Random terpolymers are developed by incorporating small portions of benzodithiophene into a highly crystalline copolymer of terthiophene and difluorobenzothiadiazole, BDT-Th0. The bulk-heterojunction (BHJ) of the copolymer BDT-Th0 is formed by a process of rapid solid–liquid phase demixing of polymer crystallites, which results in an irregular and an unclear phase separation with a large polymer aggregation. By contrast, the random terpolymer BDT-Th10, which was prepared using a 10% feed molar ratio of a benzodithiophene moiety, shows a slower and a gradual formation of the polymer packing structures without substantial agglomeration from loosely packed pseudocrystallites in precursor solution. This results in an optimal BHJ morphology with an appropriate phase separation and improved domain purity. BDT-Th10 achieves a high solar cell efficiency of 7.74% by successfully reproducing the optimized BHJ morphology of small cells into 58.5 cm²-sized modules with 350 nm film thickness, whereas the copolymer shows an irreproducible property with a much decreased efficiency of 4.37%. This result is among the highest efficiencies of high-performance large-area PSC modules with such a thick active film.

中文翻译：

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高效的大面积有机光伏模块，具有使用随机三元共聚物供体的350 nm厚的有源层

通过将一小部分苯并二噻吩掺入对苯二噻吩和二氟苯并噻二唑的高结晶共聚物BDT-Th0中，可以开发出无规三元共聚物。共聚物BDT-Th0的本体-异质结（BHJ）是通过聚合物微晶的快速固-液相分解过程形成的，这会导致不规则且不清楚的相分离以及大量的聚合物聚集。相比之下，使用苯甲二噻吩部分的进料摩尔比为10％制备的无规三元共聚物BDT-Th10，显示出聚合物填充结构的缓慢缓慢形成，并且没有前驱体溶液中松散堆积的假晶体的大量团聚。这导致最佳的BHJ形态，具有适当的相分离和改善的域纯度。膜厚为350 nm的²尺寸模块，而该共聚物表现出不可复制的性能，效率降低了4.37％。这种结果是具有如此厚的有源膜的高性能大面积PSC模块的最高效率。