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.