Warm White Light from a Single LED Material

Phosphor-coated LEDs have become a low-energy alternative to incandescent lighting. The blue-tinged light they give off, however, is not ideal for indoor living spaces, where consumers prefer warmer tones. Now, an international research team has discovered a material that the researchers believe could replace the LEDs’ phosphor coating and produce a warm white light while consuming even less energy. The material is a lead-free halide double perovskite. Metal halide perovskites are used in optoelectronic devices because they are tolerant to defects and are inexpensive to process. They also exhibit tunable emission across the visible spectrum. But many of those that perform best contain lead, an environmentally hazardous substance, and can be unstable.