Dependence of recombination mechanisms and strength on processing conditions in polymer solar cells

作者：Nalwa Kanwar S^*; Kodali Hari K; Ganapathysubramanian Baskar; Chaudhary Sumit

来源：Applied Physics Letters, 2011, 99(26): 263301.

DOI：10.1063/1.3671999

• biochemistry
• molecular biophysics
• photoconductivity
• polymers
• solar cells

Charge carrier recombination due to carrier trapping is not often considered in polymer based solar cells, except in those using non-fullerene acceptors or new donor polymers with limited short-range order. However, we show that even for the canonical poly(3-hexylthiophene): phenyl-C61-butyric acid methyl ester (P3HT:PCBM) system, relative strengths of bimolecular and trap-assisted recombination are strongly dependent on processing conditions. For slow-grown active-layers, bimolecular recombination is indeed the major loss mechanism under one sun illumination. However, for fast-grown active-layers, trap-assisted recombination dominates over bimolecular recombination by an order of magnitude, and recombination strength at short-circuit condition is 3-4 times higher, leading to loss of photocurrent and lowering of fill factor.

• 出版日期2011-12-26