Executive Summary : | The study focuses on the efficient photoresponsive and light-harvesting compounds made up of multichromophoric electron donors and acceptors, which are promising materials for optoelectronic devices. The efficiency of these compounds can be modified by controlling the localization of excitation. Extensive research is being conducted to understand the effect of exciton (de)localization in push-pull derivatives and natural light-harvesting complexes. The excited state symmetric breaking (ESSB) is a key phenomenon in multibranched electron donor-acceptor derivatives, which is used in various applications such as photopolymerization, photovoltaic, and organic light emitting diodes. ESSB is mainly employed in photosynthesis, where sunlight energy is transferred by the enzyme to the reaction active center. However, the occurrence of ESSB has not been fully explored in relation to its dynamics and target systems. The project begins with the synthesis of multibranched electronic donor and acceptor derivatives with an architecture of (D-π)₄-A and D-π-A-π-D, consisting of carbazole or phenoxazine electron donors and oxadiazole or diphenyl pyrazine electron acceptors linked via ethynyl bridges. The steady state and time-resolved photophysical characterization of the compounds will be measured to understand the intermediates involved in the excited state relaxation pathways. The time-resolved IR vibrational spectra of multipolar derivatives will be measured to illustrate the mechanism, dynamics, electronic coupling, and orientation of derivatives upon the ESSB. The outcome of the proposal will reveal the underlying mechanism and factors controlling the ESSB of organic multibranched electronic donor and acceptor systems, which are significant considerations for the design of materials used in optoelectronic devices. |