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Two-dimensional (2D) organic–inorganic hybrid metal halide perovskites (MHPs) are promising as semiconducting light-emitting materials due to improved environmental stability and unique optical properties, compared with three-dimensional MHPs. However, toxic Pb and relatively low photoluminescence quantum yield (PLQY) limit the potentials of these 2D lead halides in solid-state lighting. Herein, we report a series of F-doped, 2D zinc halide-layered perovskites based on phenylethylamine (PEA), PEA2ZnFxCl4–x, which exhibits efficient white light and the highest PLQY of 21.02% at x = 0.40, seven times higher than that of non-F doping samples for 2D hybrid white-light-emitting MHPs. Steady-state and temperature-dependent optical measurements verify that the white-emission arose from self-trapped excitons and highlight the significant effects of F-doping and defect passivation on efficient photoluminescence. Especially, F-doped 2D zinc halide perovskites show ultrahigh stability with negligible degradation for 1000 h at 80 °C. This work paves an avenue to designing efficient and stable single-component white-light-emitting diodes in solid-state lighting. [ABSTRACT FROM AUTHOR]

The fabrication of α-FAPbI 3 perovskite films usually requires high temperature annealing above 150 °C, and the residual tensile strain in the films seriously affects the stability of α-FAPbI 3 by converting to δ-phase FAPbI 3 . Here, we use MASCN surface treatment of FAPbI 3 films to induce a rotation of the coplanar octahedron [PbI 6 ] 4- to the metric octahedron for the strong interaction of SCN - with Pb 2+ , converting δ-FAPbI 3 into α-FAPbI 3 highly crystalline films at room temperature. The optimized FAPbI 3 films have high stability due to releasing residual tensile strains after MASCN treatment. The efficiency of the MASCN-treated unannealed FAPbI 3 PSC is 19.03%, while the optimized FAPbI 3 annealed at 100 °C shows a maximum PCE of 21.95% on a small area. The solar cell stability for humidity, light, and thermal stability are significantly improved. The MASCN treated FAPbI 3 achieves a PCE of 15.32% on a PSC module with an effective area of 9.6 cm 2 and maintains an initial efficiency of 94.1% after 100 days of ageing at 85 °C and 85% humidity.

SnO 2 is widely used as the electron transport layer (ETL) in n-i-p perovskite solar cells. However, the deep-level defects at the interface between SnO 2 and the perovskite film will lead to energy loss, reducing the open-circuit voltage. Therefore, the interface optimization is essential to raise the efficiency and enhance the stability of perovskite solar cells. In this work, we introduce NH 4 F into the SnO 2 electron transport layers, and the optimized SnO 2 films reduce the interface defect density, improve the charge extraction, and reveal a better energy-level arrangement. Compared to the conventional SnO 2 perovskite solar cell, the average V oc is improved by 70 mV with the champion efficiency up to 22.12%. Moreover, the unencapsulated F-doped SnO 2 perovskite solar cells show better thermal stability (maintained 86.2%) and humidity stability (maintained 80.8%) after 35 days.