The 39th Photovoltaic Specialists Conference in Tampa, Florida was a great conference. Photovoltaic specialists from all over the world gathered at the paradise of recreation, learning the most recent developments in this field delivered by hundreds of high quality presentations and posters. The topics span across eleven general areas from fundamental and new concepts of PV to the supporting of PV innovation with little to none overlap between each area. For me, an organic chemist focusing on developing new polymers to improve the stability of organic photovoltaics (OPV), the area that mostly interested me was, without a doubt, OPV.

Thursday of last week was the day for OPVs. In the morning, Professor Christian Körner from Heliatek GmbH gave a talk on the recent progress of organic solar cells [1].  Like a typical general review of this field, the talk started with some fundamental concepts and theories of organic semiconductors, then moved to some developments that aimed at solving the issues commonly encountered when applying organic materials to photovoltaic devices. He also covered recent improvements on the lifetime and module efficiencies of OPVs, which are not as much discussed as the efficiencies of lab scale devices. Not surprisingly, the materials presented in this talk are highly related to those being developed at Heliatek. With active materials based on small molecules and p-i-n structured devices, they could achieve 12% of photo conversion efficiency on lab scale devices and 9% on 100 cm2 scale modules that last as long as several thousand hours under intensified illumination. However, from an academic point of view, these technologies and accomplishment do not necessarily reflect the general recent progress of OPV in academia, where polymers and bulk heterojunctions are the dominant materials and device structure, respectively. Regarding the progress of OPV using conventional structures and material, there was an interesting presentation in the afternoon session given by an award winning Ph.D. candidate Biswajit Ray from Purdue University [2]. In his research work, he showed that the limiting factor of the charge transportation process are recombinations happening at the neutral, flat region of the band diagram. Conventionally, many people think the limiting factor is charge mobility. Although his evidence is not sufficient enough, it is helpful to look at a problem from a view that opposes the convention.

Apart from the presentation content, a new presentation technique was unveiled at one of the plenary talks. In it, the presenter used a facebook homepage to deliver his talk with the aid of the timeline function. At the end, an internet address that directs to that facebook page made all the slides publically accessible. It is notable that people’s attention was drawn to this presentation even though some of them were not familiar with the field.

It was a wise idea that the conference committee chose to hold it in Tampa Bay. It was the best time of the year to go there and to the beach where the water was warm and the sand was fine and soft like snow. Everyone from the network that went to the beach had a wonderful time there. Also, the Salvador Dalí Museum is definitely worth seeing, since it holds the largest number of Dalí’s masterpieces which will truly stun you.

[1] C. Körner, M. Hermenau, C. Elschner, C. Schunemann, S. Mogck, M. Riede, K. Leo, “Recent progress in organic solar cells: From a lab curiosity to a serious photovoltaic technology” in 2013 39th IEEE Photovoltaic Specialists Conference (PVSC), 2013.

[2] B. Ray and M. Alam “Role of charged defects on organic solar cell performance: Prospect of Heterojunction-free device design” in 2013 39th IEEE Photovoltaic Specialists Conference (PVSC), 2013.

Ben Zhang's picture

Chi Zhang (Ben)

Ph.D. Candidate, Year 3

Simon Fraser University, Burnaby, British Columbia