Recent advances of room temperature phosphorescence and long persistent luminescence by doping system of purely organic molecules

Recently, the research of organic room-temperature phosphorescent materials (ORTP) and organic long persistent luminescence (OLPL) has become a hot topic in the fields of chemistry and material science. To date, there are many reports on the realization of high-efficiency ORTP and OLPL by doping system of organic small molecules, which have attracted widespread attention due to their unique luminescence performance. However, given the lack of clear molecular design principles and comprehension in elucidating the complex doping mechanisms, the development of ORTP and OLPL by doping system is strongly limited, as well as further practical application. A variety of activation strategies including rigidification, energy transfer, charge transfer (CT) intermediated state and cluster have been developed in the reported doping system. Moreover, OLPL materials were also developed with impressive luminescent lifetime. This mini-review summarizes the recent research progress of ORTP and OLPL by doping system of organic small molecules. The reported doping systems of the organic molecules are mainly categoried according to the different luminescent mechanisms, combined with the discussion on the relationship between molecular structure and luminescent performance. This would be helpful to understand luminescent characteristics deeply and further develop efficient ORTP and OLPL doping systems. Last but not the least, this review presents the current challenges and prospects of future development in this field.