Low‐Temperature Processing Methods for Tin Oxide as Electron Transporting Layer in Scalable Perovskite Solar Cells

Abstract

Perovskite solar cell (PSC) technology experiences a remarkably rapid growth toward commercialization with certified efficiency of over 25%, along with the outstanding breakthrough in the development of SnO2. Owing to the wide bandgap, high electron mobility, chemical stability, and low photocatalytic activity, SnO2 has been the rising star to serve as electron transporting layer (ETL). More importantly, the low‐temperature fabrication process (<200 °C) enables SnO2 a promising candidate for the industry, making it compatible with the plastic substrates and large‐scale production, which is crucial for the flexible and scalable devices fabrication. In this review, the processing methods (solution‐based, vacuum‐based, and vapor‐based deposition) of low‐temperature SnO2 (LT‐SnO2) and the pros and cons of them with a focus on their scalability are discussed. Additionally, the morphologies of obtained LT‐SnO2 are investigated to guide the design and performance improvement of devices. The modification strategies to reduce undesired nonradiative recombination and passivate the defects in the bulk or at the interface of LT‐SnO2, influencing the quality of perovskite films, together with the efficiency and stability of cells are summarized. This review is a comprehensive overview of the studies on low‐temperature SnO2 ETL and provides detailed instructions for scalable PSCs.

Dynamic synergy of tin in the electron-transfer layer and absorber layer for advancing perovskite solar cells: a comprehensive review

“…The inability to achieve uniform and defect-free films on flexible substrates limits the scalability and performance of flexible perovskite solar cells. 401 4.1.3. Electron extraction and mobility.…”

Photoexcitation-induced passivation of SnO2 thin film for efficient perovskite solar cells

“…This is in part because the ETLs normally show poor heat transfer and large thermal inertia for passivation under near thermal equilibrium, which makes it challenging to reduce the annealing temperature and time, bringing additional energy costs. Currently, except for thermal annealing at high temperatures for at least 1 h, there is no better way to reduce the annealing temperature of tin oxide films prepared by using the CBD method [ 17 , 18 ]. At the same time, thermal annealing is generally followed by buried interface passivation to further reduce surface defects, which requires additional thermal annealing and complicates the preparation process [ 19 , 20 ].…”