Interfacial TiO2 atomic layer deposition triggers simultaneous crystallization control and band alignment for efficient CsPbIBr2 perovskite solar cell.

We present that atomic layer deposition (ALD) of TiO 2 thin layer on SnO 2 electron transport layer (ETL) could simultaneously boost the crystallization control of CsPbIBr 2 absorber film and band alignment of all-inorganic perovskite solar cell (PSC). The former awards the desired CsPbIBr 2 film characterized by high crystallinity, weak halide phase separation, as well as extremely uniform- and large-sized grains. And, the latter brings a cascade pathway for electron extraction and transport in the cell. Such combined morphology tailoring and interface engineering are extremely beneficial to suppress both bulk recombination and interfacial recombination of charge carrier. As a result, the cell' efficiency can be boosted from 6.11% to 9.31%, which is beyond all the pure CsPbIBr 2 -based PSCs reported to date. Therefore, our works highlight the dual functions of ALD-processed TiO 2 interfacial layer in processing high-performance all-inorganic PSC. Atomic layer deposition (ALD) of TiO 2 thin layer on SnO 2 electron transport layer could simultaneously boost the crystallization control of CsPbIBr 2 absorber film and band alignment of all-inorganic perovskite solar cell. Thus, the cell efficiency can be boosted from 6.11% to the record-high value of 9.31%. Image 1 • ALD-processed TiO 2 on SnO 2 ETL triggers dual functions of crystallization control and band alignment in CsPbIBr 2 PSC. • Crystallization control enables high crystallinity, weak phase separation, and uniformly large-sized grains in CsPbIBr 2 film. • Band alignment facilitates a cascade pathway for electron extraction and transport. • The dual functions of TiO 2 thin layer boost efficiency of pure CsPbIBr 2 -based cell to the record-high value of 9.31%. [ABSTRACT FROM AUTHOR]