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

Abstract 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.