Warm white light emission

Nature, 563, 541–545 (2018)

Materials with efficient and stable white light emission are indispensable for solid-state lighting and display applications. It is still a great challenge to achieve broadband emission covering the entire visible wavelength range by using a single material up to date. To this end, it is urgent to explore new environment-friendly single materials with high efficient and stable white light emission for commercial lighting applications to reduce the cost and complexity of devices.

Recently, researchers from Huazhong University of Science and Technology and The University of Toledo demonstrated the high efficient and stable warm white light emission in lead-free all-inorganic double perovskite Cs₂AgInC_l6. The white light emission is believed to be from the self-trapped excitons due to the Jahn–Teller distortion of the AgCl₆ octahedron in the excited states induced by the strong electron−phonon coupling. Impressively, by intentionally incorporating the Na element to form alloyed Cs₂(Ag_0.60Na_0.40)InCl₆ with the trace amount of Bi doping, the photoluminescence quantum efficiency can achieve as high as 86 ± 5% with an excellent stability over 1000 hours in air under continuous heating at 150 °C. Those studies would shed light on exploring new lead-free perovskite materials for high efficiency white light devices and stimulate more research on single-emitter-based white-light-emitting phosphors and diodes.

Dehui Li (Huazhong University of Science and Technology, Wuhan, China)

doi: 10.1088/1674-4926/40/2/020202