Executive Summary : | Organic emitters have widespread applications in the field of optoelectronic devices such as organic photovoltaics (OPVs)¬¬¬, organic light emitting diodes (OLEDs) etc. Owing to their pre-eminent low power consumption, mechanical flexibility, they have successfully headed towards commercialization. Compared to first generation fluorescent emitters with internal quantum efficiency limited to 25% and second generation phosphorescent emitters which although offer higher quantum efficiency but involve heavy metal complexes associated with higher costs, third generation metal-free pure organic emitters exhibit thermally activated delayed fluorescence allowing internal quantum efficiency to reach nearly 100% and are promising luminescent material for fabrication of corresponding devices. In this work, it is proposed to develop donor-acceptor compounds based on heterocyclic donors and acceptors and integrated via variety of linkers are proposed for realizing thermally activated delayed fluorescence. It is also proposed to study the effects of change of dihedral angles between planes of donor and acceptor units on excitations to relate with frontier orbital overlap which directly impact the singlet-triplet splitting (〖ΔE〗_ST). Imidazopyrazine, imidazopyrimidine, triazolopyridine, triazolopyrimidine and triazolopyrazine are proposed as acceptor unit in the new design of TADF emitters. Tuning the functional properties are proposed by changing the nature of donor, nature of linker, and by post chemical modification of appropriate reactions. Effects of substitutions on the twisting angles and their influence on the electronic properties will be thoroughly investigated using computational studies and photophysical measurements. Promising TADF emitters will be applied as emitters in OLED and photocatalysts for organic transformations. Aryl radical generation reactions will be investigated using the potential sensitizers. |