# Photoluminescence of _Cis_-Polyacetylene Semiconductor Material
## 1 Introduction
Analysis of the integrated photoluminescence intensities indicated that the percolation threshold for free carriers was achieved at just 30% overall _trans_ content, implying that thermally isomerized polyacetylene behaved more like a three-dimensional composite material than a one-dimensional material [7]. [PERSON] et al. [8] explored the emission properties of _cis_- and _trans_-polyacetylene, which was controlled by the ratio of _cis_- and _trans_-polymers. They found that the emission efficiency and PL lifetime decreased with an increase in _cis_ content. [PERSON] et al. explained the characterization of PL (photoluminescence) and EL (electroluminescence) by using polyacetylene derivatives. They experimentally proved that intensity of PL and the spectrum were dependent on the PA and various electrode configurations [9]. [PERSON] et al. studied the PL and EL of the mixtures of PA and found a remarkable spectral shift in PL and EL [10]. [PERSON] et al. [11] studied the computational examination of _trans_-polyacetylene oligomers, which was based on the electron vibrational dynamics of molecular systems. [PERSON] et al. [12] investigated the nonadiabatic contributions to the vibronic sidebands of equilibrium and explicitly time-resolved nonequilibrium photoelectron spectra for a vibronic model system of _trans_-polyacetylene. They explained how the vibronic wavepacket motion of the model could be located in the time-resolved photoelectron spectra as a function of the pump-probe delay. [PERSON] et al. [13] explained that after modification, \(\pi\)-conjugated polymers such as PA could be used for optoelectronics applications. Because of electronic correlation effects and strong electron-phonon interactions, the theoretical description of \(\pi\)-conjugated polymers is very complicated. From the previous studies on polyacetylene, it can be understood that [14; 15] that coupling of the electrons to the nuclear degrees of freedom results depends on the semiconductor or crystalline metal materials of the PA. [PERSON] et al. [16] observed strong coupling to the nuclear degrees of freedom of the excited state electron nuclear dynamics of a polyacetylene chain. They explained the photoexcitation dynamics of conjugated _cis_-polyacetylene oligomers using an ESMD quantum chemical approach, and found that the excitation moves to the lowest electronic energy and creates phonon excitations and significant local distortions towards the lattice. [PERSON] et al. [17] made a polymer using polyacetylene and experimentally proved that the polymer, which was prepared from polyacetylene, showed higher (352 nm) UV-visible absorption characteristics, and its highest photoluminescence spectrum was at 453 nm, which corresponds to the photon energy of 2.74 eV. [PERSON] et al. [18] reported the synthesis and properties of a new polyacetylene-based polyelectrolyte. The absorption spectrum exhibited a maximum absorption value of 480 nm, which was due to the p\(\rightarrow\)p\({}^{*}\) transition of the conjugated polymer backbone. The photoluminescence spectra of the polymer exhibited a maximum peak of 550 nm, which corresponded to a photon energy of 2.26 eV. Typical irreversible electrochemical behaviors were observed between the doped and undoped peaks in the cyclic voltammograms of the polymer. In this study, we have considered a simple single oligomer model of _cis_-polyacetylene to investigate interfacial electron transfer in the system, and representative nuclear configurations were obtained according to ab initio DFT molecular dynamic simulations and the time-dependent electronic structure. We considered the relaxation rates of photoexcited electrons and holes for our simulation using ab initio treatment of the electronic states when the underlying nonadiabatic transitions are accompanied by the respective vibrational dynamics. For this calculation, we used the Redfield theory for the calculation of the on-the-fly nonadiabatic couplings.