2020 Volume 59 Issue 3 Pages 316-324
Long-persistent luminescent (LPL) materials can absorb photon energy and emit light over a long period of time. While all existing LPL materials are composed of inorganic materials, we demonstrated an organic LPL (OLPL) system composed only of organic materials. The OLPL system consists of an electron donor material and an acceptor material that stores energy in a charge-separated state rather than an excited state. The OLPL systems do not require rare metals, can be fabricated from a solution, and has characteristics that are difficult to achieve with conventional inorganic materials such as flexibility and transparency. The emission color of OLPL system is controlled by the energy gap between the HOMO level of the donor and the LUMO level of the acceptor. In addition, the triplet excited states of each materials affect the LPL process. The extra fluorescent dopants enable to control the emission color and extend the emission duration.
