Cerium-Sensitized Highly Emissive 0D Cesium Cerium Terbium Chloride Alloy Nanocrystals for White Light Emission

Recently, lanthanide-based 0D metal halides have garnered considerable attention owing to their applications in light–emitting diodes (LEDs), X-ray imaging, and photodetectors. Among these materials, 0D Cs₃TbCl₆ (CTC) nanocrystals (NCs) have demonstrated promising performance in X-ray imaging and light-emitting diodes. However, a considerable drawback of CTC NCs is their limited absorption coefficient in the UV-A region (315–380 nm). To address this limitation and enhance the absorption coefficient in the UV-A region, Ce³⁺ is incorporated into CTC NCs—advantageous owing to the high absorption coefficient of Ce³⁺ in the UV-A region, attributed to—4f-5d orbital coupling. In addition, Ce³⁺ ions sensitize the luminescence of CTC NCs and enhance the photoluminescence quantum yield from 75% to 87%. Energy transfer from Ce³⁺ to Tb³⁺ is investigated at different dopant ratios. Furthermore, Cs₃CeTbCl₆ (CCTC) NCs have been utilized in white LED devices. Understanding such competitive energy transfer in lanthanide-based perovskite-inspired metal halides will facilitate the development of novel luminescent metal halides for lighting applications.