浴銅靈摻雜入富勒烯應用於鈣鈦礦太陽能電池電子傳輸層之研究

Abstract

本研究中利用摻雜浴銅靈(2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline, bathocuproine, BCP)於富勒烯衍生物( [6,6]phenyl-C61-butyric acid methyl ester, PC61BM)中，成功提升鈣鈦礦太陽能電池元件光電轉換效率。經由BCP的摻雜能減少電子傳輸層(Electron Transport Layer, ETL)薄膜缺陷及降低載子再結合的機率，進而提高元件之開路電壓，而短路電流和填充因子的提升則來自於較佳的界面相容性，當摻雜0.5wt% BCP於PC61BM作為電子傳輸層時，元件效率可達14.3%，相較於未摻雜時有52%的提升率。 我們以ITO/PEDOT:PSS/CH3NH3PbI3-xClx/PC61BM:BCP/Ag作為元件結構主體，使用國家同步輻射研究中心(NSRRC)之低掠角小角度X光散射(GISAXS)進行電子傳輸層團簇大小研究，輔以原子力顯微鏡(AFM)、掃描電子顯微鏡(SEM)、光激發螢光光譜儀(PL)、紫外光-可見光光譜(UV-vis)等儀器，用以探討影響鈣鈦礦太陽能電池元件轉換效率的成因。

In this study, we doped different amounts of 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline (bathocuproine, BCP) in [6,6]phenyl-C61-butyric acid methyl ester (PC61BM) and successfully improved the power conversion efficiency (PCE) of perovskite photovoltaic device. With the incorporation of BCP, we found that it can not only ameliorate the film formation property of PCBM and the interfacial contact but facilitate the charge transport and separation at the interface through effectively passivating the surface trap states of perovskite as well. These physical, optical, morphological, and electronic improvements result in higher open-circuit voltage (Voc), short-circuit current density (Jsc), and fill factor (FF). Therefore, the PCE is improved from 9.4% to 14.3%. The planar-heterojunction structure of the photovoltaic devices having the confugutation ITO/PEDOT:PSS/CH3NH3PbI3-xClx/PC61BM:BCP/Ag. In order to systematically investigate the effect of BCP doping, we use a combination of characterizations, including grazing-incidence small-angle X-ray scattering (GISAXS), atomic force microscopy (AFM), scanning electron microscopy (SEM), photoluminescence (PL) and ultraviolet–visible spectroscopy (UV-vis). We can understand that, as a result, this approach of incorporating small molecule into a fullerene allowed us to effectively tune the morphology of the ETL on the perovskite active layer and resulted in enhanced device efficiency.