Study On The Construction And Properties Of Exciplex Organic Photoelectric Materials

In the last three decades,organic light-emitting devices(OLEDs)have attracted enormous attention in lighting applications and for usage in flat-panel displays.In addition to traditional OLEDs,a new class of efficient OLEDs was recently demonstrated by Goushi and coworkers by forming an intermolecular CT excited state(i.e.exciplex)between electron-donating and electron-accepting molecules.Hence,fluorescent OLEDs based on exciplex emitters theoretically have 100%internal quantum efficiencies,which corresponds to maximum EQEs of 20%.However,there are still a number of challenges and questions to suppress its development.In this paper,the basic method of constructing exciplex is explored by theoretical calculation,and a new exciplex system is prepared.(1)Theoretical calculation of intramolecular exciplex.Using the intramolecular exciplex complex molecules reported in the literature.Based on the principle of the control variables,three intramolecular exciplex molecules and one contrast molecule were designed.Some conclusions are drawn through theoretical calculations.Not all exciplex complex molecules are TADF molecules;the triplet energy level of the exciplex complex molecules is less than the triplet energy level(E_T)of each monomer to prevent energy leakage.This is more conducive to the formation of exciplex;at the same time,the most important finding is that there is more charge transfer between the donor and the acceptor,and there is a weak interaction between the D and A,which is beneficial for the exciplex.of.form.These findings have a guiding role in the design of subsequent exciplex systems.(2)Theoretical calculation of intermolecular exciplex.Based on PO-T2T,three intermolecular exciplex were reported in the literature,namely MAC:PO-T2T,mCP:PO-T2T,TCTA:PO-T2T,and DPhPz,rDPhPz and PhCz were also selected as donors.According to the calculation method of the intramolecular exciplex,a conclusion similar to the intramolecular exciplex is obtained.(3)Experimental study of exciplex.According to the above-mentioned intermolecular exciplex system,the emission spectra and lifetime tests of the monomers and complexes were carried out on six systems to further investigate and confirm the formation of intermolecular exciplex complexes.