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Title: Roles of Interfacial Tension in Regulating Internal Organization of Low Bandgap Polymer Bulk Heterojunction Solar Cells by Polymer Additives

The role of a tertiary polymer-based additive is investigated in increasing the efficiency of inverted low bandgap polymer:fullerene bulk heterojunction (BHJ) solar cells. Charge separation in polymer BHJ solar cells relies on the phase separation between electron accepting fullerene derivatives and photoactive polymers. Proper distribution of individual phases of suitable crystallinities within the active layer is a key factor for efficient charge transport/extraction and high photovoltaic performance. Here in this paper, it is demonstrated that the minor addition of a tertiary amorphous polymer, polystyrene (PS), with optimized molecular weights can increase the overall photovoltaic efficiency of poly[N-9-heptadecanyl-2,7-carbazole-alt-5,5-(4,7-di-2-thienyl-2,1,3-benzothiadiazole)]:phenyl-C 61butyric acid methyl ester (PCDTBT:PCBM) inverted BHJ solar cells, through the interfacial-tension-driven increase in crystallinities of photoactive phases and redistribution of PCBM molecules away from the top hole-collecting anode interface. Complementary studies correlating polymer interfacial tension, blend internal structure, charge transport, and photovoltaic characteristics show that tertiary, high molecular-weight polymers can serve as effective additives for improving the performance of low bandgap polymer solar cells.
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [1]
  1. Stony Brook Univ., NY (United States). Dept. of Materials Science and Chemical Engineering
  2. Argonne National Lab. (ANL), Argonne, IL (United States). X-ray Science Division
  3. Brookhaven National Lab. (BNL), Upton, NY (United States). Center for Functional Nanomaterials (CFN)
Publication Date:
Grant/Contract Number:
AC02-06CH11357; SC0012704
Accepted Manuscript
Journal Name:
Advanced Energy Materials
Additional Journal Information:
Journal Volume: 5; Journal Issue: 15
Research Org:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org:
National Science Foundation (NSF); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
25 ENERGY STORAGE; 36 MATERIALS SCIENCE; low bandgap polymer solar cells; ternary blends; polymer additives; interfacial tension; crystallinity
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1456288