Premium
Side‐Chain Optimization of Phthalimide−Bithiophene Copolymers for Efficient All‐Polymer Solar Cells with Large Fill Factors
Author(s) -
Chen Jianhua,
Qiu Fanglong,
Liao Qiaogan,
Peng Changliang,
Liu Feng,
Guo Xugang
Publication year - 2018
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.201800156
Subject(s) - phthalimide , side chain , polymer , polymer solar cell , copolymer , energy conversion efficiency , materials science , chemical engineering , polymer chemistry , imide , solar cell , chemistry , organic chemistry , optoelectronics , composite material , engineering
A series of phthalimide−bithiophene copolymers with various side‐chains have been used in bulk‐heterojunction all‐polymer solar cells (all‐PSCs) by blending with the well‐known n‐type polymer N2200. Variation in the side‐chains on the bithiophene and N ‐imide groups afforded phthalimide polymers with tunable optoelectrical properties and different self‐assembly characteristics. Optimization of the fabrication conditions for the all‐PSCs resulted in a power‐conversion efficiency (PCE) of 3.77 %, with a remarkable fill factor (FF) of 71.21 % for a cell with an active layer thickness of 100 nm. This FF is one of the highest values for all‐PSCs reported to date. Moreover, a greatly improved PCE of 4.7 %, with a good FF of 61.64 %, was obtained by increasing the film thickness to 120 nm. These results indicate that the FFs of all‐PSCs could approach those of polymer:fullerene cells, if a favorable blend film morphology can be realized and efficient charge‐transport/‐extraction can be achieved. These results demonstrate that phthalimide‐based polymers are promising donor semiconductors for the construction of efficient all‐PSCs and that their side‐chains are critical for performance enhancement, in addition to their polymer backbone.