An international research team led by the University of Houston researchers have tackled a lingering question about how a two-dimensional perovskite crystal composed of cesium, lead and bromine emits a strong green light. Crystals that produce light on the green spectrum are desirable because green light, while valuable in itself, can also be relatively easily converted to other forms that emit blue or red light, making it especially important for optical applications ranging from light-emitting devices to sensitive diagnostic tools.
There was, however, confusion as to how the crystal, CsPB2Br5, produced the green photoluminescence. Several theories emerged, without a definitive answer. Now, the researcher team from the United States, Mexico and China, led by the University of Houston, have reported that they have used sophisticated optical and high-pressure diamond anvil cell techniques to determine not only the mechanism for the light emission but also how to replicate it.