Affiliation:
1. Key Laboratory of Materials for High‐Power Laser Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai 201800 P. R. China
2. Australian Institute for Bioengineering and Nanotechnology The University of Queensland St Lucia Brisbane Queensland 4072 Australia
3. Faculty of Materials Science and Engineering/Institute of Technology for Carbon Neutrality Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen 518055 P. R. China
4. Key Laboratory for Micro‐Nano Physics and Technology of Hunan Province State Key Laboratory of Chemo/Biosensing and Chemometrics Hunan Institute of Optoelectronic Integration College of Materials Science and Engineering Hunan University Changsha 410082 P. R. China
5. Department of Applied Physics The Hong Kong Polytechnic University Kowloon Hong Kong 999077 P. R. China
Abstract
AbstractMetal halide perovskite nanocrystals (PNCs) hold great promise for light‐emitting diodes (LEDs) due to their high photoluminescence quantum yields (PLQY), tunable colors, and low‐cost solution processability. However, their electroluminescence efficiencies are currently limited by the small size of the PNCs and the weak binding between ligands and PNCs. The small size makes PNCs sensitive to environmental factors due to their large specific surface area, leading to a loss of PLQY during post‐treatment. Additionally, the weak binding between ligands and PNCs causes the ligands to detach during post‐treatment, further reducing PLQY. To address these challenges, an in situ ligand‐capped synthesis method is introduced for PNCs, replacing the aliphatic solvent octadecene (ODE) with trioctylphosphine (TOP). The presence of TOP increases the concentration of monomers, accelerating nucleation and crystal growth, enabling the production of cubic PNCs ranging from 8 nm to over 28 nm. Moreover, TOP acts as a ligand to resurface PNCs, enhancing their stability and maintaining high PLQY after post‐treatment. As a result, by utilizing these larger PNCs, a high maximum external quantum efficiency (EQE) of 21.23% in LEDs is achieved. This method provides a significant advancement in the development of high‐performance PNC‐based LEDs.
Funder
Basic and Applied Basic Research Foundation of Guangdong Province
Science and Technology Commission of Shanghai Municipality
National Natural Science Foundation of China