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

CsPbI 3 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 CsPbI 3 NPLs leads to rapid growth rates, posing a challenge for the controlled synthesis of high-quality CsPbI 3 NPLs. Herein, we report the synthesis of high-quality CsPbI 3 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 Pb 2+ facilitate the anisotropic growth of CsPbI 3 NPLs and enable precise control over the numbers of NPL layers, achieving the desired orange-red light emission. The resulting CsPbI 3 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 CsPbI 3 NPLs enriches our understanding of the growth mechanism and provides a synthetic route for producing high-quality CsPbI 3 NPLs.