| 초록 |
Inter- and intra molecular excited charge transfer complexes (exciplex and TADF molecules) formed between donor and acceptor materials (groups) are attracting a lot of attention in OLEDs as a third generation light emitting materials and host materials to harvest triplet excitons. Exciplexes and TADF molecules have been utilized as hosts for phosphorescent and TADF dyes to realize low driving voltage, excellent exciton formation efficiency, and low efficiency roll-offs. EQEs of OLEDs using TADF molecules as the emitters reach about 40% in the same level of phosphorescent OLEDs. EQEs of exciplex OLEDs has been steadily improved. In addition to that, exciplexes and TADF molecules have been used as triples harvesting sensitizers for fluorescent dyes to realized high efficiency on the one hand by harvesting triplet excitons and long lifetime by utilizing short exciton lifetime of fluorescent molecules on the other hand. In this presentation, we will firstly discuss on the high efficiency OLEDs employing exciplexes and/or TADF molecules reported in my lab. Then the relationship between molecular conformation (configuration) and exciton formation & excited state dynamics such as RISC, transient decay, emission spectra, and diffusion will be discussed. |
