Preparation of all-inorganic perovskite quantum dots-polymer composite for white LEDs application

In recent years, all-inorganic lead halide perovskite CsPbX3 (X = Cl, Br, I) nanocrystals as kinds of new luminescent materials have attracted more and more attentions because of their size tunable emission wavelength, narrow emission peak, high luminous efficiency and good air stability. Herein we have synthesized all-inorganic halide perovskite nanocrystals by hot-injection method and anion exchange reaction, achieving the whole visible light region from 410 to 700 nm with narrow spectral in the range of 15-40 nm. Moreover, a white light emitting diode (WLED) was constructed by stacking CsPbBr3 QDs-ethyl acetate composite film and CaSrAlN3:Eu2+-poly (methyl methacrylate) composite film on the blue LED chip, displaying the ideal white light with the chromaticity coordination at (0.3379, 0.3432) and the color temperature of 5261 K. Because of the deep traps resulted from partial oxidation at the QDs' surface under large excitation light intensity, the WLED is not stable enough to work at a high operation current, but it can work steadily under a relatively lower operation current.