Tin Oxide Electron‐Selective Layers for Efficient, Stable, and Scalable Perovskite Solar Cells

Abstract

Perovskite solar cells (PSCs) have become a promising photovoltaic (PV) technology, where the evolution of the electron‐selective layers (ESLs), an integral part of any PV device, has played a distinctive role to their progress. To date, the mesoporous titanium dioxide (TiO2)/compact TiO2 stack has been among the most used ESLs in state‐of‐the‐art PSCs. However, this material requires high‐temperature sintering and may induce hysteresis under operational conditions, raising concerns about its use toward commercialization. Recently, tin oxide (SnO2) has emerged as an attractive alternative ESL, thanks to its wide bandgap, high optical transmission, high carrier mobility, suitable band alignment with perovskites, and decent chemical stability. Additionally, its low‐temperature processability enables compatibility with temperature‐sensitive substrates, and thus flexible devices and tandem solar cells. Here, the notable developments of SnO2 as a perovskite‐relevant ESL are reviewed with emphasis placed on the various fabrication methods and interfacial passivation routes toward champion solar cells with high stability. Further, a techno‐economic analysis of SnO2 materials for large‐scale deployment, together with a processing‐toxicology assessment, is presented. Finally, a perspective on how SnO2 materials can be instrumental in successful large‐scale module and perovskite‐based tandem solar cell manufacturing is provided.

Up-Scalable Fabrication of SnO2 with Multifunctional Interface for High Performance Perovskite Solar Modules

“…High-quality and advanced fabrication techniques of SnO 2 films not only help achieve a high efficiency in lab-scale, but also promote the development of perovskite solar modules (PSMs) [ 28 ]. To date, the record mini-module efficiency of PSMs is over 18.6% with a module area of ~ 30 cm 2 [ 29 ].…”

Ligand-bridged charge extraction and enhanced quantum efficiency enable efficient n–i–p perovskite/silicon tandem solar cells

“…11,18,19 This temperature requirement excludes the applicability of this ESL stack for tandems built onto highperformance SHJ bottom cells, 20 whose temperature processing window is o250 1C due to their amorphous-silicon passivated surfaces. Thin films of tin oxide nanoparticles (np-SnO x ) are also increasingly used as an ESL on PSCs, 21 and these are usually deposited at lower temperatures (o200 1C). 22,23 However, np-SnO x ESLs are solution-processed.…”

Simultaneous Modulation of Interface Reinforcement, Crystallization, Anti‐Reflection, and Carrier Transport in Sb Gradient‐Doped SnO2/Sb2S3 Heterostructure for Efficient Photoelectrochemical Cell

“…[ 22–25 ] In fact, SnO 2 owns numerous advantages for PEC‐WS application when compared with TiO 2 , such as i) lower conduction band states for accelerating the electron injection; ii) much higher electron mobility (higher than 400 cm 2 V −1 S −1 ) for enhancing the electron extraction/transport and decreasing the carrier recombination; iii) anti‐reflection effect at visible region for allowing more photons reach to the light absorber; iv) lower crystallization temperature for reducing the fabrication cost; v) excellent lattice match with conductive glass of FTO or ITO. [ 26–29 ] To sum up, SnO 2 is a superior ideal inorganic electron extraction material for PEC‐WS system.…”