The main issue in developing a quantum dot light-emitting diode (QLED) display lies in successfully replacing heavy metals with environmentally benign materials while maintaining high-quality device performance. Nonradiative Auger recombination is one of the major limiting factors of QLED performance and should ideally be suppressed. This study scrutinizes the effects of the shell structure and composition on photoluminescence (PL) properties of InP/ZnSeS/ZnS quantum dots (QDs) through ensemble and single-dot spectroscopic analyses. Employing gradient shells is discovered to suppress Auger recombination to a high degree, allowing charged QDs to be luminescent comparatively with neutral QDs. The "lifetime blinking"phenomenon is observed as evidence of suppressed Auger recombination. Furthermore, single-QD measurements reveal that gradient shells in QDs reduce spectral diffusion and elevate the energy barrier for charge trapping. Shell composition dependency in the gradience effect is observed. An increase in the ZnS composition (ZnS >50%) in the gradient shell introduces lattice mismatch between the core and the shell and therefore rather reverses the effect and reduces the QD performance.
Bibliographical noteFunding Information:
The work at Yonsei University was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT) (No. 2021R1A2C300630811). The work at Hongik University was financially supported by the Technology Innovation Program (20010737) funded by the Ministry of Trade, Industry & Energy (MOTIE, Korea).
© 2022 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Materials Science(all)