Heintges Gaël H L, Leenaers Pieter J, Janssen René A J
Molecular Materials and Nanosystems , Institute for Complex Molecular Systems , Eindhoven University of Technology , P.O. Box 513 , 5600 MB Eindhoven , The Netherlands . Email:
Institute for Materials Research (IMO-IMOMEC) , Design & Synthesis of Organic Semiconductors (DSOS) , Hasselt University , Agoralaan, 3590 Diepenbeek , Belgium.
J Mater Chem A Mater. 2017 Jul 14;5(26):13748-13756. doi: 10.1039/c7ta01740e. Epub 2017 Jun 8.
The effects of cold and hot processing on the performance of polymer-fullerene solar cells are investigated for diketopyrrolopyrrole (DPP) based polymers that were specifically designed and synthesized to exhibit a strong temperature-dependent aggregation in solution. The polymers, consisting of alternating DPP and oligothiophene units, are substituted with linear and second position branched alkyl side chains. For the polymer-fullerene blends that can be processed at room temperature, hot processing does not enhance the power conversion efficiencies compared to cold processing because the increased solubility at elevated temperatures results in the formation of wider polymer fibres that reduce charge generation. Instead, hot processing seems to be advantageous when cold processing is not possible due to a limited solubility at room temperature. The resulting morphologies are consistent with a nucleation-growth mechanism for polymer fibres during drying of the films.
对于基于二酮吡咯并吡咯（DPP）的聚合物，研究了冷热加工对聚合物 - 富勒烯太阳能电池性能的影响。这些聚合物是专门设计和合成的，在溶液中表现出强烈的温度依赖性聚集。由交替的DPP和寡噻吩单元组成的聚合物，被线性和第二位支化的烷基侧链取代。对于可以在室温下加工的聚合物 - 富勒烯共混物，与冷加工相比，热加工不会提高功率转换效率，因为在升高温度下增加的溶解度导致形成更宽的聚合物纤维，从而减少电荷产生。相反，当由于室温下溶解度有限而无法进行冷加工时，热加工似乎具有优势。所得形态与薄膜干燥过程中聚合物纤维的成核 - 生长机制一致。
