Synthesis, characterization, two-photon absorption, and optical limiting properties of triphenylamine-based dendrimers

Abstract

Three π-conjugated dendrimers (Ph-G0, Ph-G1 and Ph-G2) bearing triphenylamine moieties have been synthesized through a convergent synthetic strategy without any protection–deprotection chemistry. The linear photophysical properties, two-photon absorption (TPA), and optical limiting behavior of the dendrimers were investigated in solution at room temperature. Linear absorption and emission spectra revealed a bathochromic shift and decreased fluorescence quantum yields with increasing dendrimer generation. A strong cooperative effect in the TPA absorption of these dendrimers was observed. The TPA cross-sections increase gradually with the proportion of triphenylamine units and the maximum value of the TPA cross-section can reach 5690 GM for Ph-G2. These triphenylamine-based dendrimers exhibited efficient two-photon optical limiting under femtosecond excitation.