Benzophenone-containing phosphors with an unprecedented long lifetime of 1.8 s under ambient conditions.

It is well-known that benzophenone has a short phosphorescence lifetime of around 1 ms even at 77 K. Here we report a benzophenone-containing emitter with an unprecedented long phosphorescence lifetime of 1.8 s under ambient conditions, which can be attributed to its T 1 state of localized excitation nature as revealed by detailed studies.