Luo Jiajun, Hu Manchen, Niu Guangda, Tang Jiang
Sargent Joint Research Center, Wuhan National Laboratory for Optoelectronics (WNLO) and School of Optical and Electronic Information , Huazhong University of Science and Technology , Wuhan 430074 , China.
ACS Appl Mater Interfaces. 2019 Sep 4;11(35):31575-31584. doi: 10.1021/acsami.9b08407. Epub 2019 Aug 26.
Lead halide perovskites have attracted tremendous research interests in the light-emitting field because of their high defect tolerance, solution processability, tunable spectrum, and efficient emission. In terms of luminescence types, both the narrowband emission derived from free-exciton (FE) and broadband white light emission from self-trapped exciton (STE) show great advantages in light-emitting applications. Despite the fascinating characteristics, their commercialization still suffers from the presence of toxic lead (Pb) and unsatisfactory stability. In this spotlight, we mainly focus on the lead-free candidates as phosphors for possible light-emitting applications. Thanks to the chemical diversity of metal halide perovskites and perovskite variants, many excellent lead-free light-emitting materials have recently been synthesized and characterized. We first classify these materials into three types according to material structures, including (1) double perovskites AB(I)B(III)X, (2) vacancy ordered perovskites AB(IV)X, (3) miscellaneous perovskite variants or halide semiconductors, which refer to halides without clear relation to the perovskite structure. We then highlight the importance of electronic dimensionality, defect passivation, and impurity doping in developing highly efficient perovskite-based emitters. We also discuss their applications in white light-emitting diodes (W-LED). Further challenges toward practical applications and potential applications are also included in a section on outlook and future challenges.
卤化铅钙钛矿因其高缺陷容忍度、溶液可加工性、可调谐光谱和高效发射等特性，在发光领域引起了巨大的研究兴趣。就发光类型而言，源自自由激子（FE）的窄带发射和自陷激子（STE）的宽带白光发射在发光应用中均显示出巨大优势。尽管具有这些迷人的特性，但其商业化仍受限于有毒铅（Pb）的存在以及稳定性不尽人意。在本专题文章中，我们主要聚焦于作为可能的发光应用荧光粉的无铅候选材料。得益于金属卤化物钙钛矿和钙钛矿变体的化学多样性，最近已合成并表征了许多优异的无铅发光材料。我们首先根据材料结构将这些材料分为三类，包括（1）双钙钛矿AB(I)B(III)X，（2）空位有序钙钛矿AB(IV)X，（3）杂项钙钛矿变体或卤化物半导体，后者指与钙钛矿结构无明确关系的卤化物。然后，我们强调了电子维度、缺陷钝化和杂质掺杂在开发高效钙钛矿基发光体中的重要性。我们还讨论了它们在白光发光二极管（W-LED）中的应用。展望与未来挑战部分还包括了实际应用和潜在应用面临的进一步挑战。
