Organic Donor Acceptor Conjugates Thermally Activated Delayed Fluorescence persistent Phosphorescence and Thermally Enhanced Emission for Accessing Organic Light Emitting Diodes White Light Emission and Data Security

Abstract

Triplet energy harvesting at ambient conditions from the organic semiconductors is of utmost importance for organic light-emitting diodes (OLEDs), sensing, bio-imaging, photocatalyst, and data security applications. Thermally activated delayed fluorescence (TADF) and room temperature phosphorescence (RTP) are two elegant photophysical processes that can harvest radiative triplet energy that holds great promise in many applications.The introductory chapter of the thesis focuses on the design principle of organic light emitters that can harvest triplet energy at ambient conditions. The second chapter deals with phenothiazine-quinoline (Donor-Acceptor, D-A) conjugates realizing intrinsic TADF and RTP at ambient conditions. .The third chapter of the thesis discusses how intramolecular Fröster-type energy transfer in halogen-substituted D-A conjugates could enhance the photoluminescence quantum yield at elevated temperatures (gt RT), which is a challenging problem in photophysics. The fourth chapter of the thesis deals with the ideal white light emission using simultaneous emission of blue-TADF and orange-TADF emitters in a single emissive layer. The last chapter of the thesis discusses how the dark triplet states of a non-TADF system can be harvested via host-sensitized multiple triplet-to-triplet energy transfer (TTET) mechanisms.