Few-Nanometer-Sized α-CsPbI3 Quantum Dots Enabled by Strontium Substitution and Iodide Passivation for Efficient Red-Light Emitting Diodes

• DOI: 10.1021/jacs.8b11447
• Publication Date: 2019-01-08T22:09:00Z
• Authors: Ji-Song Yao; Jing Ge; Kun-Hua Wang; Guozhen Zhang; Bai-Sheng Zhu; Chen Chen; Qun Zhang; Yi Luo; Shu-Hong Yu; Hong-Bin Yao
• Keywords: Passivation; Nanometre; Substitution (logic)

Cubic phase CsPbI3 quantum dots (α-CsPbI3 QDs) as a newly emerging type of semiconducting QDs hold tremendous promise for fundamental research and optoelectronic device applications. However, stable sub-5 nm-sized α-CsPbI3 have rarely been demonstrated so far due to their highly labile ionic structure low stability. Here, we report novel strontium-substitution along with iodide passivation strategy stabilize the cubic CsPbI3, achieving facile synthesis series controllable sizes down nm. We demonstrate that incorporation strontium ions can significantly increase formation energies hence reduce distortion at few-nanometer size. The size ranging from 15 nm as-prepared allowed us investigate unique size-dependent optical properties. Strikingly, few-nanometer-sized turned out retain high photoluminescence close packing in solid state thin films, fabricated red light emitting diodes exhibited brightness (1250 cd m–2 9.2 V) good operational stability (L50 > 2 h driven by 6 V). developed cation-substitution will provide an alternative method prepare uniform finely size-controlled colloidal lead halide perovskite various