开路电压
材料科学
聚合物太阳能电池
富勒烯
载流子
太阳能电池
光电子学
异质结
电压
化学物理
重组
聚合物
物理
化学
复合材料
基因
有机化学
量子力学
生物化学
作者
Sarah R. Cowan,Anshuman Roy,Alan J. Heeger
出处
期刊:Physical Review B
[American Physical Society]
日期:2010-12-16
卷期号:82 (24)
被引量:1723
标识
DOI:10.1103/physrevb.82.245207
摘要
Recombination of photogenerated charge carriers in polymer bulk heterojunction (BHJ) solar cells reduces the short circuit current $({J}_{sc})$ and the fill factor (FF). Identifying the mechanism of recombination is, therefore, fundamentally important for increasing the power conversion efficiency. Light intensity and temperature-dependent current-voltage measurements on polymer BHJ cells made from a variety of different semiconducting polymers and fullerenes show that the recombination kinetics are voltage dependent and evolve from first-order recombination at short circuit to bimolecular recombination at open circuit as a result of increasing the voltage-dependent charge carrier density in the cell. The ``missing 0.3 V'' inferred from comparison of the band gaps of the bulk heterojunction materials and the measured open-circuit voltage at room-temperature results from the temperature dependence of the quasi-Fermi levels in the polymer and fullerene domains---a conclusion based on the fundamental statistics of fermions.
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