Stable and Efficient Red-Emitting Perovskite Cross-Shaped Nanoplates

The stable cross-shaped CsPbI₃ nanoplates (NPs) with red emission were achieved by chemical synthesis with the assistance of YCl₃. Y³⁺ replacing Pb²⁺ results in the anisotropic growth of the CsPbI₃ nanocrystal to form NPs. Four corners of the NPs dissolved, thus forming the cross-shaped NPs. The emission of NPs was shifted from near-infrared (690 nm) to red emission (640 nm) as the dopant amount of Y³⁺ increased. Y³⁺ widens the width of the bandgap, which is also proved by first-principles calculations. In addition, the Cl^- passivated the surface defects of the NPs, suppressing the nonradiative recombination. The NPs showed remarkable high photoluminescence quantum yields (PLQY) of 96%. PLQY is even more than 60% when NPs have been stored in a glovebox for more than 90 days. The NPs with adjustable wavelength and enhanced stability have a huge application potential in the field of a high-definition display.