Charge transport layers in organic photovoltaics (OPV) : challenges and opportunities for the large-scale deployment of OPV

Organic photovoltaics present a great opportunity to decarbonize the worlds energy generation. Due to their versatility in terms of colors, mechanical flexibility, light weight, containing abundant elements and the inherent flexibility of organic chemistry, on which they are based, they could allow for fast deployment of photovoltaics in hitherto not seen scenarios and at massive scales in potentially very short times. They have by now reached efficiencies of 14% on the scale of small modules though they are unfortunately still lacking behind other PV technologies, though a-Si modules, which still have niche applications like semi-transparent glassing actually has lower efficiencies. Beyond efficiency long lifetimes have been presented even for the latest high performing materials extrapolated under illumination of up to 30 years. By now there is also a broad understanding of the fundamental processes in organic solar cells. This applies to how charges are generated, as well as how they degrade. Though the broad strokes are well understood, there are many fine details still to be etched out, which will be important to further develop OPV in a more focused manner. As at present much of their development is still primarily driven by serendipitous exploration of new materials and processing methods. Especially in terms of the active layer materials. But beyond active layer materials also charge transport layers have gained a lot of focus in the resent years, as they can greatly impact stability and performance as well. In this work the agrivoltaics is presented as an interesting niche for upscaling of OPV and it is discussed in how far charge transport layers in such OPV devices are playing an important role in terms of their transparency, their impact on performance and stability. Finally a newly developed method is introduced for they analysis of JV-curves of solar cells for the fast detection of defects.