Morphological stabilization by supramolecular perfluorophenyl-C 60 interactions leading to efficient and thermally stable organic photovoltaics
Journal
Advanced Functional Materials
Journal Volume
24
Journal Issue
10
Pages
1418-1429
Date Issued
2014
Author(s)
Liao, M.-H.
Tsai, C.-E.
Lai, Y.-Y.
Cao, F.-Y.
Wu, J.-S.
Hsu, C.-S.
Liau, I.
Cheng, Y.-J.
Abstract
A new PC 61 BM‐based fullerene, [6,6]‐phenyl‐C 61 butyric acid pentafluorophenyl ester (PC 61 BP F ) is designed and synthesized. This new n‐type material can replace PC 61 BM to form a P3HT:PC 61 BP F binary blend or serve as an additive to form a P3HT:PC 61 BM:PC 61 BP F ternary blend. Supramolecular attraction between the pentafluorophenyl group of PC 61 BP F and the C 60 cores of PC 61 BP F /PC 61 BM can effectively suppress the PC 61 BP F /PC 61 BM materials from severe aggregation. By doping only 8.3 wt% PC 61 BP F , device PC 61 BP F 651 exhibits a PCE of 3.88% and decreases slightly to 3.68% after heating for 25 h, preserving 95% of its original value. When PC 61 BP with non‐fluorinated phenyl group is used to substitute PC 61 BP F , the stabilizing ability disappears completely. The efficiencies of PC 61 BP651 and PC 61 BP321 devices significantly decay to 0.44% and 0.11%, respectively, after 25 h isothermal heating. Most significantly, this strategy is demonstrated to be effective for a blend system incorporating a low band‐gap polymer. By adding only 10 wt% PC 61 BP F , the PDTBCDTB: PC 71 BM‐based device exhibits thermally stable morphology and device characteristics. These findings demonstrate that smart utilization of supramolecular interactions is an effective and practical strategy to control morphological evolution.
SDGs
Type
journal article