In recent years, lead-free double perovskites (DPs) have attracted great attention in the field of optoelectronics with their strengths, such as low toxicity, excellent stability and solution processability. However, the shortcomings of their quantum dots such as the high defect density and poor charge mobility have made the external quantum efficiency (EQE) extremely low in electroluminescent (EL) devices.
To address the concerns, Professor Chen Daqin’s research team employed Tb (terbium) doping and a host-guest strategy, achieving an improvement in CE (current efficiency) of EL devices from 0.110 cd A-1 to 0.634 cd A-1, EQE from 0.08% to 0.76%, and luminance from 158 cd m-2 to 2793 cd m-2. The improvement is attributed to the inhibited formation of metallic Ag nanoparticles, the confined spatial distribution of STEs (self-trapped excitons), and the reduction in local site symmetry by Tb doping, and the host-guest strategy improved film morphology, reduced defect density and increased carrier mobility. Besides, pure white electroluminance with ideal color coordinates of (0.328, 0.329) and a record-breaking optoelectronic performance was achieved by introducing additional green carbon dots in light-emitting diodes (LEDs) to fill the deficient green component.
The research findings, titled “Highly bright and stable lead-free double perovskite white light-emitting diodes,” have been published in the academic journal Advanced Materials. The first affiliation of the paper is FNU, with Jin Shilin, a doctoral candidate of FNU, as the first author and Professor Chen Daqin as the corresponding author. The work was supported by the National Key Research and Development Program of China, the National Natural Science Foundation of China, the Natural Science Foundation of Fujian Province, and so on.
Official website link: https://doi.org/10.1002/adma.202308487
(Translated by Xiao Zhiying/ Reviewed by Xie Xiujuan)