Photoluminescent Properties of Copper Halide Semiconductors

Copper halide semiconductors have attracted intense interest as lead-free, low-dimensional materials exhibiting strong photoluminescence across the visible spectrum. Their emission arises predominantly from self-trapped excitons, in which lattice distortions localise excited electron–hole pairs. Variations in composition (for example, CsCu₂I₃ versus Cs₃Cu₂Br₅), dimensionality (zero-, one- or higher-dimensional networks) and surface chemistry enable fine tuning of emission colour, bandwidth and stability. Advances in ligand engineering, defect passivation and crystal growth have pushed photoluminescence quantum yields (PLQYs) above 90 % in selected systems, while novel synthetic routes in aqueous or ambient conditions support scalable, eco-friendly production. These materials are reshaping approaches to white-light generation, ultraviolet detection and visible-light communication by delivering broad emission profiles, high external quantum efficiency (EQE) and extended operational lifetimes. Their tunable electronic structure, combined with compatibility with solution processing, underscores a growing portfolio of applications in solid-state lighting, displays, sensing and scintillation. Ongoing work seeks to deepen understanding of electron–phonon coupling, trap dynamics and exciton binding to further optimise brightness, chromaticity and thermal resilience.

Research from Nature Portfolio

Solution-processed warm-white light-emitting diodes based on cesium copper halides have demonstrated that simple organic additives can simultaneously reduce nonradiative trap states and enhance charge injection. By incorporating a surface-active polyethylene glycol sorbitan monooleate into precursor films, researchers achieved an external quantum efficiency of over 3 % and peak luminance exceeding 1500 cd m⁻² at low drive voltages. Trap-state suppression increased photoluminescence quantum yield, while modified surface potential improved hole transport, resulting in bright, stable electroluminescence from lead-free copper halides. The work establishes a blueprint for additive-guided optimisation of broad-spectrum emission in environmentally benign metal-halide devices.

Photoluminescent Properties of Copper Halide Semiconductors publication trend

The graph below shows the total number of articles in photoluminescent properties of copper halide semiconductors across all publications each year (not limited to Nature Index journals).

Technical terms

Photoluminescence quantum yield (PLQY): Ratio of the number of photons emitted to the number of photons absorbed under optical excitation.

Self-trapped exciton (STE): An exciton localised by lattice distortion, leading to broad, red-shifted emission bands.

External quantum efficiency (EQE): Fraction of injected charge carriers that recombine radiatively to emit photons in an electroluminescent device.

Full width at half maximum (FWHM): Spectral width of an emission peak measured at half its maximum intensity.

References

1. Direct synthesis of high quantum yield lead‐free CsCu2I3 powder in water and its application in yellow LED. Exploration (2024).
2. Efficient and bright broadband electroluminescence based on environment-friendly metal halide nanoclusters. Light: Science & Applications (2024).
3. Efficient and bright warm-white electroluminescence from lead-free metal halides. Nature Communications (2021).
4. Pressure‐assisted cooling to grow ultra‐stable Cs3Cu2l5 and CsCu2l3 single crystals for solid‐state lighting and visible light communication. EcoMat (2022).