Efficient White Electroluminescence from Cu-based Perovskite Achieved by High Hole Injection Core/Shell Structures

Area of Science:

• Materials Science
• Solid State Physics
• Optoelectronics

Background:

• Copper-based halide perovskites offer eco-friendly, bright broadband emission suitable for white light applications.
• Limited hole injection in these materials hinders the efficiency of white perovskite light-emitting diodes (W-PeLEDs).

Purpose of the Study:

• To overcome the hole injection limitations in copper-based perovskites for improved W-PeLED performance.
• To develop efficient, lead-free white light-emitting materials.

Main Methods:

• Synthesized lattice-matched core/shell nanocrystals (NCs) using Cs₃Cu₂I₅ core and p-type cuprous sulfide (Cu₂S) shell.
• Controlled sulfur precursor reactivity to achieve desired core/shell nanostructures.
• Fabricated W-PeLEDs using the engineered Cs₃Cu₂I₅/Cu₂S NCs.

Main Results:

• The Cs₃Cu₂I₅/Cu₂S NCs exhibited significantly enhanced hole mobility compared to pristine Cs₃Cu₂I₅ NCs.
• Photoluminescence quantum yield increased from 26.8% to 70.6% after Cu₂S capping.
• Achieved an external quantum efficiency of 3.45% and a color-rendering index (CRI) of 91 in W-PeLEDs.

Conclusions:

• Lattice-connected Cu₂S capping effectively enhances hole mobility and luminescence in Cs₃Cu₂I₅-based materials.
• The developed CsCu₂I₃/Cs₃Cu₂I₅/Cu₂S structure represents a significant advancement in lead-free W-PeLED technology.
• Provides effective strategies for designing high-performance broadband electroluminescent materials and PeLED devices.