Study of electronic and vibronic contributions to cooperative enhancement of two-photon absorption in multibranched structures

Abstract

A series of multibranched benzylidene cyclopentanone dyes with non-conjugated central moiety were synthesized. Their one- and two-photon photophysical properties were systematically studied in comparison with corresponding triphenylamine derivatives. Electronic coupling and vibronic coupling contributions to cooperative enhancement of two-photon absorption in multibranched structure were revealed. The results showed that the crucial contribution for this enhancement was from electronic coupling effect among branches. In addition, no contribution of vibronic coupling was observed. Furthermore, multibranched effect on photosensitizing efficiency of these compounds was investigated by one-photon polymerization and the result indicated the electronic coupling effect was also beneficial to their photosensitizing efficiency.