Third-generation OLEDs based on thermally activated delayed fluorescence (TADF), unlike phosphorescent OLEDs, do not require expensive and environmentally unfriendly heavy metal complexes. In TADF-based OLEDs, high efficiency is achieved through reverse intercommunic conversion from the excited triplet state to the excited singlet state. Such conversion is possible only when the difference between the energies of the siglet and triplet energy level is very small. As a result of this conversion, TADF-based OLEDs operate on both singlet and triplet excitons and have a theoretical internal quantum efficiency of 100%. Sufficiently high OLED efficiency can also be achieved with another type of delayed fluorescence – triplet anihilation. The aim of this project is to study the photophysical and electroluminescent properties of novel compounds with delayed fluorescence (thematically activated delayed fluorescence or triplet anihilation). The photophysical properties (photoluminescence spectra, photoluminescence quenching dynamics, photoluminescence quantum yields) and the charge transfer properties of their layers will be investigated for 3-5 dilute solutions of new compounds and solid samples. The most promising compounds will be tested as emitters in OLED structures. The electroluminescent characteristics of the formed devices will be determined and analyzed.
Project funding:
Project is funded by EU Structural Funds according to the 2014–2020 Operational Programme for the European Union Funds’ Investments priority “Development of scientific competence of researchers, other researchers, students through practical scientific activities” under Measure No. 09.3.3-LMT-K-712.
Project results:
The photophysical properties of dilute solutions and solid samples will be investigated by both steady-state and time-resolved luminescence spectrometry. Quantum yields of photoluminescence will be determined using an integrating sphere. The charge transfer properties of compound layer will be investigated by time-of-flight method. OLEDs will be formed by vacuum deposition and spin-coating. During the project students will master modern theoretical and experimental research methods such as density function theory, steady and time-resolved luminescence spectroscopy, photoelectron emission spectrometry, time-of-flight method. In addition, student will learn how to form OLEDs and determine their characteristics.
Period of project implementation: 2019-07-01 - 2019-08-31
Project coordinator: Kaunas University of Technology
