Highly stable all-inorganic CsPbBr3 perovskite solar cells based on pulsed laser deposition

Abstract

In the highly efficient n-i-p structure of perovskite solar cells (PSCs), organic material Spiro-OMeTAD is usually used as the hole transport layer (HTL). However, its high hygroscopicity and thermal instability seriously limit its commercial application. In contrast, nickel oxide (NiOx) is a promising alternative due to its wideband gap, low cost, and high stability. By comparing with traditional spin coating, pulsed laser deposition (PLD) can produce relatively compact films and avoid the damage of solvent evaporation on the morphology and crystal quality, thus improving the device stability. This work introduces PLD to prepare CsPbBr3 and NiOx thin films to obtain highly stable all-inorganic CsPbBr3-based PSCs. Carrier dynamics are studied via electrochemical measurements and transient absorption spectroscopy. The power conversion efficiency of the all-inorganic CsPbBr3-based PSCs with NiOx HTL can be improved to 5.47% under optimum thickness and annealing temperature. It is revealed that the thermal stability is significantly enhanced, where unencapsulated all-inorganic CsPbBr3 PSCs specifically can maintain 95% of initial efficiency for 1200 h under the condition of 85 °C and 30% relative humidity.