Executive Summary : | The proposed project aims to harvest ambient triplet excitons from an arylene diimide derivative based on pyromellitic diimide using a non-covalent through space charge-transfer (TSCT) approach. This method has numerous applications in organic light-emitting diodes (OLEDs), bioimaging, sensing, and information encryption. Triplet excitons are typically harvested through phosphorescence and thermally activated delayed fluorescence processes. The project aims to achieve charge-transfer (CT) based triplet exciton harvesting by using a through-space approach, where donor and acceptor molecules come to proximity through intermolecular interactions. This long-range molecular ordering helps form stable singlet and triplet charge-transfer states by offsetting vibrational dissipation losses. The strategy is unique and efficient by stabilizing triplet CT states in the CT co-crystal and enhancing intersystem crossing through intermolecular interactions between donor and acceptor molecules. To achieve this objective, the design and synthesis of various core-substituted pyromellitic diimide-based acceptors (cPmDIs) and their subsequent photophysical studies are proposed. The TSCT-based approach will be used to harness triplet excitons from donor-acceptor systems via room-temperature phosphorescence (RTP) or thermally activated delayed fluorescence (TADF) under ambient conditions. A wide range of donors will be used to tune the TSCT-based emission by modulating the electronic properties of the donor. The same strategy-based circularly polarized phosphorescence (CPP) and circularly polarized TADF (CP-TADF) can be realized by using an acceptor based on a chiral core to which pyromellitic diimide (PmDI) is appended. |