Ultimate efficiency of polymer/fullerene bulk heterojunction solar cells

TLDR

The study models polymer/fullerene bulk heterojunction solar cells to assess their efficiency potential. They model P3HT/PCBM devices, using a 3.5 % efficiency baseline, to evaluate performance improvements. Modeling predicts that reducing the polymer band gap can raise efficiency above 6 %, tuning PCBM levels can push it beyond 8 %, and optimizing band gap, level tuning, and mobilities could achieve efficiencies near 11 %.

Abstract

We present model calculations to explore the potential of polymer/fullerene bulk heterojunction solar cells. As a starting point, devices based on poly(3-hexylthiophene) and 6,6-phenyl C61-butyric acid methyl ester (PCBM), reaching 3.5% efficiency, are modeled. Lowering the polymeric band gap will lead to a device efficiency exceeding 6%. Tuning the electronic levels of PCBM in such a way that less energy is lost in the electron transfer process enhances the efficiency to values in excess of 8%. Ultimately, with an optimized level tuning, band gap, and balanced mobilities polymeric solar cells can reach power conversion efficiencies approaching 11%.