CrystEngComm Blog

Following on from a previous blog on CuInS₂ nanocrystals, this post is about a very similar material: AgInS₂ nanocrystals! Similar to CuInS₂, AgInS₂ also shows desirable properties such as a suitable band gap energy, high absorption coefficient and low toxicity, making them good candidates for optoelectronic devices. As the size and morphology of these crystals determine how they perform, it will be useful to produce nanocrystals with uniform shapes and sizes.

In this paper, a method of synthesising AgInS₂ nanocrystals with a uniform size is presented. The authors also demonstrated a way to vary the size of the crystals by changing the composition of the solvents in which the crystals form. An investigation of the photoelectric properties of the AgInS₂ nanocrystals was carried out, in which the crystal were hybridised with poly (3-hexylthiophene) to form nanodevices. These devices operate as switches, and with their high sensitivity to light, fast response times, and stability to reversal, can be utilised in many photoelectric applications.

Read their article and find out more:

Controlled synthesis of AgInS₂ nanocrystals and their application in organic–inorganic hybrid photodetectors
Manjiao Deng, Shuling Shen, Xuewen Wang, Yejun Zhang, Huarui Xu, Ting Zhang and Qiangbin Wang
CrystEngComm, 2013, Advance Article
DOI: 10.1039/C3CE40173A, Communication

CuInS₂ belongs to a class of inorganic semiconductors known as metal chalcogenides, which have desirable optical properties that make them useful in photovoltaics. In solar cell applications, CuInS₂ is usually deposited as nanocrystals, and the size, shape and structure of these crystals determine the properties of the device. Therefore, it will be desirable to have a synthetic method that can produce crystals with a uniform morphology, and to be able to vary this by changing the synthetic conditions.

Jin Chang and Eric R. Waclawik have achieved this by a wet-chemical method in which CuInS₂ forms nanocrystals with a zincblende structure when a weak-coordinating solvent is used, whereas strong-coordinating solvents produce a wurzite structure. The authors were also able to explain the effect by investigating the intermediate species formed during the chemical reaction. This synthetic method was also extended to two other useful materials: Cu₂SnS₃ and Cu₂ZnSnS₄, and they were able to produce pure zincblende or wurzite structures depending on the solvent used.

The synthetic process presented in this paper has the potential to be used in fine tuning the optoelectronic properties of photovoltaic materials, thus yielding better devices for solar energy generation.

Read their article to find out more. 

Controlled synthesis of CuInS₂, Cu₂SnS₃ and Cu₂ZnSnS₄ nano-structures: insight into the universal phase-selectivity mechanism
Jin Chang and Eric R. Waclawik
CrystEngComm, 2013, Advance Article
DOI: 10.1039/C3CE40284C

Metal organic frameworks (MOFs) are porous materials with a high surface area. This makes them useful  for processes such as catalysis and gas storage, including hydrogen storage, which is crucial for environmentally friendly energy applications.

Nevertheless, many MOF structures can only hold onto H₂ molecules at very low temperatures and concentrations. To enable the MOF to hold onto H₂ molecules at higher temperatures and concentrations, Lalonde and colleagues have synthesized MOFs with a zwitterionic structure, where the negatively charged Zn₂(CO₂)₅ groups are separated from the positive imidazole tetra acid groups. The material shows enhanced H₂ adsorption, and is a good candidate for further optimisation. The zwitterionic design can also be applied to synthesizing other MOF structures or porous materials  for use in H₂ storage.

Read their article to find out more:

A zwitterionic metal–organic framework with free carboxylic acid sites that exhibits enhanced hydrogen adsorption energies
Marianne B. Lalonde, Rachel B. Getman, Jeong Yong Lee, John M. Roberts, Amy A. Sarjeant, Karl A. Scheidt, Peter A. Georgiev, Jan P. Embs, Juergen Eckert, Omar K. Farha, Randall Q. Snurr and Joseph T. Hupp
CrystEngComm, 2013, Advance Article
DOI: 10.1039/C3CE40198G

Lotus leaves are superhydrophobic due to their microstructure, and Shuxi Dai and colleagues have pioneered a method of replicating this in a ZnO film by a ‘bottom up’ method. Using real lotus leaves as templates, they replicated the microstructure on ZnO films. The material consists of an array of micropillars, on which further nanostructures form after a second hydrothermal treatment. Depending on the solution used in the second stage, properties of the final structure, such as hydrophobicity, can be tuned.

Many natural materials have microstructures that give them desirable chemical or mechanical properties, and the method presented in this paper enables scientists to mimic them easily on other materials such as functional metal oxides.

Find out more from their article.

Biomimetic fabrication and tunable wetting properties of three-dimensional hierarchical ZnO structures by combining soft lithography templated with lotus leaf and hydrothermal treatments
Shuxi Dai, Dianbo Zhang, Qing Shi, Xiao Han, Shujie Wang and Zuliang Du
CrystEngComm, 2013, Advance Article
DOI: 10.1039/C3CE40238J

Self-assembled Fe₃O₄ superstructures have unique electric and magnetic properties, such as allowing the material to exceed the ‘‘superparamagnetic limit’’ found in Fe₃O₄ with a less well defined structure. Using a novel way of synthesising Fe₃O₄ nanoflakes via an ionic liquid-assisted solvothermal process, Xiaodi Liu and colleagues have made self-assembled Fe₃O₄  structures from nanoparticles. These nanoflakes have a good monodispersity and magnetic properties that are not seen in material made by other synthetic methods, making them good candidates for applications such as high density magnetic recording.

In this study, the authors have also explored how different growth conditions affect the final structure, thus providing a method for optimising the process for making other self-assembled nanomaterials using ionic liquids.

Find out more by downloading their paper:

Ionic liquid-assisted solvothermal synthesis of oriented self-assembled Fe₃O₄ nanoparticles into monodisperse nanoflakes
Xiaodi Liu, Xiaochuan Duan, Qing Qin, Qinglun Wang and Wenjun Zheng

CrystEngComm, 2013, Advance Article
DOI: 10.1039/C3CE00035D, Communication

By looking at the structures of halogen-bonded infinite chains with two diiodoperfluoroalkanes and a bent bis(pyrid-4′-yl)oxadiazole, Giuseppe Resnati and colleagues have investigated the influence that halogen bond directionality has on supramolecular design.  The bent geometry of the pyridyl pendant rings in the structures were found to translate into the angle between the formed halogen bonds, taking precedence over parameters that might affect the crystal packing.

Download their HOT CrystEngComm communication today to find out more…

Halogen bond directionality translates tecton geometry into self-assembled architecture geometry
Marco Saccone, Gabriella Cavallo, Pierangelo Metrangolo, Andrea Pace, Ivana Pibiri, Tullio Pilati, Giuseppe Resnati and Giancarlo Terraneo
CrystEngComm, 2013
DOI: 10.1039/C3CE40268A, Communication

This communication is part of a themed issue on Halogen bonding (guest edited by Giuseppe Resnati, Mark Taylor and William Pennington) which is due to go online next week.

Producing nanotubes of biocompatible hydroxyapatite by continuous hydrothermal synthesis
Edward Lester, Selina V. Y. Tang, Andrei Khlobystov, Vanessa Loczenski Rose, Lee Buttery and Clive J. Roberts

CrystEngComm, 2013, Advance Article, DOI: 10.1039/C3CE26798A

Free to access until 21st April

Knowledge-based hydrogen bond prediction and the synthesis of salts and cocrystals of the anti-malarial drug pyrimethamine with various drug and GRAS molecules
Amit Delori, Peter T. A. Galek, Elna Pidcock, Mohit Patni and William Jones

CrystEngComm, 2013,15, 2916-2928, DOI: 10.1039/C3CE26765B

Free to access until 21st April

Thermodynamics and nucleation of the enantiotropic compound p-aminobenzoic acid
Michael Svärd, Fredrik L. Nordström, Eva-Maria Hoffmann, Baroz Aziz and Åke C. Rasmuson

CrystEngComm, 2013, Advance Article, DOI: 10.1039/C3CE26984A

Free to access until 21st April

 Andrew Farrell and colleagues have conducted the first ever ultra-low temperature (2K) study of the crystal structure of the single molecule magnet, [Mn₁₂OAc], [Mn₁₂O₁₂(O₂CMe)₁₆(H₂O)₄]•4H₂O•2MeCO₂H. This is the temperature where the molecule exhibits its most interesting properties.

Using a combination of single crystal X-ray diffraction and neutron diffraction, they were able to provide a better model of the molecular structure and to explain the special quantum properties of the single molecule magnet. A study of the species with the solvents removed also yielded further clues to the nature of the disorder in the solvated species.

Find out more by downloading the full paper now:

Ultra-low temperature structure determination of a Mn₁₂ single-molecule magnet and the interplay between lattice solvent and structural disorder
Andrew R. Farrell, Jonathan A. Coome, Michael R. Probert, Andres E. Goeta, Judith A. K. Howard, Marie-Helene Lemee-Cailleau, Simon Parsons and Mark Murrie
CrystEngComm, 2013, Advance Article
DOI: 10.1039/C3CE00042G