Novel Series of Diaminoanthraquinone-Based π‑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 π-extension. Sequentially increasing numbers (n) of the exocyclic π-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 S0/S1 states.
To our surprise, the LUMO level of 4-TIPS-DAAQ (−3.72
eV) was found to be comparable to that of PC60BM.