Getting that organic glow

Phosphorescent materials, which continue to glow even after the light that put them into an excited state has been removed, have applications in electronics, optics, and biology. But achieving phosphorescence at room temperature and in the presence of oxygen can be tough because the excited state of such molecules is sensitive to these conditions. To date, most compounds that exhibit room-temperature phosphorescence contain metals, making them more costly and potentially toxic. Chemists in China now report a series of five organic molecules that efficiently and persistently phosphoresce in a range of colors in air and at room temperature (Chem 2016, DOI: 10.1016/​j.chempr.2016.08.010). The team, led by Ben Zhong Tang of Hong Kong University of Science & Technology and Qian Peng of the Institute of Chemistry, Chinese Academy of Sciences, designed the aromatic carbonyl compounds so that their excited states have a tunable configuration that promotes phosphorescence. The most promising compound, 1-(dibenzo[b,d]furan-2-yl)phenylmethanone, or BDBF, has a phosphorescence lifetime of 230 milliseconds and an efficiency of 34.5%. The researchers hope the design guidelines they developed will lead to even better organic phosphors.