Li-Doped Chemical Bath Deposited SnO₂ Enables Efficient Perovskite Photovoltaics

Abstract

Electron transport layers (ETLs) based on tin oxide (SnO2) get wide attention in planar perovskite solar cells (PSCs), with the merits of high electron mobility and low-temperature fabrication. However, the poor electron extraction ability of SnO2 seriously deteriorates the performance of devices. Herein, we report an optimized strategy for SnO2 films to enhance the carrier transport. The dense and pinhole free ETL films with Li doping are developed by chemical bath deposition. Li-doped SnO2 shows better energy band alignment between ETLs and perovskite layers, which facilitates the electron extraction and reduces recombination loss. On the basis of the above improved performances, the PSCs with Li-doped SnO2 have achieved an improved power conversion efficiency (PCE) over 22%. The unencapsulated devices show excellent stability, and the PCE exhibits almost no change after 800 h storage.

Electron transport layer assisted by nickel chloride hexahydrate for open-circuit voltage improvement in MAPbI3 perovskite solar cells

“…After the introduction of NiCl 2 ·6H 2 O, the intensity of hydroxyl (or oxygen vacancies) decreased significantly, indicating that the oxygen vacancies were effectively passivated. 41 The reduction of oxygen vacancy defects will improve V OC . Therefore, the successful introduction of NiCl 2 ·6H 2 O will considerably improve the ETL.…”

Robust electron transport layers of SnO2 for efficient perovskite solar cells: recent advances and perspectives

“…Wang et al used the CBD method to deposit a tin oxide film on the perovskite light-absorbing layer and used lithium chloride (LiCl) as a dopant to improve the morphology of SnO 2 by controlling the reaction time and pH value. 73 The energy level arrangement and electrical properties of Li-doped ETLs were reported. They found that Li doping can improve electron extraction ability and conductivity.…”

Irreversible phase back conversion of α‐FAPbI3 driven by lithium‐ion migration in perovskite solar cells

“…As the alkali metal is incorporated as an interstitial dopant within the perovskite, it can passivate and immobilize the charged defects, thus enhancing the performance and stability of the PSCs 5,14 . The ETL can also benefit from the migrated Li + ions, as carrier extraction is enhanced by improved interfacial band alignment and conductivity of the ETL 15,16 . Despite the reported beneficial effects of interstitial doping, our recent study unraveled possible detrimental effects that are caused by induced microstrain, particularly for widely used formamidinium lead tri‐iodides (FAPbI 3 ) based perovskites 5 .…”

“…5,14 The ETL can also benefit from the migrated Li + ions, as carrier extraction is enhanced by improved interfacial band alignment and conductivity of the ETL. 15,16 Despite the reported beneficial effects of interstitial doping, our recent study unraveled possible detrimental effects that are caused by induced microstrain, particularly for widely used formamidinium lead tri-iodides (FAPbI 3 ) based perovskites. 5 Thus, we were motivated to study side effects caused by the Li + ion migration in FAPbI 3 PSCs.…”