One-Pot Synthesis of High-Quality CsPbI₃ Nanoplatelets with Orange-Red Light Emission

CsPbI3 nanoplatelets (NPLs) are considered potential candidates for orange-red light-emitting materials due to their high exciton binding energy and narrow full width at half maximum (FWHM). However, the relatively low formation energy of CsPbI3 NPLs leads to rapid growth rates, posing a challenge for the controlled synthesis of high-quality CsPbI3 NPLs. Herein, we report the synthesis of high-quality CsPbI3 NPLs emitting orange-red light using a one-pot method under mild reaction conditions. The protonation of oleylamine (OAm) by introducing HI and the strong interaction between the octadecylphosphonic acid (ODPA) ligand and Pb2+ facilitate the anisotropic growth of CsPbI3 NPLs and enable precise control over the numbers of NPL layers, achieving the desired orange-red light emission. The resulting CsPbI3 NPLs exhibited a high photoluminescence quantum yield (PLQY) of up to 90%, a narrow FWHM of only 25 nm, and excellent stability at room temperature, under ultraviolet–visible light and in aqueous environments. The comprehensive study of the formation process of CsPbI3 NPLs enriches our understanding of the growth mechanism and provides a synthetic route for producing high-quality CsPbI3 NPLs.