Despite having long excited carrier lifetimes and high mobilities in hybrid halide perovskite materials, conventional (n-i-p) devices exhibit significant interfacial nonradiative recombination losses that are little understood but limit the radiative efficiency and the overall open-circuit potential. In this Letter, we reveal that the process of spiro-OMeTAD coating on perovskite gives rise to buried defect states, which are detrimental to the devices’ operational stability. We subsequently report a method to passivate these deleterious buried defect states by atomic layer deposition of Al2O3 through controlled precursor dosages on fully functional devices. The process results in notable improvements in the overall device performance, but the underlying root-cause analysis is what we essentially aimed to elucidate here. The reported passivation technique results in (a) an increase in the efficiency primarily due to an increase of V OC by ∼60–70 mV and consequently (b) enhanced photoluminescence and higher electroluminescence quantum efficiency and (c) overall device operational (MPPT) stability under ambient and, exclusively, even under high vacuum (>300 h) conditions, which is otherwise challenging.

High-throughput fabrication of metal oxide thin films is always a bottleneck for solution-processed perovskite solar cells. Here, we report a rapid photonic curing process, with a well-controlled train of short light pulses, to develop bilayer (colloidal and blocking layer) SnO 2 thin films used as electron transport layers in perovskite ((FA 0.83 MA 0.17 ) 0.95 Cs 0.05 PbI 2.5 Br 0.5 , 1.62 eV band gap) photovoltaic devices (n−i−p architecture) with an optimized efficiency of 21.1% alongside good ambient and operational (MPPT) stability. The strong dependency of the photonic curing pulse parameters on device properties is investigated, and we established a corroboration between the chemical properties of the as-cured SnO 2 and the optoelectronic performance of the devices and the interface quality. Furthermore, we show that the futile removal of the chloride species in photonically cured SnO 2 is an added advantage against the thermally annealed ones regarding charge transport and lower interfacial recombination. Furthermore, the process is impeccably scaled up to demonstrate a series-connected minimodule (16 cm 2 ) with 18.2% efficiency.

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