![]() Furthermore, ionic nature presents significant drawback as the PeNCs are extremely sensitive to environmental conditions, particularly to exposure to moisture, oxygen-rich atmosphere, and light. However, their inherent instability and degradation of the PLQY over time limit further advance of PeNCs in practical applications. The newly emerged lead halide perovskite nanocrystals (PeNCs) have drawn extensive attention owing to their tunable optical properties, narrow emission bandwidth, and high photoluminescence quantum yield (PLQY) and were successfully used in a range of optoelectronic devices such as photodetectors and light-emitting diodes (LEDs). The maximum current efficiency observed in core/shell NC LED is 19.75 cd A -1 and the external quantum efficiency of 8.1%, which are approximately four times and approximately eight times higher, respectively, compared to core-only devices. The use of these green-emitting core/shell FAPbBr 3/CsPbBr 3 NCs is demonstrated in light-emitting diodes (LEDs) and significant enhancement of their performance is achieved compared to core only FAPbBr 3-LEDs. The enhanced properties are attributed to overgrowth of FAPbBr 3 with all-inorganic CsPbBr 3 shell, which acts as a protective layer and enables effective passivation of the surface defects. The core/shell perovskites have enhanced optical stability under ambient conditions (70 d) and under ultraviolet radiation (50 h). The formed FAPbBr 3/CsPbBr 3 NCs have photoluminescence in the visible range 460–560 nm with narrow emission linewidth (20 nm) and high optical quantum yield, photoluminescence quantum yield (PLQY) up to 93%. Here the development of a novel synthesis method is reported for monodispersed PeNCs coated with all inorganic shell of cesium lead bromide (CsPbBr 3) grown epitaxially on the surface of formamidinium lead bromide (FAPbBr 3) NCs. However, their environmental instability remains to be addressed to enable their advancement into industry. Lead halide perovskite nanocrystals (PeNCs) are promising materials for applications in optoelectronics.
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