Synthesis and studies of high-triplet-energy materials for blue OLEDs


Call Mutual funds Taiwan – Latvia – Lithuania, 2016
Implementation period 01.01.2017. – 31.12.2019.
Project partners Kaunas University of Technology, Lithuania
Latvian Institute of Organic Synthesis, Latvia
Graduate Institute of Photonics and Optoelectronics, Taiwan
Leader of Latvian team Dr. Pavel Arsenyan
Total costs 202 500 EUR
Costs for Latvian partner 67 500 EUR


During the last decades, all colour organic light-emitting diodes (OLEDs) have evolved into commercial applications such as flat-panel low-weight displays or sources of solid state lighting. Today, the efficiency of OLEDs is at product-relevant levels for all colours excepting blue. Therefore, high-efficient blue OLEDs with industry-standard device lifetimes have to be realized to fully open the potential of OLEDs. Recently blue thermally activated delayed fluorescence (TADF) and phosphorescence emitters (having values of triplet levels higher than 2.7 eV) were developed application of which can allow to achieve the internal quantum efficiency of blue OLEDs close to 100 %.

The project will be undertaken by the combined efforts of the partners the expertise of which covers the fields of chemistry, physics, and materials science. The project partners have a wide range of backgrounds: from quantum chemical calculations, synthetic organic chemistry, materials characterization, photoelectrical and optical analyses of organic materials to organic thin film processing and device fabrication and characterization. The tasks of the project include development of high efficiency organic semiconductor materials with high triplet-energy values for new-generation blue OLEDs including the theoretical modelling and designing of charge-transporting materials, their synthesis and characterisation, investigation of thermal, electrochemical, electronic, optical, photophysical properties of the organic semiconductors, characterization of charge transport properties in solid state, detailed investigation of transport mechanisms and correlation with molecular structures and morphology etc., fabrication and characterization of light-emitting devices using the most promising materials. OLEDs with the maximum external quantum efficiency (EQE) higher than 15 % will be fabricated and characterised. The turn on voltage of the OLEDs will be lower than 3.5 V. The maximum brightness higher than 5000 cd/m2 will be reached that will unclose the practical applications of blue OLEDs. The current (ηc) and power (ηp) efficiencies of the devices will be higher than 30 cd/m2 and 20 lm/W, respectively.