Pure Cs4PbBr6: Highly Luminescent Zero-Dimensional Perovskite Solids

• Published in: ACS energy letters Vol. 1; no. 4; pp. 840 - 845
• Main Authors: Saidaminov, Makhsud I, Almutlaq, Jawaher, Sarmah, Smritakshi, Dursun, Ibrahim, Zhumekenov, Ayan A, Begum, Raihana, Pan, Jun, Cho, Namchul, Mohammed, Omar F, Bakr, Osman M
• Format: Journal Article
• Language: English
• Published: American Chemical Society 14.10.2016
• ISSN: 2380-8195; 2380-8195
• DOI: 10.1021/acsenergylett.6b00396

So-called zero-dimensional perovskites, such as Cs4PbBr6, promise outstanding emissive properties. However, Cs4PbBr6 is mostly prepared by melting of precursors that usually leads to a coformation of undesired phases. Here, we report a simple low-temperature solution-processed synthesis of pure Cs4PbBr6 with remarkable emission properties. We found that pure Cs4PbBr6 in solid form exhibits a 45% photoluminescence quantum yield (PLQY), in contrast to its three-dimensional counterpart, CsPbBr3, which exhibits more than 2 orders of magnitude lower PLQY. Such a PLQY of Cs4PbBr6 is significantly higher than that of other solid forms of lower-dimensional metal halide perovskite derivatives and perovskite nanocrystals. We attribute this dramatic increase in PL to the high exciton binding energy, which we estimate to be ∼353 meV, likely induced by the unique Bergerhoff–Schmitz–Dumont-type crystal structure of Cs4PbBr6, in which metal-halide-comprised octahedra are spatially confined. Our findings bring this class of perovskite derivatives to the forefront of color-converting and light-emitting applications.