Theoretical molecular engineering for nonlinear absorption by two-photon absorption in the visible

A molecular engineering strategy is developed around bis(di-n-methylamino)-E-stilbene 1 in order to design efficient two-photon absorbers in the visible range. This strategy is based on the role of the charge transfer conjugated system, and of donor substituents on theoretical linear and two-photon absorption (TPA). The best trade-off TPA-linear absorption is fulfilled by two tetraphephenyl-diamine derivatives (biphenyl and fluorene), which could allow, if mixed, efficient coverage of the visible range.