Research

May 1, 2014

Status of Organic Photovoltaics

The 28th European photovoltaic solar energy conference and exhibition (EU PVSEC) was held in Paris from September 30 to October 4, 2013.  This European event attracted conference delegates and exhibition attendees from around the globe.  The scientific conference featured acclaimed international researchers who discussed their ground breaking research in numerous sectors related to solar energy.  This multi-disciplinary aspect is one of the greatest attributes of the EU PVSEC.  This international congress helps unify the many fields associated with photovoltaic solar energy research and development. An emerging PV sector, encompassing a diverse array of young solar technologies, includes dye-sensitized, organic, inorganic, quantum dot and perovskite cells. This sector of third generation cells has seen a large improvement in power conversion efficiencies over the past 5 years.  This year’s world record perovskite cell reached an efficiency of 14.1%, which surpasses the dye-sensitized record of 11.9%.  The efficiency of organic cells (OPV) has doubled in less than half a decade from 5% to over 10%. 

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April 23, 2014

Organic photovoltaics at EUPVSEC 2013

The 28th European Photovoltaic Solar Energy Conference and Exhibition had many different topics regarding solar energy. From the latest design of cell structure to the marketing of new concepts, every attendee should have seen some recent developments in the field of photovoltaic solar energy. For me, a synthetic chemist, I was most interested in talks regarding organic photovoltaics. Luckily, the keynote speech about organic photovoltaics this year was given by  Prof. Jan Cornelis Hummelen, a world renowned researcher in this field. First, Prof. Hummelen reported some recent progress made in different subdivisions of organic solar cells. Heliateck achieved 12.0 % photo conversion efficiency (PCE) on tandem structures using small molecule organic semiconductors. Compared to the 10.7% they reported last year, this is a fairly impressive achievement. It was also noted in the speech that the all-polymer cell had reached 6.4% efficiency while the triple junction tandem cell had made its way to 9.6%. The tandem cell using standard polymer-fullerene bulk

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March 31, 2014

Fun times in Paris at EUPVSEC 2013!

This year I had the honour of attending the 28th European Photovoltaic Conference and Exhibition (EUPVSEC) in none other than Paris, France! This year’s conference had 1752 research and industrial contributions from 76 countries all over the world. These numbers give you an idea of just how international this conference is! Owing to the fact that EUPVSEC is one of the largest conferences on photovoltaics in the world, this conference had something for everyone who works in the field. The topics ranged from basic research such as promising new materials, to talks on policy and how solar energy fits in amongst other sources energy. This conference is truly an industrial conference however, with most talks focusing on the development and characterization of existing solar technologies, and the improvement of the processes used to make solar cells. Silicon, the most predominant material used in solar cells, was thus featured very heavily in the conference presentations. This was good for me since

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December 12, 2013

Photon Up- and Down-Conversion at IEEE PVSC

Another day, another interesting idea. The ideas were not from my own brain, of course, but from the minds of others. A recent trip to the IEEE Photovoltaic Specialists Conference (PVSC) in Tampa led to both ingredients mentioned by Einstein in his recipe for genius: inspiration (from conference speakers) and perspiration (from Tampa weather). Although all of us PVINers had some talks to attend on technology related to our specific research, it was often in the talks on “Fundamentals and New Concepts for Future Technologies”, or “Area 1”, that one found new ideas that could potentially be applied to a wide-variety of technology bases. This was so much the case, that “when in doubt, go to Area 1” became a mantra. Such wandering brought me to the talks on “up-conversion” and “down-conversion”. Up-Conversion and Down-Conversion of Photons The conversion of photons of one frequency to those of a different frequency is referred to as either up- or down-conversion. This new

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November 28, 2013

PVSC 2013-Fun Times in Florida!

I recently had the opportunity (and pleasure!) of attending the 39th Photovoltaics Specialists Conference (PVSC) in Tampa, Florida. The conference, which is put on by the Institute of Electrical and Electronics Engineers (IEEE), is an annual meeting of scientists and engineers who work in the field of solar energy. PVSC attracts people from all over the world to come and share their research on some of the cutting-edge topics in the field. In this entry I will be providing some highlights of the trip, especially topics that were of interest to me. I once again had the honour of hosting (alongside other HQP) the Photovoltaic Innovation Network (PVIN) booth. As I have mentioned in previous blog entries, the booth is where we get to represent Canada’s research in photovoltaics. A lot of companies and Universities outside of Canada do not know exactly what we do up in Canada in regards to photovoltaic research, so the booth gives us an opportunity

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November 18, 2013

PVSC 2013-Tandem CIGS Solar Cells

A subject that caught my attention during the 39th edition of the Photovoltaic Specialist Conference (PVSC) was a poster from Toshiba Corporation [1] about the study of a homojunction CIGS (Copper Indium Gallium Selenium) solar cell. CIGS solar cells are gaining more and more interest in the photovoltaic community as a thin film solar cell due to the material’s high absorptivity, low cost and relatively high power conversion efficiency.  Standard CIGS solar cell consists of a p-type CIGS base, n-type CdS emitter and a ZnO transparent conductive oxide. This heterojunction between CIGS and CdS results in a conduction band offset. The heterojunction structure is used due to the fact that it is hard to get high enough levels of n-type doping in CIGS. P-type doping in CIGS is usually done intrinsically through Cu vacancies, which act as acceptors. To achieve n-type doping, a donor material would need to be introduced into CIGS.  In their poster, the Toshiba corporation group reported

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October 31, 2013

Spectrum Splitting and Thin Film Photovoltaics at PVSC 2013

At the 39th Photovoltaic Specialist Conference in Tampa, Florida, there were two important and interesting topics which were of particular interest to me. The first one was covered by Harry A. Atwater, California Institute of Technology (http://daedalus.caltech.edu/research/thinfilmpv.php) “Full Spectrum High Efficiency Photovoltaics” [1]. He was discussing a new concept: splitting the incident solar spectrum into its constituent wavelengths, guiding these different wavelengths into solar cells with different bandgaps, then absorbing them (shown in Figure 1).

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October 22, 2013

Highlights from PVSC 2013

The IEEE Photovoltaic Specialist Conference (PVSC) is renowned as one of the world’s largest photovoltaics (PV) conferences. It is also probably the oldest conference that is still been held annually. I was fortunate enough to have the opportunity to attend the conference this year, for the second time. As the PV energy market is evolving from niche to mainstream, I’ve noticed some shift of focus in the topics of this year’s conference. The most noticeable would be the emphasis on the long-term reliability of PV systems. The very first plenary session on Monday morning was dedicated to PV reliability issues, with two talks covering both modeling and analysis of data collected from real field operations. While crystalline silicon is still the dominant technology, exploration into new materials and concepts has never been slowed down. It is the same with this year’s conference. It is my area of interest to discover potential new technologies that can bring fundamental improvement to the

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October 15, 2013

PVSC 2013-Discussions on Photovoltaic System Implementation at the 2013 Photovoltaic Specialist Conference

The 39th IEEE photovoltaic specialist conference was held between June 16th and 21st at the Tampa bay convention center in Tampa, Florida. It was a congregation of industry experts, and research giants. Researchers from NREL, Sandia National Laboratories and Universities across the globe graced the occasion to present their latest studies on photovoltaic system design, implementation and reliability of on-sun PV modules.. The program was significantly all encompassing. Besides the presentations, social activities and mixer programs were held to allow attendees to interact, network and share knowledge. Of notable interest was the presentation of the cherry award to Keith Emery. Previously unknown to me, I found that he is renowned for his contribution to photovoltaic research for his design, development and implementation of IV characterization methods. He pioneered the first generation of hardware, software and procedures to measure current-vs.-voltage characteristics as a function of temperature, spectrum and intensity for single and multi-junction cells and modules. Oral and poster presentations at the

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October 7, 2013

PVSC 2013-Luminescent Coupling

In June, I had the opportunity to attend the IEEE Photovoltaic Specialists’ Conference in Tampa, FL.  This is a huge academic conference covering the entire field of photovoltaics, and has been at the center of photovoltaic research since 1961. One topic that got a lot of discussion this year was ‘luminescent coupling’, a process where energy that is lost through photons radiated from one part of a solar cell can be recovered by absorption in another part of the same cell [1,2].  This has potential to change the way that solar cells – especially very high-efficiency multi-junction solar cells – are designed, either through careful control  of the internal optics of the cell, or by manipulating materials so that photons are emitted in particular directions where they have a high probability of being recovered.  In this way radiative loss, which is an important loss mechanism in multi-junction cells, can be partially suppressed. There is an added benefit to designing cells

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