. Scheme of the all-solid-state ball milling procedure for synthesis of CsPbX₃ NCs (a) and optical image of large-scale red emission powder under UV light excitation (365 nm) (b)

. PL intensity of CsPbBr₃ NCs powder with different size of grind medium under the same test condition

. PL intensity of CsPbBr₃ NCs powder with different ball-to-powder ratio under the same condition

. (a) PL emission spectra of CsPbX₃ NCs powder, the corresponding optical images under normal daylight and UV light (black background) were exhibited inside; (b) Color gamut spectra of perovskite NCs (the inner black line indicating NTSC)

. EDS information of CsPbI₃ NCs powder(a) SEM image with corresponding atomic percentage information; (b) EDS spectrum of CsPbI₃ NCs

. SEM images of CsPbX₃ NCs

. PL spectra of CsPbBr₃ NCs powder with various rotation speed of the planetary mill

. The air stability of CsPbI₃ NCs powder (a) The PL stability exposed in air; (b) X-ray diffraction (XRD) pattern of CsPbI₃ NCs powder; (c) Photographs of the powder samples with time changing under the sunlight (left) and UV light (right)

. The X-Ray diffraction spectra of CsPbX₃ NCs powder with various halogen ratios

. The PL spectrum of CsPbI₃ powder adding amount of 0.2 g of BN

. Analysis of air stability of CsPbI₃ NCs (a) Stability test of CsPbI₃ NCs powder with different BN quantity; (b) SEM image of CsPbI₃ NCs; (c) Energy dispersive spectroscopy (EDS) mapping images of (b)

. Proof-of-concept demonstration of white LED by blending green and red Pe-NCs on a commercial blue LED chip (a) Schematically depicts the packing method of white LED; (b) EL spectra of three typical devices exhibiting (1) green-white, (2) white, and (3) red-white; (c) Photographs of the white LED under different operating voltage

. The stability of white-light LED (a) The luminance stability of white-light LED placed in the air measured at the voltage of 2.7 V; (b) The working stability of the white-light LED after continuous operating for 2 h

Table 1. Comprehensive comparisons for the representative perovskite NCs

Table 2. Comparison of FWHM of CsPbX₃ with typical solution synthesis