EES Blog

Energy & Environmental Science and Sustainable Energy & Fuels are delighted to be supporting the International Conference on Novel Materials for Energy Conversion and Optoelectronics taking place in Santa Fe, United States, between 11-12 December 2018.

The scope of the conference covers a broad range of research directions related to novel materials for applications in energy conversion and optoelectronics ranging from photovoltaics and photoelectrochemical and photocatalytic production of solar fuels, to sensing and light emission in electroluminescent devices and lasers. Particular emphasis is on understanding the relationship between the structural properties of materials and their function in final devices, which is key to fostering further advances in device performance. Consequently, novel theoretical and characterization tools represent topics of keen interest to this conference.

Scientists in South Korea have created a material that emits bright white light when a stream of nitrogen is blown over it. The discovery paves the way for eco-friendly displays and lighting systems powered by natural winds.

Mechanoluminescence, where materials emit light under mechanical stress, is not a new phenomenon; in 1605 Francis Bacon reported seeing flashes of light when he snapped sugar crystals. But, as this required the crystals to be fractured, mechanoluminescence was not thought to have any practical applications until elasto-mechanoluminescent materials were discovered in 1999. These materials emit light under elastic deformation without being destroyed, and can be used for lighting, medical imaging or even as artificial skin.

However, all of the elasto-mechanoluminescent materials discovered so far have several associated problems. One problem is the light they produce is very faint, and is usually only as bright as luminescent paint. Another problem is that the light is coloured, often green or yellow, depending on the compounds used. This is a stumbling block for applications where white light is preferable.

Both of these problems have been addressed by Soon Moon Jeong’s team from the Daegu Gyeongbuk Institute of Science and Technology. By incorporating a mixture of coloured phosphors made from copper-doped zinc sulfide into a flexible plastic polydimethylsiloxane composite, the researchers created an elasto-mechanoluminescent material that emits white light. The colour of the light can also be tuned by changing the proportion each phosphor.

Interested to find out more? Read the full article by Stephen McCarthy in Chemistry World.

Read the original article in Energy & Environmental Science:

Bright, wind-driven white mechanoluminescence from zinc sulphide microparticles embedded in a polydimethylsiloxane elastomer
Soon Moon Jeong, Seongkyu Song, Kyung-Il Joo, Joonwoo Kim, Sung-Ho Hwang, Jaewook Jeong and Hyunmin Kim
Energy Environ. Sci., 2014, Advance Article
DOI: 10.1039/C4EE01776E

Energy and Environmental Science author Aaron Wheeler (University of Toronto) was recently interviewed in Chemistry World about his recent paper describing a technique that can screen algae with the aim of generating more efficient biofuels.

Here’s the beginning of the interview:

You recently reported an exciting technique that can screen algae grown under different wavelengths with the aim of generating more efficient biofuels.¹ Can you tell me more about this work?

Sure, this was the first time we have developed a method for the area of renewable energy. I had a student, Steve Shih, who is now a postdoc at the Joint BioEnergy Institute in California, who became interested in the idea that we can cultivate algae to produce biofuel. Of course this is an idea that has been around for a while.

So, in looking at the problem it seems that the biofuel we can collect from algae does not have the required energy density relative to the cost needed to extract and generate fuel, to compete with non-renewable resources. There are ongoing efforts to develop ways to encourage algae to generate more lipids. The idea is that the algae generate stores of lipids that we can then extract and refine into fuel.

We saw an opportunity; we thought we might be able to build a microfluidic device that could rapidly screen for conditions that folks haven’t looked at before just to see if we could find some conditions that encouraged the algae to produce more lipids. A lot of time we start these projects but don’t end up with an exciting result, but this one was really exciting in that we believe we have identified a brand new phenomenon which is that, at least for this particular algae, if you culture them under yellow light they experience some sort of stress which causes them to increase lipid production!

Visit Chemistry World now to read the rest!

1. S C C Shih et al, Energy Environ. Sci., 2014, 7, 2366 (DOI: 10.1039/c4ee01123f)

A lead-free and non-toxic alternative to current perovskite solar-cell technology has been reported by researchers in the UK: tin halide perovskite solar cells. They are also cheaper to manufacture than the silicon solar cells currently dominating the market.

Nakita Noel, part of Henry Snaith’s research team at the University of Oxford, describes how perovskite materials have caused a bit of a whirlwind since they came out in 2009: ‘Everybody that’s working in the solar community is looking to beat silicon.’ Despite the high efficiency of conventional crystalline silicon solar cells (around 20%), high production and installation costs decrease their economic feasibility and widespread use.

The challenge to find a cheaper alternative led to the development of perovskite-based solar cells, as organic–inorganic metal trihalide perovskites have both abundant and cheap starting materials. However, the presence of lead in some semiconductors could create toxicology issues in the future. As Noel puts it ‘every conference you present at somebody is bound to put up their hand and ask “What about the lead – isn’t this toxic?”

Interested to find out more? Read the full article by Vicki Marshall in Chemistry World.

Read the original article in Energy & Environmental Science.

Lead-Free Organic-Inorganic Tin Halide Perovskites for Photovoltaic Applications
Nakita K. Noel, Samuel D. Stranks, Antonio Abate, Christian Wehrenfennig, Simone Guarnera, Amir Haghighirad, Aditya Sadhanala, Giles E Eperon, Sandeep K. Pathak, Michael B Johnston, annamaria petrozza, Laura Herz and Henry Snaith
Energy Environ. Sci., 2014, Accepted Manuscript
DOI: 10.1039/C4EE01076K

Scientists in the UK developing wearable electronics have knitted a flexible fabric that delivers twice the power output of current energy harvesting textiles.

There is considerable interest and research into wearable piezoelectric energy harvesters that use waste energy from human movement or the ambient environment to power low-energy consuming wearable devices, such as wireless sensors and consumer electronics. Typically these materials are ceramic-based with limited flexibility, so aren’t that comfortable to wear, and include toxic elements like lead. They also involve charge-collecting metallic electrodes with poor fatigue resistance that fail after repeated use. New, less rigid materials with sufficient mechanical strength and an all-in-one design are therefore highly sought after.

The polymeric piezoelectric fibres created by Navneet Soin at the University of Bolton and colleagues in the laboratory of Elias Siores fulfill all of the above: they are flexible, strong and breathable.

Interested to know more? Read the full news article by Polly Wilson on Chemistry World here…

Read the article by N Soin et al. in EES:

Novel “3-D spacer” all fibre piezoelectric textiles for energy harvesting applications
Navneet Soin, Tahir Shah, Subhash Anand, Junfeng Geng, Wiwat Pornwannachai, Pranab Mandal, David Reid, Surbhi Sharma, Ravi Hadimani, Derman Vatansever Bayramol and Elias Siores
Energy Environ. Sci., 2014, Accepted Manuscript
DOI: 10.1039/C3EE43987A, Paper

The latest issue of EES is now online. You can read the full issue here.

The outside front cover features the paper Exciton diffusion in organic photovoltaic cells by S. Matthew Menke and Russell J. Holmes.

Lead candidates for high-performance organic photovoltaics from high-throughput quantum chemistry – the Harvard Clean Energy Project is the paper highlighted on the inside front cover by Johannes Hachmann, Roberto Olivares-Amaya, Adrian Jinich, Anthony L. Appleton, Martin A. Blood-Forsythe, László R. Seress, Carolina Román-Salgado, Kai Trepte, Sule Atahan-Evrenk, Süleyman Er, Supriya Shrestha, Rajib Mondal, Anatoliy Sokolov, Zhenan Bao and Alán Aspuru-Guzik.

Issue 2 contains a number of excellent Analysis, Review and Perspective articles:

Energy demand and emissions of the non-energy sector
Vassilis Daioglou, Andre P. C. Faaij, Deger Saygin, Martin K. Patel, Birka Wicke and Detlef P. van Vuuren

Lithium metal anodes for rechargeable batteries
Wu Xu, Jiulin Wang, Fei Ding, Xilin Chen, Eduard Nasybulin, Yaohui Zhang and Ji-Guang Zhang

Recent progress on flexible lithium rechargeable batteries
Hyeokjo Gwon, Jihyun Hong, Haegyeom Kim, Dong-Hwa Seo, Seokwoo Jeon and Kisuk Kang

Enhancing SOFC cathode performance by surface modification through infiltration
Dong Ding, Xiaxi Li, Samson Yuxiu Lai, Kirk Gerdes and Meilin Liu

Heterogeneous nanocarbon materials for oxygen reduction reaction
Da-Wei Wang and Dangsheng Su

Directing the film structure of organic semiconductors via post-deposition processing for transistor and solar cell applications
Anna M. Hiszpanski and Yueh-Lin Loo

Silver is a scarce raw material but the first real scale study of recycling polymer solar cells reveals that its use can be sustainable.

Putting up huge nubers of solar panels every day could help address the world’s energy crisis. ‘If you want to solve big problems, then the scale of whatever you are doing is also likely to be big, and so is any waste you generate,’ explains Frederik Krebs who led the study at the Technical University of Denmark. ‘This should therefore be part of your thinking when you are developing something.’

Silver is needed for solar cell electrodes but it is also a precious metal, cutting into both the cost of production and energy payback time of mass-produced solar cells. Now, Krebs’ team has demonstrated that 95% of the silver electrodes in polymer solar cell modules can be reclaimed as silver chloride after simply shredding the modules and soaking them in nitric acid. This yield would diminish the overall energy payback time of the solar cells from 139 days to 128 days, a decrease of 8%.

Interested to know more? Read the full news article by Jennifer Newton on Chemistry World here…

Read the article by R R Søndergaard et al. in EES:

Efficient decommissioning and recycling of polymer solar cells: justification for use of silver
Roar R. Søndergaard, Nieves Espinosa, Mikkel Jørgensen and Frederik C. Krebs
Energy Environ. Sci., 2014, Advance Article
DOI: 10.1039/C3EE43746A, Communication