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Polymer/Si Heterojunction Hybrid Solar Cells with Rubrene:DMSO Organic Semiconductor Film as an Electron-Selective Contact C

Yang, Linlin, Chen, Jianhui, Ge, Kunpeng, Guo, Jianxin, Duan, Qingchun, Li, Feng, Xu, Ying, Mai, Yaohua
Journal of physical chemistry 2018 v.122 no.41 pp. 23371-23376
dimethyl sulfoxide, electric potential, physical chemistry, polymers, semiconductors, silicon, solar cells, solar energy, solvents
An organic semiconductor composite thin film, 5,6,11,12-tetraphenylnaphthacene:dimethyl sulfoxide (rubrene:DMSO), is fabricated by dissolving rubrene powder into the DMSO solvent to form the precursor solution using spin-coating technology. It is found that the work function of the rubrene:DMSO thin film is 3.84 eV, which is lower than the electron affinity of the n-Si (4.05 eV), leading to the efficacy of the rubrene:DMSO film as an electron-selective contact to tailor energy band structures in the current dopant-free silicon (Si)-based heterojunction solar cells. When the rubrene:DMSO film is introduced to the poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/Si heterojunction hybrid solar cells to form an organic/c-Si/organic structure, the open circuit voltage and fill factor of the solar cell device present significant improvement, leading to a relative increase of 27% in power conversion efficiency. This is ascribed to the reduction of recombinative and resistive losses at the rear side of the device, which is contributed by an efficient electron-selective rubrene:DMSO contact. This all-organic carrier-selective contact promises to revolutionize by providing inexpensive, lightweight, and capable ubiquitous components that are coated onto ultrathin c-Si solar cells.