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Design and Fabrication of high efficiency red OLEDs

Design and Fabrication of high efficiency red OLEDs

Date23rd Mar 2021

Time02:00 PM

Venue Google Meet

PAST EVENT

Details

Organic light emitting diodes (OLEDs) have drawn the attention of researchers because of its increase in demand in the display industry. Due to the limitations of the IQE ( 25 %) in fluorescent OLEDs, third generation OLEDs, called thermally activated delayed fluorescent (TADF) OLEDs, are being explored. TADF materials are prone to concentration quenching effects. Hence employing TADF materials alone in the emissive layer leads to poor performance of the OLED. A guest- host matrix arrangement in the emissive layer is employed so as to overcome the quenching effects. In this study, a near infra red thermally activated delayed fluorescence (TADF) molecule 7,10-Bis(4-(diphenylamino)phenyl)-2,3-dicyanopyrazino phenanthrene (TPA-DCPP) is used as light emitting material(guest). A detailed analysis of the choice of host that is to be employed in the guest-host matrix of the emissive layer of the OLED is presented. The doping concentration of the guest in the emissive layer is optimized by photoluminescence (PL) studies. Charge injection layers play a significant role in maintaining the charge balance thereby resulting in high efficiencies. In this study we present a comparative analysis of 1,4,5,8,9,11-Hexaazatriphenylenehexacarbonitrile (HATCN) and Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) PEDOT: PSS as hole injection layers and their effect on device efficiency and charge balance in the emissive layer of the device stack. From this study, red TADF OLEDs with a maximum external quantum efficiency of 13.2 % at a luminance of 1 cd/m2 is demonstrated.

Speakers

Inaganti Naga Sai Manoj (EE18S022)

Electrical Engineering