https://doi.org/10.1140/epjb/e2017-80018-7
Regular Article
The effects of temperature on the formation and stability of bipolarons in conjugated polymers
1 Department of Physics and Electromagnetic Transport Materials Laboratory, Xingtai University, Xingtai 054001, P.R. China
2 College of Information Science and Engineering, Hebei Engineering Research Center for Information Technology in Population Health, Hebei North University, Zhangjiakou 075000, P.R. China
3 College of Physics and Hebei Advanced Thin Films Laboratory, Hebei Normal University, Shijiazhuang 050016, P.R. China
a
e-mail: my882154@126.com
b
e-mail: zan@mail.hebtu.edu.cn
Received: 9 January 2017
Received in final form: 5 March 2017
Published online: 12 April 2017
Within the one-dimensional tight-binding Su-Schrieffer-Heeger (SSH) model modified to include thermal effects and electron-electron interactions, the transition from polaron to bipolaron and the formation of bipolaron induced by injecting charges are separately simulated using a nonadiabatic evolution method. For the transition process, it is found that with the temperature effects taken into account, two separate polarons with the same charge and antiparallel spins can recombine into a bipolaron. The results show that with the temperature increasing, the time taken for the recombination of two polarons decreases. The effects of different distances between the polarons are also numerically simulated. For the bipolaron formation, we investigate the evolution of two charges injected into a polymer chain with the thermal effects. We find that the bipolaron is always quickly formed and its dynamical stability is less sensitive to the temperature change. Thermal effects can only affect the degree of the charges localization.
Key words: Solid State and Materials
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2017
