Insights into the Influence of Work Functions of Cathodes on Efficiencies of Perovskite Solar Cells. Issue 19 (30th March 2017)

• Record Type: Journal Article
• Authors: Yue, Shizhong; Lu, Shudi; Ren, Kuankuan; Liu, Kong; Azam, Muhammad; Cao, Dawei; Wang, Zhijie; Lei, Yong; Qu, Shengchun; Wang, Zhanguo
• Is Part Of: Small. Volume 13:Issue 19(2017)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-03-30
• Subjects: band bending -- buffer metal -- perovskite solar cells -- work function; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.201700007
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract : Though various efforts on modification of electrodes are still undertaken to improve the efficiency of perovskite solar cells, attributing to the large scope of these methods, it is of significance to unveil the working principle systematically. Herein, inverted perovskite solar cells based on indium tin oxide (ITO)/poly(3, 4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/CH3 NH3 PbI3 /phenyl‐C61‐butyric acid methyl ester (PC61 BM)/buffer metal/Al are constructed. Through the choice of different buffer metals to tune work function of the cathode, the contact nature of the active layer with the cathode could be manipulated well. In comparison with the device using Au/Al as the electrode that shows an unfavorable band bending for conducting the excited electrons to the cathode, the one with Ca/Al presents a dramatically improved efficiency over 17.1%, ascribed to the favorable band bending at the interface of the cathode with the active layer. Details for tuning the band bending and the corresponding charge transfer mechanism are given in a systematic manner. Thus, a general guideline for constructing perovskite photovoltaic devices efficiently is provided. Abstract : A systematic investigation on the impact of the work function of the cathode on the performance of inverted structure perovskite solar cells is provided. Lowering the work function of the cathode largely improves performance, including promoting the separation and conduction of charge carriers and even increasing the generation rate of excitons.