The power conversion efficiency (PCE) of solar cells and their open circuit voltage (Voc) are directly related. In the majority of organic photovoltaics (OPV) the Voc is significantly lower than the energy of photon absorption, as determined by the donor material bandgap (Eg) in the case of most conjugated polymer:fullerene bulk heterojunctions (BHJ). Minimizing energy losses, from Eg to Voc, could significantly increase the PCE in organic solar cells. In this talk, I will discuss different type of energy loss in polymer BHJ solar cells and report a BHJ system having very low Voc loss and still maintaining a PCE &gt; 6%. Using a combination of characterization methods, we find that in a blend, the polymer has low energetic disorder. Structural characterization of the blend films show crystalline features not observed in polymer:fullerene blends, illustrating a high degree of structural order. These observations provide insight into a BHJ system that is able to efficiently generate charge carriers despite marginal energetic offsets.<br/>

Understanding voltage loss in organic bulk heterojunction solar cells

251st National Meeting (2016)

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