Toward panchromatic organic functional molecules: density functional theory study on the electronic absorption spectra of substituted tetraanthracenylporphyrins

To achieve full solar spectrum absorption of organic dyes for organic solar cells and organic solar antenna collectors, a series of tetraanthracenylporphyrin derivatives including H(2)(TAnP), H(2)(α-F(4)TAnP), H(2)(β,β'-F(8)TAnP), H(2)(γ,γ'-F(8)TAnP), H(2)(δ,δ'-F(8)TAnP), H(2)α-(NH(2))(4)TAnP], H(2)β,β'-(NH(2))(8)TAnP], H(2)γ,γ'-(NH(2))(8)TAnP], and H(2)δ,δ'-(NH(2))(8)TAnP] was designed and their electronic absorption spectra were systematically studied on the basis of TDDFT calculations. The nature of the broad and intense electronic absorptions of H(2)(TAnP) in the range of 500-1700 nm is clearly revealed, and different types of π → π* electronic transitions associated with different absorption bands are revealed to correspond to different electron density moving direction between peripherally fused 14-electron-π-conjugated anthracene units and the central 18-electron-π-conjugated porphyrin core. Introduction of electron-donating groups onto the periphery of the H(2)(TAnP) macrocycle is revealed to be able to lead to novel NIR dyes such as H(2)α-(NH(2))(4)TAnP] and H(2)δ,δ'-(NH(2))(8)TAnP] with regulated UV-vis-NIR absorption bands covering the full solar spectrum in the range of 300-2400 nm.