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 highdefinition display.