Two-Step Close-Space Vapor Transport of MAPbI3 Solar Cells: Effects of Electron Transport Layers and Residual PbI2
Date
2022-09-11
Journal Title
Journal ISSN
Volume Title
Publisher
ACS Applied Energy Materials
Abstract
The effect of the electron transport layer (ETL) on the growth of methylammonium lead iodide (MAPbI3) thin films by two-step close-space vapor transport (CSVT) is reported. Nanocrystalline CdS, as well as amorphous SnO2 and C60, were selected as ETLs on indium tin oxide-coated glass substrates prior to two-step CSVT. The ETL affected the PbI2 growth, leading to different morphological and crystallographic properties. These differences carried over through the methylammonium iodide reaction to the MAPbI3 phase, but compact films with a reasonable morphology could be made on each ETL. The ETL also affected the PbI2-to-MAPbI3 reaction rate. Solar cells processed on each ETL showed a low level of residual PbI2 was important for good photovoltaic conversion efficiency (PCE). The PCEs were similar on average, but trade-offs in J–V parameters depended on the ETL selection. When films on each ETL were reacted beyond an optimal PbI2 residual content, solar cells had lower performance driven by decreases in different J–V parameters. The ETL also had practical effects on J–V performance, namely, hysteresis and air stability. The hysteresis of solar cells on C60 was much less than on SnO2 and CdS. However, the solar cells with C60 ETLs were not stable in air, exhibiting FF and Jsc losses in as little as 15 min of air exposure, while those made on the other ETLs were stable for hours. Thus, the choice of ETL for two-step CSVT affects the growth of PbI2 and its reaction to MAPbI3, but interfacial chemistry considerations and effects on current and atmospheric stability appear to be more important for device performance and yield.
Description
This document is the Accepted Manuscript version of a Published Work that appeared in final form in ACS Applied Energy Materials, copyright © 2022 American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acsaem.2c01468.
This article will be embargoed until 09/11/2023.
Keywords
all-vapor processing, close-space vapor transport, lead halide perovskite solar cells, methylammonium lead iodide, electron transporting layer, extent of reaction, residual lead iodide, affordable and clean energy
Citation
Kuba, Austin G., Alexander J. Harding, Raphael J. Richardson, Brian E. McCandless, Ujjwal K. Das, Kevin D. Dobson, and William N. Shafarman. “Two-Step Close-Space Vapor Transport of MAPbI3 Solar Cells: Effects of Electron Transport Layers and Residual PbI2.” ACS Applied Energy Materials 5, no. 9 (September 26, 2022): 10731–41. https://doi.org/10.1021/acsaem.2c01468.