Eco-friendly all-inorganic CsPbX3 (X = Cl, Br, and I) perovskite nanocrystals in pyrophyllite for bright white light-emitting diodes

Abstract

Colloidal lead halide perovskite nanocrystals (NCs) have recently emerged as versatile photonic sources. However, their performance stability has been far from the requirements, and this type of material is toxic to the environment after degradation. In this paper, a hot injection strategy was used to prepare a CsPbX3 perovskite NC solution, wherein the photoluminescence quantum yield (PLQY) of CsPbBrI2 reached 78% and that of CsPbBr3 was 63%. Then, CsPbX3 NCs are successfully adsorbed on natural layered mineral pyrophyllite for improving heat, light, and water stability. Monodispersed CsPbX3 NCs are evenly distributed on the surface of the pyrophyllite sheet in a high-density manner, which possibly originates from the electrostatic attraction effect of abundant anions on the surface of pyrophyllite to CsPbX3 NCs. In a series of CsPbX3@pyrophyllite nanocomposites prepared, the PLQYs of green-emitting CsPbBr3 and red-emitting CsPbBrI2 were 47% and 29%, respectively. The materials were employed to fabricate white light-emitting diodes (WLEDs) with a wide color gamut of 117%. Importantly, because of the swelling and cation-adsorbent properties of pyrophyllite, the dissolution of lead in water was greatly reduced, which plays a certain role in ecological protection.