点击次数：

论文类型：期刊论文

发表时间：2015-11-01

发表刊物：DYES AND PIGMENTS

收录刊物：EI、SCIE、Scopus

卷号：122

页面范围：286-294

ISSN号：0143-7208

关键字：Aza-boron-dipyrromethene; Heavy atom effect; Ultrafast pump probe spectroscopy; Intersystem crossing; Two photon absorption; Z-scan technique

摘要：New aza-boron-dipyrromethene compounds containing bromine atoms at various positions were designed and synthesized to enhance the triplet state population and two photon absorption properties for applications such as two-photon photodynamic therapy, triplet triplet annihilation up-conversion. Steady state fluorescence and ultrafast pump probe spectroscopy techniques revealed that only 2, 6 positions of aza-boron-dipyrromethene core contribute to triplet state population significantly. Density function theory calculations showed that when bromine atoms introduced to 2, 6 position of aza-boron-dipyrromethene core, singlet and triplet energy levels get closer therefore probability of intersystem crossing increases. Z-scan experiments at 800 nm wavelengths revealed considerably large (610 GM) two photon absorption cross section value with respect to literature for compounds showing intersystem crossing mechanism. The efficient intersystem crossing and enhanced two-photon absorption properties make the investigated aza-boron-dipyrromethene compounds good candidates for two-photon photodynamic therapy application. (C) 2015 Elsevier Ltd. All rights reserved.