All-Polymer Solar Cell Performance Optimized via Systematic Molecular Weight Tuning of Both Donor and Acceptor Polymers

• DOI: 10.1021/jacs.5b10735
• Publication Date: 2015-12-31T10:53:42Z
• Authors: Nanjia Zhou; Alexander S. Dudnik; Ting I. N. G. Li; Eric F. Manley; Thomas J. Aldrich; Peijun Guo; Hsueh-Chung Liao; Zhihua Chen; Lin X. Chen; Robert P. H. Chang; Antonio Facchetti; Monica Olvera de ...; Tobin J. Marks
• Keywords: Acceptor

The influence of the number-average molecular weight (Mn) on blend film morphology and photovoltaic performance all-polymer solar cells (APSCs) fabricated with donor polymer poly[5-(2-hexyldodecyl)-1,3-thieno[3,4-c]pyrrole-4,6-dione-alt-5,5-(2,5-bis(3-dodecylthiophen-2-yl)thiophene)] (PTPD3T) acceptor poly{[N,N′-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5′-(2,2′-bithiophene)} (P(NDI2OD-T2); N2200) is systematically investigated. Mn effect analysis both PTPD3T N2200 enabled by implementing a polymerization strategy which produces conjugated polymers tunable Mns. Experimental coarse-grain modeling results reveal that systematic variation greatly influences intrachain interchain interactions ultimately degree phase separation evolution. Specifically, increasing for shrinks domain sizes enhances donor–acceptor polymer–polymer interfacial areas, affording increased short-circuit current densities (Jsc). However, greater disorder intermixed feature proliferation accompanying promotes charge carrier recombination, reducing cell fill factors (FF). optimized photoactive layers exhibit well-balanced exciton dissociation transport characteristics, providing 2-fold PCE enhancement versus devices nonoptimal Overall, it shown proper precise tuning Mns critical optimizing APSC performance. In contrast to reports where maximum power conversion efficiencies (PCEs) are achieved highest Mns, present two-dimensional optimization matrix locates "sweet spot" at intermediate polymers. This study provides synthetic methodologies predictably access desired highlights importance components realize full potential