Bright and Stable Light-Emitting Diodes Based on Perovskite Quantum Dots in Perovskite Matrix

Abstract

Light-emitting diodes (LEDs) based on metal halide perovskite quantum dots (QDs) have achieved impressive external quantum efficiencies; however, the lack of surface protection of QDs, combined with efficiency droop, decreases device operating lifetime at brightnesses of interest. The epitaxial incorporation of QDs within a semiconducting shell provides surface passivation and exciton confinement. Achieving this goal in the case of perovskite QDs remains an unsolved challenge in view of the materials’ chemical instability. Here, we report perovskite QDs that remain stable in a thin layer of precursor solution of perovskite, and we use strained QDs as nucleation centers to drive the homogeneous crystallization of a perovskite matrix. Type-I band alignment ensures that the QDs are charge acceptors and radiative emitters. The new materials show suppressed Auger bi-excition recombination and bright luminescence at high excitation (600 W cm–2), whereas control materials exhibit severe bleaching. Primary red LEDs based on the new materials show an external quantum efficiency of 18%, and these retain high performance to brightnesses exceeding 4700 cd m–2. The new materials enable LEDs having an operating half-life of 2400 h at an initial luminance of 100 cd m–2, representing a 100-fold enhancement relative to the best primary red perovskite LEDs.

Spectral Stable Blue-Light-Emitting Diodes via Asymmetric Organic Diamine Based Dion–Jacobson Perovskites

“…For example, to further increase the phase stability in Br/Cl mixed perovskite films, composition engineering will be a promising strategy to control halide migration and/or phase segregation to achieve highly efficient and stable PeLEDs. 36 , 55 , 56 …”

“…On the other hand, the efficiency and lifetime of our DPDA-perovskite-based PeLED devices still have room to further improve. For example, to further increase the phase stability in Br/Cl mixed perovskite films, composition engineering will be a promising strategy to control halide migration and/or phase segregation to achieve highly efficient and stable PeLEDs. ,, …”

“…36,55,56 ■ CONCLUSION Phase stable blue PeLEDs are realized by incorporating asymmetric divalent organic cations. The DPDA cations lead to the formation of DJ phase perovskites.…”

Stable and Efficient Red Perovskite Light-Emitting Diodes Based on Ca 2+ -Doped CsPbI 3 Nanocrystals

“…Based on the HRTEM images, the cubic NCs become truncated cubic NCs (Figure S1a-d ). Therefore, (110) crystal planes are more exposed and enhance the peak at 20° [ 47 , 48 ]. Furthermore, the morphology and size characterization for Ca 2+ -doped CsPbI 3 NCs were studied by TEM.…”

Strategies of Improving CsPbX3 Perovskite Quantum Dots Optical Performance

“…Yi-Xin also found that the CsPbBr 3 halide perovskite photocatalyst significantly affected the CO 2 reduction performance, achieving a higher reaction rate and long-term stability. Liu et al (2021) used strained perovskite QDs as nucleation centers to make the film crystallization more uniform and stable. This method reduced gradient crystallization and suppressed halide segregation, leading to the efficient transport of charge carriers, the red CsPbI 3 QDs films based LED showed external quantum efficiency (EQE) of 18% and remained half of the initial luminance even after 2,400 h working.…”