کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5187654 | 1381134 | 2008 | 8 صفحه PDF | دانلود رایگان |
Geometries, ionization potentials (IPs), electron affinities (EAs) and optical properties of two series of Ï-conjugated oligomers (2,6-(4,4-bis(2-ethylthexyl)-4H-cyclopenta-[def]-phenanthrene))n CPPn (2,6-(4,4-bis(2-ethylthexyl)-8,9-dihydro-4H-cyclopenta-[def]-phenanthrene))n HCPPn (n = 1-4) were studied theoretically. The ground and the excited state geometries were optimized by B3LYP and CIS methods with 6-31Gâ basis sets, respectively. The absorption and the emission spectra were calculated by TD-B3LYP method. The lowest-lying absorption is assigned to Ï â Ïâ transition, and the fluorescence can be described as originating from the 1[ÏÏâ] excited state. IPs, EAs, H-L gaps, absorption and emission properties of PCPP (n = â) and PHCPP (n = â) were obtained by extrapolation method. The fact that the lowest-lying absorption and the emission of PCPP are blue-shifted compared with those of PHCPP, can be interpreted by the smaller effective repeating units of PCPP. The extra absorption band at 289 nm of PCPP is contributed by the Ï â Ïâ transition involving the extra Ï-conjugation CC bond.
Journal: Polymer - Volume 49, Issue 8, 15 April 2008, Pages 2077-2084