Investigation of the charge complex formation of novel silicon-based copolymers containing carbazole unit by time-resoved laser spectroscopic technique in the electronic excited state

Abstract

SiPhPVK has unusual photophysical characterisitcs that are attributed to the formation of charge transfer complex in the excited state. The photoluminescence (PL) and excitation spectra for SiPhPVK at emission wavelengths of 440 and 520 nm were compared with those for SiHMPVK. Two excitation spectra of SiPhPVK monitored at two probes were observed different obviously. However, the excitation spectra of SiHMPVK obtained at two different probes showed the same spectral feature. In addition, upon photoexcitation with 300 run, the PL life time of SiPhPVK became longer with increasing the probe wavelength. Expeimental data suggest that the electron transfer can occur from carbarzole to SiPh unit of SiPhPVK to generate the stabilized excited state. However, the PL decay profiles of SiHMPVK exhibited almost same at all probes with photoexcitation of 325 nm. Therefore, the PL emission of SiHMPVK at 325 mainly results from carbazole segments.