Novel Series of Diaminoanthraquinone-Based p-Extendable Building Blocks with Tunable Optoelectronic Properties

We have achieved the first series of DAAQ-based building blocks, viz., n-TIPS-DAAQs (n = 1-4), and unraveled a rational design of their pi-extension. Sequentially increasing numbers (n) of the exocyclic pi-linkers showed (a) a systematic bathochromic shift in both absorption and emission spectra, (b) selective stabilization of the lowest-unoccupied molecular orbital (LUMO), and (c) unselective changes in the S-0/S-1 states. To our surprise, the LUMO level of 4-TIPS-DAAQ (-3.72 eV) was found to be comparable to that of PC60BM.