Title :
Novel electrical and optical properties of discotic liquid crystals, substituted phthalocyanine rare-earth metal complexes
Author :
Yoshino, K. ; Sonoda, T. ; Lee, S. ; Hidayat, R. ; Nakayama, H. ; Tong, L. ; Fujii, A. ; Ozaki, M. ; Ban, K. ; Niskizawa, K. ; Ohta, K.
Author_Institution :
Dept. of Electron. Eng., Osaka Univ., Japan
Abstract :
Akylthio-group-substituted phthalocyanine rare-earth metal sandwich complexes such as bis[octakis(alkylthio)phthalocyanineato]europium(III) {[(CnS) 8Pc]2Eu}, bis[octakis(alkylthio)phthalocyaninato]lutetium(III) {[(CnS) 8Pc]2Lu}, bis[octakis(alkylthio)phthalocyaninato]terbium(lII) {[(CnS) 8Pc]2Tb} exhibit discotic liquid crystal phases. Photoluminescence (PL) peaks of [(CnS)8Pc]2 Eu were observed at around 400-600 nm and 730 nm in chloroform solution. However, the strong narrow emission of the Eu3+ ion was not observed compared with other Eu-complexes. The intensity and the decay time of the PL peak depend strongly on the phase. They have been explained by taking electronic energy schemes of both phthalocyanine ligands and the Eu3+ ion into consideration. The role of the triplet exciton is also discussed. In the photoconductivity (PC) spectra of [(CnS)8Pc]2Eu several peaks were observed corresponding to the absorption peaks. The behavior has been discussed in terms of carrier migration along the stack of phthalocyanine cores in the discotic phase. Current-voltage characteristics and dielectric properties of these discotic liquid crystals have also been clarified
Keywords :
dielectric liquids; discotic liquid crystals; excitons; organometallic compounds; photoconductivity; photoluminescence; rare earth compounds; spectral line intensity; 400 to 600 nm; 730 nm; Eu3+ ion emission; I-V characteristics; PL peak decay time; PL peak intensity; [(CnS)8Pc]2Eu; [(CnS)8Pc]2Lu; [(CnS)8Pc]2Tb; absorption peaks; akylthio-group-substituted phthalocyanine rare-earth metal sandwich complexes; bis[octakis(alkylthio)phthalocyaninato]lutetium(III); bis[octakis(alkylthio)phthalocyaninato]terbium(lII); bis[octakis(alkylthio)phthalocyanineato]europium(III); carrier migration; chloroform solution; current-voltage characteristics; dielectric properties; discotic liquid crystals; electrical properties; electronic energy schemes; optical properties; photoconductivity spectra; photoluminescence peaks; phthalocyanine cores; phthalocyanine ligands; substituted phthalocyanine rare-earth metal complexes; triplet exciton; Laser mode locking; Liquid crystal polymers; Liquid crystals; Optical films; Optical mixing; Optical pulses; Semiconductor laser arrays; Space vector pulse width modulation; Ultrafast optics; X-ray lasers;
Conference_Titel :
Dielectric Liquids, 1999. (ICDL '99) Proceedings of the 1999 IEEE 13th International Conference on
Conference_Location :
Nara
Print_ISBN :
0-7803-4759-5
DOI :
10.1109/ICDL.1999.799006
