RECENT PROGRESS IN POLYMER SOLAR CELLS AND TANDEM POLYMER SOLAR CELLS

摘要

Polymer solar cells (PSC) is promising technology for potential low-cost solar electricity energy generation and has drawn great attention.1 So far, single junction PSCs based on conjugated polymers as electron-donor materials blended with [6,6]-phenyl-C_(71)-butyric acid methyl ester (PC71BM) as an electron-acceptor material have achieved around 8% power conversion efficiency (PCE) using a bulk heterojunction (BHJ) device structure. However, further increasing PCE is challenging for single junction devices, because photons with energy smaller than the bandgap cannot be absorbed (loss of photocurrent) and photons with larger energy will lose their excess energy via a thermalization process of the hot carriers (loss of photovoltage). Alternatively, tandem solar cells can reduce these losses by using separate sub-cells each convert a different part of the solar spectrum, and can realize quantum jump in solar cell efficiency.