Room temperature synthesis of low-dimensional rubidium copper halide colloidal nanocrystals with near unity photoluminescence quantum yield

• Main Authors: Vashishtha, Parth, Hooper, Thomas James Nelson, Fang, Yanan, Deviana, Kathleen, Giovanni, David, Klein, Maciej, Sum, Tze Chien, Mhaisalkar, Subodh Gautam, Mathews, Nripan, White, Tim
• Other Authors: School of Materials Science and Engineering
• Format: Article
• Language: English
• Published: 2020
• Subjects: Engineering::Materials; Nanocrystals; Photoluminescence Quantum Yield
• Online Access: https://hdl.handle.net/10356/145108
• Institution: Nanyang Technological University

Metal lead halide perovskite nanocrystals have emerged as promising candidates for optoelectronic applications. However, the inclusion of toxic lead is a major concern for the commercial viability of these materials. Herein, we introduce a new family of non-toxic reduced dimension Rb2CuX3 (X= Br, Cl) colloidal nanocrystals with one-dimensional crystal structure consisting [CuX4]3- ribbons isolated by Rb+ cations. These nanocrystals were synthesised using a room-temperature method under ambient conditions, which makes them cost effective and scalable. Phase purity quantification was confirmed by Rietveld refinement of powder x-ray diffraction and corroborated by 87Rb MAS NMR technique. Both samples also exhibited high thermal stability up to 500°C, which is essential for optoelectronic applications. Rb2CuBr3 and Rb2CuCl3 displays PL emission peaks at 387 nm and 400 nm with high PLQYs of ~100% and ~49%, respectively. Lastly, the first colloidal synthesis of quantum-confined rubidium copper halide-based nanocrystals opens up a new avenue to exploit their optical properties in lighting technology as well as water sterilisation and air purification.