Universal surface tailoring of perovskite nanocrystals via organic pseudohalide ligands applicable to green and blue light-emitting diodes

• Published in: Journal of materials chemistry. C, Materials for optical and electronic devices Materials for optical and electronic devices, 2022-12, Vol.10 (48), p.18226-18233
• Main Authors: Ko, Jaewan, Je, Hyeondoo, Kim, Kitae, Eom, Taejun, Joung, Joonyoung F., Park, Sungnam, Bang, Joona, Choi, Dong Hoon
• Format: Article
• Language: English
• Subjects: Ligands; Light emitting diodes; Nanocrystals; Optical properties; Passivity; Perovskites; Photoluminescence; Surface defects; Surface stability
• ISSN: 2050-7526; 2050-7534
• DOI: 10.1039/D2TC04194D

Proper management of surface defects in perovskite nanocrystals (PeNCs) has resulted in near-unity photoluminescence quantum yield and the development of high-performance light-emitting diodes (LEDs). However, most PeNCs still suffer from incomplete surface passivation, which results in non-ideal efficiencies. Herein, we devise a simple surface tailoring of CsPbBr 3 NCs with organic pseudohalide ligands, didodecyldimethylammonium tetrafluoroborate (DDA-BF 4 ). Results suggest that the DDA cation and BF 4 anion simultaneously coordinated on the CsPbBr 3 NC surfaces, thereby dramatically improving optical properties and colloidal stability. With this passivation, surface-tailored CsPbBr 3 NCs were applied to green LEDs, which showed significantly higher external quantum efficiencies than LEDs with untreated PeNCs and stable electroluminescence (EL) at a wavelength of 516 nm. Also, when this method was applied to sky-blue LED based on CsPbBr 3− x Cl x NCs (EL at 484 nm), similar improvement in device performance was observed. We believe that organic pseudohalide treatment provides a universal methodology that can be applicable to green and blue PeNC-based LEDs, providing a promising platform for future displays and lighting technologies.