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Title: Microlens array induced light absorption enhancement in polymer solar cells

Over the last decade, polymer solar cells (PSCs) have attracted a lot of attention and highest power conversion efficiencies (PCE) are now close to 10%. Here we employ an optical structure – the microlens array (MLA) – to increase light absorption inside the active layer, and PCE of PSCs increased even for optimized devices. Normal incident light rays are refracted at the MLA and travel longer optical paths inside the active layers. Two PSC systems – poly(3-hexylthiophene-2,5-diyl):(6,6)-phenyl C61 butyric acid methyl ester (P3HT:PCBM) and poly[[9-(1-octylnonyl)-9H-carbazole-2,7-diyl]-2,5-thiophenediyl-2,1,3-benzothiadiazole-4,7-diyl-2,5-thiophenediyl]:(6,6)-phenyl C71 butyric acid methyl ester (PCDTBT:PC70BM) – were investigated. In the P3HT:PCBM system, MLA increased the absorption, absolute external quantum efficiency, and the PCE of an optimized device by [similar]4.3%. In the PCDTBT:PC70BM system, MLA increased the absorption, absolute external quantum efficiency, and PCE by more than 10%. In addition, simulations incorporating optical parameters of all structural layers were performed and they support the enhancement of absorption in the active layer with the assistance of MLA. Our results show that utilizing MLA is an effective strategy to further increase light absorption in PSCs, in which optical losses account for [similar]40% of total losses. MLA also does not pose materials processing challenges to the active layersmore » since it is on the other side of the transparent substrate.« less
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [2] ;  [1] ;  [1]
  1. Ames Laboratory
  2. Iowa State University
Publication Date:
OSTI Identifier:
1082681
Report Number(s):
IS-J 7953
DOE Contract Number:
DE-AC02-07CH11358
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Chemistry Chemical Physics; Journal Volume: 2013; Journal Issue: 12
Research Org:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY