Full-Spectral Fine-Tuning Visible Emissions from Cation Hybrid Cs_1–<i>m</i>FA<i>_m</i>PbX₃ (X = Cl, Br, and I, 0 ≤ <i>m</i> ≤ 1) Quantum Dots

Abstract

Full-color visible emissions are particularly crucial for applications in displays and lightings. In this work, we developed a facile room-temperature ligand-assisted supersaturated recrystallization synthesis of monodisperse, cubic structure Cs_1–<i>m</i>FA<i>_m</i>PbX₃ (X = Cl, Br, and I or their mixtures Cl/Br and Br/I, 0 ≤ <i>m</i> ≤ 1) hybrid perovskite quantum dots (QDs). Impressively, cation substitution of Cs⁺ by FA⁺ was beneficial in finely tuning the band gap and in exciton recombination kinetics, improving the structural stability, and raising the absolute quantum yields up to 85%. With further assistance of anion replacement, full-spectral visible emissions in the wavelength range of 450–750 nm; narrow full width at half-maxima, and a wide color gamut, encompassing 130% of National Television System Committee television color standard, were achieved. Finally, Cs_1–<i>m</i>FA<i>_m</i>PbX₃-polymer films retaining multicolor luminescence are prepared and a prototype white light-emitting diode device was constructed using green Cs_0.1FA_0.9PbBr₃ and red Cs_0.1FA_0.9Br_1.5I_1.5 QDs as color converters, certainly suggesting their potential applications in the optoelectronics field