Low‐Temperature Solution‐Processed ZnO Electron Transport Layer for Highly Efficient and Stable Planar Perovskite Solar Cells with Efficiency Over 20%

Abstract

ZnO is considered as a potential electron transport layer (ETL) in solar cells due to its high charge carrier mobility and low‐temperature processability. However, it is challenging to obtain highly efficient and stable perovskite solar cells (PSCs) using low‐temperature ZnO ETL due to the poor chemical compatibility between ZnO and perovskite films. Hence, proper surface passivation strategies of ZnO ETL are developed to enhance the ZnO/perovskite interface stability for highly efficient PSCs. In this study, low‐temperature TiOx post‐treatment is performed to passivate the ZnO surface, suppress the interface charge recombination, and stabilize the ZnO/perovskite interface. The fullerene treatment is further applied to enhance the electron transfer from perovskite to ZnO and reduce the hysteresis behavior. Finally, high‐performance PSCs with an efficiency of over 20% and improved stability are achieved.

Deep‐Ultraviolet Photoactivation‐Assisted Contact Engineering Toward High‐Efficiency and Stable All‐Inorganic CsPbI2Br Perovskite Solar Cells

“…To date, solar cells based on halide perovskites have developed rapidly with their power conversion efficiency (PCE) reaching a record of 25.2%, which is far beyond the threshold of solar cells commercialization. Thus, perovskite solar cells (PSCs) have been considered as new photovoltaic materials for next‐generation energy technology . In addition, organic–inorganic perovskites have been widely used in light‐emitting diodes (LEDs), photodetectors, and transistors due to their efficient ambipolar transport and striking light absorption properties .…”

Enhancing Perovskite Solar Cell Performance through Surface Engineering of Metal Oxide Electron-Transporting Layer

“…To further investigate the photophysical properties of the thin films, steady-state photoluminescence (PL) and time-resolved PL (TR-PL) measurements of perovskite thin films were further investigated. The perovskite film based on TiCl 4 -treated TiO 2 ETL showed larger PL intensity decay compared to the pristine TiO 2 -based perovskite film ( Figure 6), indicating a faster charge transfer process between TiO 2 and perovskite thin films [30]. Furthermore, the PL lifetimes of perovskite films on glass were also measured ( Figure 7).…”

“…Hence, various interface transporting layers have been studied. Among them, metal oxides (e.g., ZnO, SnO 2 , and TiO 2 ) have been widely investigated as electron-transporting layers (ETLs) in PSCs [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37], particularly TiO 2 ETL. The surface and electronic properties of TiO 2 play important roles in determining the final device performance, including power conversion efficiency (PCE), hysteresis behavior, and stability [20,38,39].…”

Recent progress of two‐dimensional lead halide perovskite single crystals: Crystal growth, physical properties, and device applications

“…In recent years, great progress has been made in the preparation and application of 2D perovskite materials, such as the simple spin‐coating method to prepare various perovskite films for photovoltaics, photodetectors, and other applications 54–60 . However, the resulting polycrystalline film has a stability problem and is easily eroded by oxygen and humidity (Figure 1B).…”