| Summary: | 碩士 === 國立交通大學 === 材料科學與工程學系所 === 106 === In this study, we employed a simple concept of ternary blend system for organic solar cell. Through blending small molecule (SM-4OMe) which has comple-mentary absorption spectrum into the host binary system (PTB7-TH and PC71BM), we successfully broadened the range of absorption spectrum and obtained higher efficiency of harvesting sunlight. We synthesized SM-4OMe with the same benzodithiophene (BDT) unit as the donor of PTB7-TH, which leaded to good morphology compatibility by blending PTB7-TH, SM-4OMe and PC71BM together to form desired packing orientation in the ternary blend films. Moreover, fluorescence resonance energy transfer took place between PTB7-TH and SM-4OMe, generating more carriers to diffuse to the interface of donor and acceptor so that the higher short-circuit current was collected by electrodes and eventually the PCE was optimized. The best PCE of 10.3% was obtained by incorporating PTB7-TH:SM-4OMe:PC71BM at weight ratio 0.9:0.1:1.5 in chlorobenzene, processed with 2vol% 1,8-Diiodooctane (DIO). We only added slight amount of SM-4OMe to form ternary blend films for ensuring the desired packing orientation for the better carrier transport. The result showed the PCE for the single junction organic photovoltaics could be successfully enhanced by a facile ternary blend.
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