Abstract
Perovskite light-emitting diodes (PeLEDs) with an external quantum efficiency exceeding 20% have been achieved in both green and red wavelengths1–5; however, the performance of blue-emitting PeLEDs lags behind6,7. Ultrasmall CsPbBr3 quantum dots are promising candidates with which to realize efficient and stable blue PeLEDs, although it has proven challenging to synthesize a monodispersed population of ultrasmall CsPbBr3 quantum dots, and difficult to retain their solution-phase properties when casting into solid films8. Here we report the direct synthesis-on-substrate of films of suitably coupled, monodispersed, ultrasmall perovskite QDs. We develop ligand structures that enable control over the quantum dots’ size, monodispersity and coupling during film-based synthesis. A head group (the side with higher electrostatic potential) on the ligand provides steric hindrance that suppresses the formation of layered perovskites. The tail (the side with lower electrostatic potential) is modified using halide substitution to increase the surface binding affinity, constraining resulting grains to sizes within the quantum confinement regime. The approach achieves high monodispersity (full-width at half-maximum = 23 nm with emission centred at 478 nm) united with strong coupling. We report as a result blue PeLEDs with an external quantum efficiency of 18% at 480 nm and 10% at 465 nm, to our knowledge the highest reported among perovskite blue LEDs by a factor of 1.5 and 2, respectively6,7.
Original language | English (US) |
---|---|
Pages (from-to) | 679-684 |
Number of pages | 6 |
Journal | Nature |
Volume | 612 |
Issue number | 7941 |
DOIs | |
State | Published - Dec 22 2022 |
Funding
This work is financially supported by National Key Research and Development Program of China (2022YFE0201500). We acknowledge financial support from the National Natural Science Foundation of China (nos 91956130, 62104116, 22121005 and 52072185). Y.J. acknowledges the project funded by the China Postdoctoral Science Foundation (no. 2021M701773). M.Y. acknowledges financial support from Distinguished Young Scholars of Tianjin (no. 19JCJQJC62000). We thank the staff of beamlines BL17B1, BL14B1, BL19U2, BL19U1 and BL01B1 at SSRF for providing the beam time and User Experiment Assist System of SSRF for their help. This work was partly supported by Analysis Platform of New Matter Structure at Nankai University. This work is financially supported by National Key Research and Development Program of China (2022YFE0201500). We acknowledge financial support from the National Natural Science Foundation of China (nos 91956130, 62104116, 22121005 and 52072185). Y.J. acknowledges the project funded by the China Postdoctoral Science Foundation (no. 2021M701773). M.Y. acknowledges financial support from Distinguished Young Scholars of Tianjin (no. 19JCJQJC62000). We thank the staff of beamlines BL17B1, BL14B1, BL19U2, BL19U1 and BL01B1 at SSRF for providing the beam time and User Experiment Assist System of SSRF for their help. This work was partly supported by Analysis Platform of New Matter Structure at Nankai University.
ASJC Scopus subject areas
- General