Low-Temperature Nb-Doped SnO2 Electron-Selective Contact Yields over 20% Efficiency in Planar Perovskite Solar Cells

• Published in: ACS energy letters 2018-04, Vol.3 (4), p.773-778
• Main Authors: Halvani Anaraki, Elham, Kermanpur, Ahmad, Mayer, Matthew T, Steier, Ludmilla, Ahmed, Taha, Turren-Cruz, Silver-Hamill, Seo, Jiyoun, Luo, Jingshan, Zakeeruddin, Shaik Mohammad, Tress, Wolfgang Richard, Edvinsson, Tomas, Grätzel, Michael, Hagfeldt, Anders, Correa-Baena, Juan-Pablo
• Format: Article
• Language: English
• ISSN: 2380-8195; 2380-8195
• DOI: 10.1021/acsenergylett.8b00055

Low-temperature planar organic–inorganic lead halide perovskite solar cells have been at the center of attraction as power conversion efficiencies go beyond 20%. Here, we investigate Nb doping of SnO2 deposited by a low-cost, scalable chemical bath deposition (CBD) method. We study the effects of doping on compositional, structural, morphological, and device performance when these layers are employed as electron-selective layers (ESLs) in planar-structured PSCs. We use doping concentrations of 0, 1, 5, and 10 mol % Nb to Sn in solution. The ESLs were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, atomic force microscopy, and ultraviolet–visible spectroscopy. ESLs with an optimum 5 mol % Nb doping yielded, on average, an improvement of all the device photovoltaic parameters with a champion power conversion efficiency of 20.5% (20.1% stabilized).