Resonant Raman scattering of Er 3+ doped and partially isomerized polyacetylene

Abstract

The results of experimental studies of resonant Raman scattering (RRS) spectra from Er 3+ implantation doped and partially isomerized polyacetylene are presented. Thin cis-(CH) x films were synthesized by the method of rare earth complex catalysis polymerization. Doping technique is ion implantation. The surface density of implanted Erbium ion is about 5×10 13/cm 2. In the case of cis-(CH) x, RRS bands at 1160, 1270 and 1540 cm −1 have been observed λ L = 488 nm (10K) and it was shown clearly that a shift in frequency of the peaks assigned to the remaining trans segments occurs during the isomerization process. In the case of Er 3+ doped cis-(CH) x, Er 3+ induced Raman bands at 1145, 1320 and 1510 cm −1 have been measured ( λ L = 488 nm, RT) for the first time and it is observed that the Raman bands from Er 3+ doped trans/cis-(CH) x are shifted to lower frequencies. We point out that the effect of Er 3+ dopant is associated with the defects. The experimental results are discussed by using the model based on the hypothesis that the sample properties can be interpreted in terms of a bimodal distribution of long and short conjugation length segments (for trans-(CH) x) and the bipolaron microscopic model on the basis of multi-phonon lattice relaxation theory (for cis-(CH) x). Our studied results support further the bimodal distribution model and the bipolaron microscopic model.