution. This can result in high sensitivity for fluorescent sensing applications.

Recently, the groups of Boosayarat Tomapatanaget (Chulalongkorn University, Thailand) and Jonathan W. Steed (Durham University, UK) have collaborated to design novel fluorescent hybrid materials comprising graphene quantum dots and enzymes supported in Lphenylalanine derived bis(urea) supramolecular hydrogels (GQDs/Enz/Gels) for detection of organophosphates such as pesticides. Determination of organophosphates (OPs) using this hybrid material arises from the turn-on photoluminescent responses observed in the presence of the pesticide and is caused by inhibition of the enzymatic production of hydrogen peroxide, which quenches luminescence as shown in Scheme 1.

Scheme 1. Hybrid hydrogels of GQDs/Enz/Gels and proposed mechanism of organophosphate pesticide detection.

The enzyme-loaded photoluminescent sensing hybrid gel materials (GQD/Enz/Gel) were prepared in two stages (Figure 2, S1 – S2). The microstructures of materials were examined by SEM with the comparison of GQDs/Gels and GQDs/Enz/Gels with different gelation time. Moreover, the rheological properties of gels demonstrated large G¢ values by the addition of GQDs or by using phosphate buffer as the solvent. GQD/Enz/Gel materials have been investigated for their organophosphate sensing ability. Gratifyingly, the visual changes showed that the photoluminescence intensity of the GQDs/Enz/Gels depended on the concentration of organophosphate pesticide dichlorvos, which inhibited the activity of the acetylcholine esterase enzyme (AChE) in the hybrid hydrogels.  The inhibition efficiency of AChE by OPs in oxo-form of the phosphate group (methyl-paraoxon and dichlorvos) are higher than those of OPs in thio-form (malathion and parathion).  Interestingly, the naked-eye fluorescence images obtained by the GQDs/Enz/Gels with dichlorvos, under UV irradiation at 365 nm displayed a significant brightness change upon increasing the analyte concentration.

Figure 2. (A1) Preparation of partial GQDs/Gels (stage1) and GQDs/Enz/Gels hybrid hydrogels (stage2). (A2) SEM images of the dried partial gels (xerogels) from stage 1 prepared for 1 min and the hybrid hydrogels from stage 2 prepared for 30 min followed by drying under ambient conditions for 2 days. (B) frequency-sweep rheology of gelator 4b and GQDs/Gels from 4b in different conditions. (C1) visual changes of GQDs/Enz/Gels with various number of OPs and ACh. (C2) Comparison of inhibition efficiency (%) of AChE in hybrid hydrogels after incubation in 1.25 x10-6 and 12.5 x10-6 M of four organophosphate pesticides. (D) Photographs of hybrid GQDs/Enz/Gels sensory chips (Glass slide 7.6 x 2.6 cm and circle with diameter of 0.5 cm) in the presence of various concentration of dichlorvos (DV) and time of measurement.

This work also provides new insight into improving the performance of low molecular weight hybrid hydrogels through combination with GQDs, enzyme and phosphate buffer. The result is a highly effective and potentially versatile sensing system, with a high sensitivity and stability.  This is the candidate sensing system regarding to the enzymatic turn-on sensing in a small molecule gel medium. This efficient enzymatic sensing candidate offers opportunities for the development of a myriad of specific and highly sensitive hybrid nanomaterial-based (bio)sensors.

Prof. Jonathan W. Steed
University of Durham

Assoc. Prof. Boosayarat Tomapatanaget
Chulalongkorn University

Jonathan W. Steed obtained his B.Sc. and Ph.D. degrees at University College London, working with Derek Tocher on organometallic and coordination chemistry. He graduated in 1993 winning the Ramsay Medal for his Ph.D. work. Between 1993 and 1995 he was a NATO postdoctoral fellow at the University of Alabama and University of Missouri, working with Jerry Atwood. In 1995 he was appointed as a Lecturer at King’s College London. In 2004 he joined Durham University where he is currently Professor of Inorganic Chemistry. Professor Steed is co-author of the textbooks Supramolecular Chemistry (2000, 2009 & 2021) Core Concepts in Supramolecular Chemistry and Nanochemistry (2007) and around 350 research papers. He has edited various books including the 8-volume Supramolecular Chemistry from Molecules to Nanomaterials (2012). He is the recipient of a number of awards, most recently the 2021 RSC Tilden Prize. He is Editor-in-Chief of the American Chemical Society journal Crystal Growth & Design. His interests are in crystallization, supramolecular gels and crystalline solids particularly pharmaceutical solids, co-crystals and hydrates. See personal web pages for full details.

Boosayarat Tomapatanaget is associate professor in the Department of Chemistry, Faculty of Science, Chulalongkorn University (Thailand). She received her PhD in Chemistry at the Faculty of Science, Chulalongkorn University in 2003. The research field of Professor Boosayarat Tomapatanaget encompasses many aspects of supramolecular chemistry, particularly in applications such as the design and synthesis of chemosensors. The molecular recognition of biological targets has formed a major part of host-guest chemistry including the hybrid organic/inorganic based on nanomaterials for sensing purpose.

 

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Quinolinophenothiazine as Electron Rich Fragment for RGB Single-Layer Phosphorescent Organic Light-Emitting Diodes

The development of efficient organic host matrices for the emissive layer of Phosphorescent Organic Light-Emitting Diodes (PhOLEDs) is at the origin of the fantastic progresses made by this technology in the last twenty years. The role played by the host matrix is crucial as it should prevent energy back transfers from the guest emitter to the host and favour the confinement of excitons. The rational design of host materials for guest phosphors has allowed to reach very high-efficiency red, green and blue PhOLEDs (with external quantum efficiency EQE>25%). However, all these devices are multi-layer PhOLEDs, which are constituted of a stack of organic layers in order to improve the injection, transport and recombination of charges within the emissive layer. To reduce the cost and the environmental footprint of the OLED technology, simplifying the multi-layer structure is one interesting direction for the future. The so-called Single-Layer PhOLEDs (SL-PhOLEDs, Figure 1), the simplest device only made of the electrodes and the emissive layer, have thus stimulated a strong interest for the last fifteen years. However, high efficiency SL-PhOLEDs (especially for the blue emission) are very rarely reported in literature due to the difficulty to design an efficient host material. To reach high-performance SL-PhOLEDs, the host material should fulfil several precise criteria: (i) a high triplet state energy ET˃ 2.7 eV to confine the triplet excitons within phosphorescent guest, (ii) HOMO/LUMO energy levels well adapted to the electrode Fermi levels allowing efficient charge injection, (iii) good and well balanced mobilities of electrons and holes (ambipolar character) in order to compensate for the absence of electron/hole transporting layers, and (iv) thermal and morphological stabilities to extend the lifetime of the devicesThese four criteria can be fulfilled by the careful association of an electron-rich and an electron-deficient unit within a single molecule. 

Figure 1. Schematic representation of the architecture of a Single-Layer PhOLED (Left) and a Multi-Layer PhOLED (Right). Hole injection layer (HIL), hole transporting layer (HTL), electron injection layer (EIL), electron transporting layer (ETL), hole blocking layer (HBL), electron blocking layer (EBL), Emissive Layer (EML).

In the present work, the group of Prof Cyril Poriel (Institut des Sciences Chimiques de Rennes- UMR 6226, Rennes) reports a high-efficiency host material constructed on a barely studied electron rich fragment, namely quinolinophenothiazine (QPTZ). The QPTZ fragment is a phenylacridine bridged by a sulphur atom, Figure 2. Despite appealing properties induced by this bridging (e.g. strong electron rich character), this fragment remains almost unexplored to date in organic electronics. Herein, the strong potential of the QPTZ fragment as host for the new generation of simplified SL-PhOLEDs is demonstrated. Red, green and blue SL-PhOLEDs were successfully fabricated and yielded an average external quantum efficiency of ca 10% (Figure 3). High luminances of ca 10000 cd/m2 for red and blue devices and 40000 cd/m2 for green devices were obtained. These luminances are higher than the best reported to date with structurally related analogues and highlight the strong interest of the QPTZ fragment in such devices. Thanks to its high HOMO energy level, the QPTZ unit also allows to decrease the threshold voltage of the corresponding devices, which is a key point in ‘single-layer’ technology.

Figure 2. Phenylacridine and Quinolinophenothiazine molecular fragment

This work demonstrates the potential of the QPTZ fragment in the design of host materials for high performance single-layer PhOLEDs. QPTZ appears as a promising building unit and can advance the field of organic semi-conducting materials. We are convinced that the future development of QPTZ-based materials would also be appealing for other organic devices.

Figure 3. SL-PhOLEDs characteristics using SQPTZ-2,7-F(POPh2)2 as host material. A) Current density (mA/cm²) and luminance (cd/m²) as a function of the voltage; B) Current efficiency (cd/A, filled symbols) and power efficiency (lm/W, empty symbol) as a function of the current density (mA/cm²) and C) Normalized EL spectra.

BIOGRAPHICAL INFORMATIONS

Cyril Poriel received his PhD in 2003 from the University of Rennes 1. After a postdoctoral stay at the University of Exeter (UK), he joined the CNRS (Institut des Sciences Chimiques de Rennes) in 2005, where he is currently CNRS Research Director. His main research interest deals with the design of π-conjugated architectures for Organic Electronics. He is author/co-author of more than 120 publications, reviews and book chapters. twitter: @CyrilPoriel

 

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Silk fibroin microspheres as optical resonators for wide-range humidity sensing and biodegradable lasers

Silk fibroin (SF) is a biopolymer from Bombyx mori mulberry silkworm that has been utilized as textile for millennia. Recent advancement has emphasized to the biodegradation and biocompatibility of silk for medical applications. 

Due to the hydrogen bonding in silk fibroin, SF interacts with water molecules through the random coil conformation, while the β-sheet conformation provides mechanical strength to the entire spherical structure. 

Figure 1. Optical (a), fluorescence (b), and SEM (c) images of the SF microspheres. Scale bars: 5 µm. (d) PL spectra of a single SF microsphere upon excitation with cw laser (λex = 450 nm). Each WGM peak is assigned as shown on the bottom. (e) PL spectra of a single SF microsphere upon excitation with fs pulsed laser.

Recently, the group of Prof. Yohei Yamamoto and collaborators of University of Tsukuba have demonstrated that self-assembled SF microspheres, doped with ionic fluorescent dye, display resonant luminescence, which shifts in response to the humidity change. The resonant peaks result from the total internal reflection of the fluorescence, causing interference at the circumference of the microspheres. The SF microspheres display lasing property upon femto-second laser pumping (Figure 1).

The WGM peaks respond to the change of the ambient humidity. When the humidity is low, SF microsphere release water molecules, leading to shrinkage of the SF microsphere and thereby causing the WGM peaks shift to the lower wavelength. In the reversal process where ambient humidity is high, SF microsphere is hydrated, causing the shift WGM of the WGM peaks to the higher wavelength (Figure 2).

Figure 2. (a) Humidity-dependent PL spectra of a single SF microsphere upon excitation with cw laser (λex = 450 nm). (b) Plot of the wavelength of the resonant peak of TE26 upon increasing (filled circle) and decreasing (open circle) the surrounding humidity. (c) Plot of the wavelength of the resonant peak of TE26 upon 6 cycles of hydration (red) and dehydration (blue) between 93 and 25 %RH.

It is interesting to highlight the secondary structure of silk fibroin. Upon treated with alcohol, β-sheet conformation is increased, providing rigid structure for the SF microspheres while the remaining random coil structure in the SF microspheres is interacting with ambient moisture. This combination contributes to the SF microsphere for obtaining a high responsivity and high sensing range toward humidity.

These properties have given a new prospect or direction for designing next generation microresonators for optical sensing or lasing applications.

Prof. Yohei Yamamoto, University of Tsukuba

Yohei Yamamoto is a professor in the department of materials Science, faculty of Pure and applied sciences, University of Tsukuba. He received his doctor degree in 2003 from Osaka University. After post-doctoral researcher term, he was appointed as an associate professor in University of Tsukuba at 2010. on 2018, he promoted to full professor in University of Tsukuba. His research interests are self-assembly of π-conjugated molecules, polymers and biomolecules to construct electronically and optically active nano/micrometer-scale materials. He is the author of more than 90 articles and cited more than 2900 times with an index H = 28.

https://publons.com/researcher/1757952//

 

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Materials Chemistry Frontiers 2020 Best Paper Prizes

By .

Materials Chemistry Frontiers 2020 Best Paper Prizes

 

From this year onwards, we would like to introduce the Materials Chemistry Frontiers Best Paper prizes which recognize the most outstanding papers published in the journal. After a selection process involving the Associate Editors, Editorial and Advisory Board members, we have chosen to award not only a best paper but also a runner-up and a best review.

Best Paper

Cyclobutene based macrocycles

Pan Wang, Ruqiang Lu, Arthur France-Lanord, Yanming Wang, Jingjing Zhou, Jeffrey C. Grossman and Timothy M. Swager

Mater. Chem. Front., 2020,4, 3529-3538
https://doi.org/10.1039/D0QM00824A

Corresponding authors:

Timothy M. Swager is the John D. MacArthur Professor of Chemistry and the Director, Deshpande Center for Technological Innovation at the Massachusetts Institute of Technology. A native of Montana, he received a BS from Montana State University in 1983 and a Ph.D. from the California Institute of Technology in 1988.  After a postdoctoral appointment at MIT he was on the chemistry faculty at the University of Pennsylvania 1990-1996 and returned to MIT in 1996 as a Professor of Chemistry and served as the Head of Chemistry from 2005-2010.  He has published more than 500 peer-reviewed papers and more than 110 issued/pending patents. Swager’s honors include: Election to the National Academy of Sciences, an Honorary Doctorate from Montana State University, National Academy of Inventors Fellow, The Pauling Medal, The Lemelson-MIT Award for Invention and Innovation, Election to the American Academy of Arts and Sciences, The American Chemical Society Award for Creative Invention, The American Chemical Society Award in Polymer Chemistry, The Christopher Columbus Foundation Homeland Security Award, and The Carl S. Marvel Creative Polymer Chemistry Award (ACS).

Swager’s research interests are in design, synthesis, and study of organic-based electronic, sensory, energy harvesting, membrane, high-strength, liquid crystalline, and colloid materials.  His liquid crystal designs demonstrated shape complementarity to generate specific interactions between molecules and includes fundamental mechanisms for increasing liquid crystal order by a new mechanism referred to as minimization of free volume. Swager’s research in electronic polymers has been mainly directed at the demonstration of new conceptual approaches to the construction of sensory materials.  These methods are the basis of the FidoTM explosives detectors (FLIR Systems Inc), which have the highest sensitivity of any explosives sensor.   Other areas actively investigated by the Swager group include radicals for dynamic nuclear polarization, applications of nano-carbon materials, organic photovoltaic materials, polymer actuators, membranes, and luminescent molecular probes for medical diagnostics.  He has founded five companies (DyNuPol, Iptyx, PolyJoule, C¬2 Sense and Xibus Systems) and has served on a number of corporate and government boards.

ORCID: https://orcid.org/0000-0002-3577-0510

 

Jeffrey C. Grossman is the Department Head of Materials Science and Engineering at the Massachusetts Institute of Technology and the Morton and Claire Goulder and Family Professor in Environmental Systems. He received his PhD in theoretical physics from the University of Illinois and performed postdoctoral work at the University of California at Berkeley. He was a Lawrence Fellow at the Lawrence Livermore National Laboratory and returned to Berkeley as director of a Nanoscience Center and head of the Computational Nanoscience research group, with a focus on energy applications. In fall 2009, he joined MIT, where he has developed a research program known for its contributions to energy conversion, energy storage, membranes, and clean-water technologies. In recognition of his contributions to engineering education, Grossman was named an MIT MacVicar Faculty Fellow and received the Bose Award for Excellence in Teaching, in addition to being named a fellow of the American Physical Society. He has published more than 200 scientific papers, holds 17 current or pending U.S. patents, and recently co-founded a company to commercialize graphene-oxide membranes.

ORCID: https://orcid.org/0000-0003-1281-2359

 

Best Paper Runner-up

A polymorphic fluorescent material with strong solid state emission and multi-stimuli-responsive properties

Ji-Yu Zhu, Chun-Xiang Li, Peng-Zhong Chen, Zhiwei Ma, Bo Zou, Li-Ya Niu, Ganglong Cui and Qing-Zheng Yang

Mater. Chem. Front., 2020,4, 176-181
https://doi.org/10.1039/C9QM00518H

Corresponding authors:

Qing-Zheng Yang received his PhD in 2003 from the Technical Institute of Physics and Chemisty (TIPC), CAS. After completing postdoctoral research at the University Louis Pasteur and at the University of Illinois, Urbana, he returned to TIPC in 2009 as a full professor. He moved to Beijing Normal University in 2014, where he is a professor of chemistry. He received an APA Prize for Young Scientist from the Asian and Oceanian Photochemistry Association in 2013, Distinguished Young Scholar award from NSFC and Advanced Newton Fellowship from Royal Society in 2015. His research interests cover photochemistry of supramolecular assemblies, photodynamic therapy and fluorescent probes for bioimaging.

ORCID: https://orcid.org/0000-0002-9131-4907

 

Ganglong Cui got his B.S. degree in Chemistry from Beijing Normal University in 2004. He studied theoretical chemistry under the supervision of Prof. Wei-Hai Fang at Beijing Normal University and Prof. Weitao Yang at Duke University and earned his Ph.D. degree in Theoretical Chemistry in 2009. He continued his research as a postdoctoral associate with Prof. Weitao Yang at Duke University from 2010 to 2011 and as a Max-Planck and Alexander von Humboldt Scholars with Prof. Walter Thiel at Max-Planck-Institut für Kohlenforschung from 2011 to 2014. Then, he joined College of Chemistry in Beijing Normal University and the Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, and became a full professor in 2014. His present research interests are mainly focused on developing and applying accurate and efficient excited-state electronic structure and ab initio nonadiabatic and adiabatic dynamics methods for simulating photophysical and photochemical processes in complex chemical, biological, and materials systems. Until now he has published more than 130 SCI papers and has been invited to give scientific talks at many domestic and foreign conferences. He has been supported by the National High-Level Young Talents Project, the Outstanding Youth Fund of the National Natural Science Foundation of China, the Key R&D Project of the Ministry of Science and Technology, etc.

ORCID: https://orcid.org/0000-0002-9752-1659

 

 

Best Review

Advanced functional polymer materials

Kaojin Wang, Kamran Amin, Zesheng An, Zhengxu Cai, Hong Chen, Hongzheng Chen, Yuping Dong, Xiao Feng, Weiqiang Fu, Jiabao Gu, Yanchun Han, Doudou Hu, Rongrong Hu, Die Huang, Fei Huang, Feihe Huang, Yuzhang Huang, Jian Jin, Xin Jin, Qianqian Li, Tengfei Li, Zhen Li, Zhibo Li, Jiangang Liu, Jing Liu, Shiyong Liu, Huisheng Peng, Anjun Qin, Xin Qing, Youqing Shen, Jianbing Shi, Xuemei Sun, Bin Tong, Bo Wang, Hu Wang, Lixiang Wang, Shu Wang, Zhixiang Wei, Tao Xie, Chunye Xu, Huaping Xu, Zhi-Kang Xu, Bai Yang, Yanlei Yu, Xuan Zeng, Xiaowei Zhan, Guangzhao Zhang, Jie Zhang, Ming Qiu Zhang, Xian-Zheng Zhang, Xiao Zhang, Yi Zhang, Yuanyuan Zhang, Changsheng Zhao, Weifeng Zhao, Yongfeng Zhou, Zhuxian Zhou, Jintao Zhu, Xinyuan Zhu and Ben Zhong Tang

Mater. Chem. Front., 2020,4, 1803-1915
https://doi.org/10.1039/D0QM00025F

Corresponding author:

Ben Zhong Tang is professor in The Chinese University of Hong Kong, Shenzhen (CUHK-SZ), China. He is serving as Dean of the School of Science and Engineering at CUHK-SZ, Director of AIE Institute, and Dean of SCUT-HKUST Joint Research Institute. He received BS and PhD degrees from South China University of Technology and Kyoto University, respectively, and conducted postdoctoral research at University of Toronto. He joined HKUST as an assistant professor in 1994 and was promoted to chair professor in 2008. He was elected to Chinese Academy of Sciences (CAS), Royal Society of Chemistry (RSC), Asia Pacific Academy of Materials, and World Academy of Sciences for the Advancement of Science in Developing Countries in 2009, 2013, 2017 and 2020, respectively. His research interests include macromolecular chemistry, materials science, and biomedical theranostics. He has published over 1,600 papers which have been cited for over 119,000 times, with an h-index of 155. He has been selected as a Highly Cited Researcher in both areas of Chemistry and Materials Science by Web of Science since 2014. He has received the State Natural Science Award (1st Class; 2017) from the Chinese Government, the Scientific and Technological Progress Award from the Ho Leung Ho Lee Foundation (2017) and Senior Research Fellowship from the Croucher Foundation (2007).

Prof. Tang mainly engages in polymer chemistry and advanced functional materials research, especially in the field of chemistry and materials in the field of Aggregation-Induced Emission (AIE). He is the originator of AIE concept and the leader of AIE research. Personal Home Page: https://tangbz.ust.hk/tbz.html

ORCID: https://orcid.org/0000-0002-0293-964X

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Dual-Template Approach to Hierarchically Porous Polymer Membranes

By .

Polymer membranes are an important class of materials that find use in a wide variety of fields. The suitability of a polymer membrane often requires careful tuning of their properties to the target application. This must be balanced with the cost of any modification. Hence the non-solvent induced phase separation method (NIPS) is a common route of manufacture for polymer membranes, as it is easy to accomplish on a commercial scale at low-cost.’

In the NIPS method, the polymer of choice is first dissolved in a good solvent, along with any additives, before its immersion in a non-solvent to produce the membrane morphology. This morphology typically shows a dense skin-layer with smaller pores above a layer of larger finger-like vertical pores. By careful choice of additive, some of the membrane properties, including hydrophilicity and microstructure, can be modified.

Poly(ethersulfone) (PES) is a material commonly used for water filtration membranes, chosen for its good mechanical, thermal and chemical properties. Use of an amphiphilic surfactant additive has been shown to produce a membrane with a larger and more well-defined microstructure in the larger finger-like pore regime, as well as increasing the surface hydrophilicity, a key requirement for reduction in biological fouling.

This work by Southern and Evans of the University of Cambridge introduces an additional level of structural hierarchy by the use of a second template molecule, 4-(phenylazo)benzoic acid (PABA), as well as the surfactant Pluronic® F127 (F127) to allow templating of both the dense skin layer and the larger pores. This addition of PABA leads to a more fibrous structure at the 1μm level, leading to higher pore connectivity and permeability, compared to membranes templated only with F127 (Figure 1).

Figure 1a. shows the poor connectivity of the skin layer of a membrane templated with only F127, compared to the fibrous structure of a membrane templated with both F127 and PABA shown in Figure 1b.

Their work demonstrates that this fibrous structure leads to a remarkable increase in flow rate that is improved further by the subsequent removal of the PABA. Extraction using ethanol is shown to provide an excellent approach for removal. This extraction method also allows recycling of the PABA for further membrane manufacture.

This dual-template approach, as part of the NIPS process, can be used to easily modify membrane manufacture, producing membranes exhibiting a hierarchical structure with improved pore connectivity, which could find use as energy materials or in water filtration.

Authors:

Dr Rachel C. Evans

Dr Rachel Evans obtained her MChem and PhD in Physical Chemistry from Swansea University. She was a Marie Curie Postdoctoral Fellow at the Université Paris-Sud, France and subsequently held an FCT research fellowship between the University of Coimbra and the University of Aveiro, Portugal. From 2009-2016, she was an Assistant, then Associate Professor in Physical Chemistry at Trinity College Dublin (TCD). In 2017, Rachel moved back to the UK to take up a University Lectureship at the University of Cambridge in the Department of Materials Science and Metallurgy. Rachel’s research is multidisciplinary and involves polymer, colloid and photophysical chemistry. Her current work is focused on the development of photoactive polymer-hybrid materials for luminescent solar devices, organic photovoltaics and stimuli-responsive membranes. She is a Fellow of the Royal Society of Chemistry and the Institute of Materials, Minerals and Mining and. In 2017, she was awarded the Dillwyn Medal for STEMM from the Learned Society of Wales and the MacroGroup UK Young Researcher’s Medal.

Thomas Southern graduated from the University of Cambridge with an MSci and B.A. in Materials Science. In 2017, Thomas began his PhD as part of the Functional Photoactive Materials group at the Department of Materials Science and Metallurgy, within the University of Cambridge. Thomas’ work, funded by an EPSRC studentship, focuses on hierarchically porous membranes for environmental remediation.

Article information:

Dual-template approach to hierarchically porous polymer membranes
Thomas J. F. Southern and Rachel C. Evans
Mater. Chem. Front., 2021, Advance Article
https://doi.org/10.1039/D0QM00610F

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Shu-Hong Yu — introducing the new Editor-in-Chief of Materials Chemistry Frontiers

By .

We are delighted to announce the new Editor-in-Chief for Materials Chemistry Frontiers, Shu-Hong Yu from University of Science and Technology of China!

Shu-Hong Yu completed PhD in inorganic chemistry in 1998 from University of Science and Technology of China. From 1999 to 2001, he worked in Tokyo Institute of Technology as a Postdoctoral Fellow, and was awarded the AvH Fellowship (2001-2002) in the Max Planck Institute of Colloids and Interfaces, Germany. He was appointed as a full professor in 2002 and the Cheung Kong Professorship in 2006. He was elected as Academician of Chinese Academy of Sciences in 2019. He serves as the Director of the Division of Nanomaterials and Chemistry, Hefei National Laboratory for Physical Sciences at Microscale.

His research interests include bio-inspired synthesis of inorganic nanostructures, self-assembly of nanoscale building blocks, nanocomposites, their related properties and applications. His research work has been cited more than 56,400 citations (H index 132), named as a Highly Cited Researcher from 2014 to 2020.

It is an honour to serve as Editor-in-Chief of Materials Chemistry Frontiers. I look forward to working together with the Editorial Board to maintain the high-quality standards of our journal and to continue its success.

Read Shu-Hong’s latest review article in MCF on nanowire materials.

Shu-Hong will formally assume the role of Editor-in-Chief on 21st December 2020 from Professor Ben Zhong Tang, who has led the journal since launched. We would like to thank Ben Zhong for his years of hard work, dedication and diligence. MCF has maintained a rapid and steady growth on its scientific quality and global impact during the past four years. We are confident Shu-Hong will continue the many successes of MCF and keep enhancing the flourishing reputation of the journal under his leadership.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Materials Chemistry Frontiers Desktop Seminar: Celebrating Prof. Fred Wudl’ s 80th Birthday

By .

Materials Chemistry Frontiers is pleased to announce a Webinar Celebrating Prof. Fred Wudl’ s 80th Birthday. It will focus on the topic of organic semiconductors showcasing the latest work from Fred Wudl and his friends.

Register Now

https://rsc.zoom.us/webinar/register/WN_eTodlScqT-W8SugtlJUH2A

 

Schedule


11 December 2020, 9:30-12:00 am (UTC+8)

Time Talk title Speaker
9:30 – 9:35 Opening speech Dmitrii F. Perepichka (Chair)
9:35 – 10:20 Fifty Years of Fun with Organo-Sulfur Chemistry and Materials Science Fred Wudl
10:20 – 10:45 A Brief History of Conjugated Polyelectrolytes: In Honor of Prof. Fred Wudl Kirk Schanze
10:45 – 11:10 Conjugation Functional Organic and Polymeric Materials for OPV Yongsheng Chen
11:10 – 11:35 Non-Classical Thiophene-based Imide Materials as n-Type Semiconductors Hong Meng
11:35 – 12:00 Towards Higher Twisted Acenes and Azaacenes Qichun Zhang

 

Biography


Speakers:

Prof. Fred Wudl, University of California, Santa Barbara

Fred Wudl, Retired 2019, University of UCSB. B.S. 1964 and Ph.D. 1967, UCLA and postdoctoral, Harvard, 1968 to 1972 SUNY Buffalo, 1972 – 1982 Bell Laboratories, 1982 – 1997 UCSB, 1997 – 2006 UCLA, 2006 – 2019 UCSB. Discovered the electronic conductivity of the precursor to the first organic metal and superconductor. Research interests in conducting polymers. Currently interests in optical and electrooptical properties of processable conjugated polymers, organic chemistry of fullerenes, design and preparation of self-mending and self-healing materials and Li batteries. Received numerous and has published over 595 papers with 47,500 citations and H index of 100.

 

Prof. Kirk Schanze, University of Texas at San Antonio

Kirk Schanze earned his B.S. in Chemistry from Florida State University in 1979 and his Ph.D. in Chemistry from the University of North Carolina at Chapel Hill in 1983. He was appointed a Miller Postdoctoral Fellow at the University of California, Berkeley, from 1984-1986 and began his independent faculty career at the University of Florida in 1986. Schanze was University Distinguished Professor and Prominski Professor of Chemistry at the University of Florida until 2016. He is currently the Robert A Welch Distinguished University Professor at the University of Texas at San Antonio. He was a Senior Editor of the ACS journal Langmuir from 2000-2008. Since 2008, Schanze is Editor-in-Chief of ACS Applied Materials & Interfaces, the ACS journal focused on chemistry and engineering of applications-focused research in materials and interfaces.He has authored or co-authored more than 300 peer-reviewed articles on basic and applied research topics, with a primary focus on organic and organometallic materials chemistry, and is named in 20 patents or disclosures.

 

Prof. Yongsheng Chen, Nankai University

He got his PhD in 1997 at University of Victoria with Prof Reg Mitchel. From 1997-1999, he had worked as a Postdoc at UCLA with Prof Fred Wudl and University of Kentucky with Prof Robert Haddon. From 2003, he has been working at Nankai University as a chair professor.

He has published over 300 papers, including that in Science, Nature, JACS, AM, etc., which have been cited over 50000 times with H-index of 102. He has been recognized as one of highly-cited researchers by Clarivate Analytics since 2014.

 

Prof. Hong Meng, Peking University Shenzhen Graduate School

Hong Meng received his PhD under the guidance of Prof. Fred Wudl from University of California, Los Angeles (UCLA), United States in 2002. He has been working in the field of organic electronics for more than 20 years. His career experiences include working in the Institute of Materials Science and Engineering (IMRE) at Singapore, Lucent Technologies Bell Labs, DuPont Experimental Station. In 2012, Dr. Meng joined a laser printing company and conducted new research in chemical toner synthesis, special rubber composites and conducting ink formulations. He was selected under the Recruitment Program of Global Experts in 2013. In 2014, he moved to the School of Advanced Materials at Peking University Shenzhen Graduate School.

Prof. Meng’s research focuses on organic opto-electronic functional materials and devices: 1. Organic Electrochromics; 2. Sensors; 3. Light-Emitting Diodes; 4. Photovoltaics. He has contributed over 130 peer-reviewed papers (Citations: >6000) in Chemistry and Materials Science fields, filed over 46 US patents, 60 Chinese patents, published several book chapters and co-edited one book titled “Organic Light-Emitting Materials and Devices”.

 

Prof. Qichun Zhang, City University of Hong Kong

Qichun Zhang obtained his B.S. at Nanjing University in China in 1992, MS in physical organic chemistry (organic solid lab) at Institute of Chemistry, Chinese Academy of Sciences in 1998, MS in organic chemistry at University of California, Los Angeles (USA), and completed his Ph.D. in chemistry at University of California Riverside in 2007. Then, he joined Prof. Kanatzidis’ group at Northwestern University as a Postdoctoral Fellow (Oct. 2007 –Dec. 2008). Since Jan. 2009, he joined School of Materials Science and Engineering at Nanyang Technological University (NTU, Singapore) as an Assistant Professor. On Mar 1st, 2014, he has promoted to Associate Professor with tenure. On Sep 1st 2020, he moved to Department of Materials Science and Engineering at City University of Hong Kong as a full professor. Currently, he is an associate editor of J. Solid State Chemistry, the International Advisory Board member of Chemistry – An Asian Journal, the Advisory board member of Journal of Materials Chemistry C, the Advisory board member of Materials Chemistry Frontiers, and the Advisory board member of Inorganic Chemistry Frontiers. Also, he is Guest Editor of Inorganic Chemistry Frontiers (2016-2017), Guest Editor of Journal of Materials Chemistry C (2017-2018), and Guest Editor of Inorganic Chemistry Frontiers (2017-2018). In 2018, 2019 and 2020, he has been recognized as one of highly-cited researchers (top 1%) in cross-field in Clarivate Analytics. He is a fellow of the Royal Society of Chemistry. Currently, his research focuses on carbon-rich conjugated materials and their applications. Till now, he has published >395 papers and 5 patents (total citation > 20000, and H-index: 79).

Chair:

Prof. Dmitrii F. Perepichka, McGill University

He studied at Donetsk State University in Ukraine and received PhD in chemistry from the Institute of Physical Organic Chemistry, National Academy of Sciences of Ukraine in 1999. This was followed by post-doctoral training at Durham University with Martin Bryce and at UCLA with Fred Wudl. After his first appointment at INRS-Energy, Materials and Telecommunications, Canada (2003), he moved to McGill University in 2005. The contributions of his research group include low-gap donor-acceptor systems, two-dimensional polymers and covalent organic frameworks, luminescent organic semiconductors, on-surface self-assembly, supramolecular design of semiconductors.

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)

Purity of organic semiconductors substantially increase the performance of organic transistors

By .

In their recent paper in Materials Chemistry Frontiers, published by the Royal Society of Chemistry, the authors Cigdem Yumusak, Niyazi Serdar Sariciftci, Mihai Irimia-Vladu, from the Linz Institute for Organic Solar Cells (LIOS), Physical Chemistry at the Johannes Kepler University Linz, Austria investigated the effects of purification of different organic semiconductors (i.e. n-type, p-type, and ambipolar) in performance of organic field effect transistors (OFETs). The results clearly indicate that performance for the field of organic field effect transistors can be enhanced orders of magnitude by the purification.

Fig. 1: Schematic view of the OFET architecture

Organic semiconductors are interesting through their versatility in high throughput at low cost of production. For achieving the coveted goal of “green” and sustainable electronics development, one can tailor and make these materials biocompatible and biodegradable. The large-scale electronic waste produced in the world is creating trouble in the supply chain of rare earth materials as well as plastic waste contamination in oceans, due to packaging materials in general. Both these unfortunate events can be faced successfully if we introduce the biodegradable organic semiconductors, substrates and plastics.

Back in 2011 there were already crystalline OFETs with the mobility values exceeding those of amorphous silicon. Nevertheless, reaching values of field effect mobility in excess of 10 cm2/Vs remains a tremendous challenge for organic semiconductors and rather difficult to materialize at the same time. More often than not, organic electronic devices are fabricated with the “as received” materials carrying the declared purity by the chemical supplier. Nevertheless, when the effort of purification was invested, then the results improved impressively, with the recorded mobility of the organic semiconductor reaching record values in excess of 5 cm2/Vs for single crystal based OFETs with rubrene. Importantly also, time of flight measurements at low temperature of ultra-pure oligomeric systems of organic semiconductors showed that mobilities of 10 cm2/Vs at room temperature and of several hundred cm2/Vs at low temperatures are possible to achieve.

In this work, authors tackle the issue of materials’ purity and its influence on organic electronic devices systematically. They compared the effect of different materials as well as different purification degrees respectively, on the performance of fabricated devices. This is to demonstrate systematically the influence of this “purification versus performance” relationship. For this study a large pool of organic semiconductor materials, with n-, p-, and ambipolar-type of charge transport were investigated. The selected semiconductors for this study were: fullerene (C60), pentacene, copper phthalocyanine, indigo (vat blue 1), Tyrian purple, epindolidione, quinacridone and indanthrene blue RS (vat blue 4), the latter 5 molecules belonging to the group of hydrogen bonded (bio)-organic semiconductors.

Fig. 2: Molecular structure of the organic semiconductors used in this study: (from upper left to lower right) Fulleren C60, pentacene, copperphtalocyanine, indanthrene Blue RS, quinacridone, epindolidione, Tyrian purple (dibromoindigo) and indigo.

The method of purification of the organic semiconductors investigated in this study was the train sublimation method shown in Fig.3.

Fig. 3: Photograph of the train sublimation oven showing the sublimed material in the vacuum tube

As an example of the effect of purification take a look at the increase of field effect mobility by several order of magnitude by different purification steps using epindolidione.

Fig. 4: a) Comparison of OFET devices with three different purity grades of epindolidione semiconductor: unpurified (0X in graph legend), one time purified (1X in graph legend) and three times purified respectively (3X in graph legend); b) the Sqrt(Ids) vs. Vgs of the three purity grades presented in panel a)

Indeed, starting from very low field effect mobility of the “as received” material of 4.4×10-6 cm2/Vs, epindolidione based OFETs almost reached the mobility of 0.1 cm2/Vs after being subjected to three steps of purification. This tremendous mobility improvement was accompanied by a decrease of the subthreshold swing from 11.3 V/dec. to 1.9 V/dec. and an increase of the ON/OFF ratio from 3.5 to 3.5×104, literally a 10000-fold improvement.

 

Authors:

Çiğdem Yumuşak is postdoctoral researcher at the Linz Institute for Organic Solar Cells (LIOS) and Physical Chemistry at the Johannes Kepler University of Linz, Austria. She completed her BSc., MSc., and PhD degrees in Physics at the Yildiz Technical University, Istanbul, Turkey. Her scientific interests focus on semiconductor physics, bio-origin materials and their implementation into organic electronic devices, and bioelectronics.

 

Niyazi Serdar Sariciftci is Ordinarius Professor for Physical Chemistry and the Founding Director of the Linz Institute for Organic Solarcells (LIOS) at the Johannes Kepler University of Linz/Austria. He graduated as PhD in physics in Vienna. After postdoctoral study at the University of Stuttgart he joined the Institute for Polymers and Organic Solids at the University of California, Santa Barbara, USA.  Since 1996 he moved to Linz. He is the inventor of conjugated polymer and fullerene based “bulk heterojunction” solar cells. Prof. Sariciftci published over 600 publications and with over 75000 citations he is one of the most cited scientists in material science (2011, Thompson Reuter ranking No: 14 of the world in material science).  He is a corresponding member of the Academy of Science in Austria (ÖAW) and a member of the Turkish Academy of Sciences in.

 

Dr. Mihai Irimia-Vladu obtained his PhD from the Materials Engineering Department of Auburn University, Alabama, USA in August 2006, under the guidance of Prof. Jeffrey Fergus. He moved to Johannes Kepler University in Linz, Austria as a post-doctoral researcher in the groups of the late Prof. Siegfried Bauer (Soft Matter Physics) and Prof. Niyazi Serdar Sariciftci (Physical Chemistry) where he initiated research activity on biocompatible and biodegradable materials for electronics.  After an employment at the Department of Surface Technologies and Photonics of Joanneum Research mbH in Weiz, Austria, Dr. Mihai Irimia-Vladu is back at Johannes Kepler University Linz as Assistant Professor in the Department of Physical Chemistry, where he continues his research investigations of environmentally friendly materials for bioelectronics and energy harvesting devices development.

Article information:

Purity of Organic Semiconductors as a Key Factor for the Performance of Organic Electronic Devices
Cigdem Yumusak, Niyazi Serdar Sariciftci and Mihai Irimia-Vladu
Mater. Chem. Front., 2020, Accepted Manuscript
https://doi.org/10.1039/D0QM00690D

Digg This
Reddit This
Stumble Now!
Share on Facebook
Bookmark this on Delicious
Share on LinkedIn
Bookmark this on Technorati
Post on Twitter
Google Buzz (aka. Google Reader)