Molecular design, synthesis, properties, and applications of organic triplet emitters exhibiting blue, green, red and white room-temperature phosphorescence

At room temperature, many organic compounds can emit light not only from singlet excited states but also from triplet excited states. This phenomenon is known as room-temperature phosphorescence (RTP). RTP has numerous potential applications in various areas, including industry, medicine, and daily life. RTP materials can be used in white light-emitting, memorising, sensing, bioimaging, semiconducting, 3D printing, microfluidic visualisation, quantum computing, X-ray detection, etc. They have advantages over fluorescent and metal-based phosphorescent materials. They are characterized by different emission spectra, longer lifetimes, and higher environmental sensitivity. However, challenges related to the tuning of emission colours, realization of dual emission, and meeting application-specific requirements still need to be overcome. Various molecular design strategies and synthetic approaches have been developed to overcome these challenges and to develop efficient RTP materials. This review article discusses recent advances in the synthesis and properties of RTP materials, focusing on emission colours and applications. Theoretical and experimental approaches for the development of organic room temperature phosphorescence compounds exhibiting blue, green, red, and white emissions for many potential applications are analysed and classified.