Organic Donor-Acceptor Conjugates: Thermally Activated Delayed Fluorescence, Room-Temperature Phosphorescence and Modulation of Fluorescence Lifetimes via Conformational Switching | Shiv Nadar University

Organic Donor-Acceptor Conjugates: Thermally Activated Delayed Fluorescence, Room-Temperature Phosphorescence and Modulation of Fluorescence Lifetimes via Conformational Switching

Organic light emitting materials holds great promise for display devices and biological detection. The first chapter of the thesis focusses on design principle of such emitters. Second chapter deals with dual emission of carbazole-quinoline conjugate that exhibits both TADF via reverse intersystem crossing (rISC) from the higher-lying triplet state (T2) to the singlet state (S1) and RTP from the lowest triplet state (T1). Furthermore, we have discovered a novel thermal enhancement mechanism of emission enhancement above room-temperature. This mechanism rely on thermal-induced conformational change that compensates the emission losses due to non-radiative transitions at elevated temperatures. In the third chapter, we have shown how intrinsic triplet energy level can be tuned by external command (mechanical force). Forth chapter of the thesis discusses intermolecular charge transfer (I2CT) in a single component system. Based on this design principle we have shown room-temperature phosphorescence in the red part of the spectrum at ambient conditions. The last chapter discusses tuning of emission lifetime of a coumarin-imidazole conjugate appended with –OH group. We have shown that conformational switching which is controlled by a remote intramolecular H-bonding interaction within the backbone in a coumarin conjugate is a key mechanism for achieving lifetime alteration of the dye. 

Department: 
Chemistry
Year: 
2018
Student Name: 
Indranil Bhattacharjee
Faculty Advisor: 

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