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Novel photoresponsive materials for ultrafast absorption changes in the visible and near infrared regions



연 사 : Prof. Toshihiko Nagamura (일본 시즈오까 대학)



Ion-pair charge-transfer (IPCT) complexes were formed between redox active cations such as 4,4'-bipyridinium and styrylpyridinium with appropriate anions such as halides or tetraarylborates, which showed specific absorption in the visible region. Upon excitation of the IPCT band with femtosecond (fs) laser, electron transfer occurred instantaneously from a donor anion to an acceptor cation. The lifetime of photogenerated was controlled over an extremely wide rage from about 1 picosecond to infinity by counter anions and microenvironments. Styrylpyridinium ions with an electron-withdrawing group in a phenyl ring showed specific absorption bands both in the visible and near infrared regions upon photoinduced electron transfer from counter

anions. The latter was attributed to the charge resonance (CR) band of dimer radical cations formed via electronic interactions between a photogenerated styrylpyridinyl radical and a parent styrylpyridinium cation. The lifetime and wavelength of the CR band were controlled over a very wide range by substituents and conformation.





세미나 문의 : 박수영 교수 (880-8327)



일 시 : 2001. 11월 28일(수) 오후 5:00-6:00

장 소 : 신소재 제1세미나실