Composition-tailored ZnMgO nanoparticles for electron transport layers of highly efficient and bright InP-based quantum dot light emitting diodes

Abstract

The energy diagram of InP-based QLEDs and EQE enhancement by tailored-ZnMgO ETLs.

Progress of display performances: AR, VR, QLED, and OLED

“…This work also reported the high brightness of ∼ 100,000 cd/m 2 as well as enhanced operational lifetime. Bright and efficient green-emitting InP QLEDs with narrow spectral bandwidths (FWHM < 40 nm) were also reported by introducing a hole-suppressing interlayer with a top emission structure [59], and by adopting the composition-tailored ZnMgO nanoparticles as the ETL [66]. These results are brightening the prospects of using Cd-free QDs for the practical QLEDs.…”

Blue quantum dot-based electroluminescent light-emitting diodes

“…Among the non-Cd QDs, InP QDs have been highlighted as the most promising alternatives to CdSe QDs because of their increasingly enhanced PL characteristics in terms of PL line width and PL QY, mainly enabled by an elaborate control of InP core size distribution and rational multi-shell-based heterostructural engineering. [103][104][105] Following years of hard work on the optimization of emitting materials, device architecture, and deep understanding of the operational mechanism, the Z EQE of red and green InP-based QD-LEDs has exceeded 12% and 13%, respectively; 25,26 however, their blue-emitting counterpart has been challenging because of a relatively small bulk bandgap (1.35 eV at room temperature) of InP QDs. 106 In 2017, Shen et al synthesized high PL QY (up to 76%) InP/ZnS small-core/ thick-shell tetrahedral-shaped QDs for blue QD-LEDs for the first time.…”

“…24 In addition, for InP-based QDs, the peak Z EQE of red and green QD-LEDs also exceeded 12% and 13%, respectively, through the optimization of the composition gradient in QD shells and the doping of the ZnO electron transport layer (ETL). 25,26 Nevertheless, heavy-metal-free blue QD-LEDs have been rarely reported.…”

Synthesis of Blue-Emissive InP/GaP/ZnS Quantum Dots via Controlling the Reaction Kinetics of Shell Growth and Length of Capping Ligands

“…The QLEDs with a conventional device architecture were fabricated by all-solution processing, as shown in Figure 6a and their performance was investigated. The blended hole transport layer (HTL) of poly-TPD and PVK was employed owing to the advantages of the fast mobility of poly-TPD and the high energy level of PVK, which is more suitable for InP-based QLEDs, as reported in our previous studies [43]. The device exhibited an electroluminescence (EL) peak emission at 491 nm with a FWHM of 66 nm (at 7 V), which was slightly red-shifted by 6 nm compared with the PL spectra (485 nm) owing to the well-known quantum confinement Stark effect (Figure 6b) [44].…”