Strategic Halogenation Enabling High-Performance Small-Molecule Based Organic Solar Cells through Morphology Control
발표자
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초록
내용
Morphology is a key parameter that enables high-performance organic solar cells. A series of benzodithiophene (BDT)-based active materials with specific halogen atom substitutions were developed to control the morphology. The effect of these halogen substitutions on the bulk-heterojunction (BHJ) architecture is demonstrated through microstructure analyses (GIWAXS). When blended with PC71BM, the chlorine substituted one (BDTID-Cl) exhibits a well-mixed morphology and interpenetrating networks, allowing efficient charge transportation. This controlled morphology helps achieve outstanding performance with 10.5% power conversion efficiency (PCE) and the highest fill factor of 78.0% in the single-junction small molecule based organic solar cells (SM-SCs). It can also be applied to two-terminal (2T)-tandem solar cells, resulting in an excellent PCE of 15.1% through complementary absorption in the 2T-tandem solar cells incorporating the SM-SCs.