A Compact Electron Transport Layer Using a Heated Tin‐Oxide Colloidal Solution for Efficient Perovskite Solar Cells. Issue 4 (5th January 2022)

• Record Type: Journal Article
• Authors: Meng, Juan; Röhr, Jason A.; Wang, Hang; Sartor, B. Edward; Song, Dandan; Katzenberg, Adlai; Modestino, Miguel A.; Xu, Zheng; Kong, Jaemin; Taylor, André D.
• Is Part Of: Solar RRL. Volume 6:Issue 4(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-01-05
• Subjects: aqueous colloidal solutions -- interface -- perovskite solar cells -- SnO2 electron transport layers -- thin films; Solar energy -- Periodicals; Photovoltaic power generation -- Periodicals; Solar energy -- Research -- Periodicals; Photovoltaic power generation -- Research -- Periodicals; Periodicals; 333.7923
• DOI: 10.1002/solr.202100794
• Languages: English
• ISSNs: 2367-198X

Abstract

Abstract : Tin dioxide is a frequently reported electron transporting material for perovskite solar cells (PSCs) that yields high‐performance devices and can be solution processed from aqueous colloidal solutions. While being very simple to process, electron transport layers deposited in this manner often lead to nonuniform film morphology, significantly affecting the morphology of the subsequent perovskite layer, lowering the overall device performance. Herein, it is shown that heating the SnO2 colloidal solution (70 °C) results in compact SnO2 films with increased surface coverage and fewer gaps in the SnO2 film. Such films possess threefold higher lateral electrical conductivity than those obtained from room‐temperature solutions. The narrow gaps in the SnO2 film also reduce the chances of direct contact between the indium tin oxide electrode and the perovskite layer, yielding better contact with less voltage loss. The improved SnO2 surface coverage induces larger perovskite grains (≈565 nm) than those prepared from the room‐temperature solution (≈273 nm). Finally, using these compact SnO2 layers, efficient and stable PSCs that retain ≈85% of the initial power conversion efficiency of 20.67% after 100 h of maximum power point tracking are demonstrated. Abstract : Heating colloidal tin oxide solutions changes the particle size distribution from bimodal to unimodal. This mitigates agglomerates, resulting in uniform, compact, and gap‐free SnO2 electron transport layers. Processing perovskite layers on top results in films with reduced grain boundaries and fewer defects, along with improved perovskite/SnO2 interfaces. This facile process results in significantly enhanced perovskite solar cell performance.