Photonically Cured Solution-Processed SnO2 Thin Films for High- Efficiency and Stable Perovskite Solar Cells and Minimodules

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) SnO2 thin films used as electron transport layers in perovskite ((FA0.83MA0.17)0.95Cs0.05PbI2.5Br0.5, 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 SnO2 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 SnO2 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 cm2) with 18.2% efficiency.

Automated summary

We report a rapid photonic curing process for the fabrication of bilayer SnO2 thin films as electron transport layers in perovskite solar cells. The optimized efficiency of 21.1% and good stability were achieved. The photonic curing pulse parameters were found to significantly affect the device properties, and a correlation was established between the chemical properties of the cured SnO2 and the optoelectronic performance of the devices. The photonically cured SnO2 showed advantages in charge transport and interfacial recombination compared to thermally annealed ones. Furthermore, the process was successfully scaled up to a series-connected minimodule with 18.2% efficiency.