期刊
SYNTHETIC METALS
卷 287, 期 -, 页码 -出版社
ELSEVIER SCIENCE SA
DOI: 10.1016/j.synthmet.2022.117056
关键词
SSH; Graphene; Polarons; Bipolarons; Charge transport; GNR
资金
- Brazilian Research Councils CNPq [304637/2018-1]
- CAPES
- FAPDF [0193.001662/2017, 0193.001766/2017]
- CNPq [304637/2018-1]
- VILLUM FONDEN [00028053]
Previous reports indicate the high intrinsic charge mobility of cove-type graphene nanoribbons (CGNR). In this study, the charge transport in 4-CGNR was simulated, considering the lattice collective behavior. The simulation revealed the presence of two quasiparticles: polaron and bipolaron. The model derived mobilities for polarons and bipolarons reached up to 18,000 cm(2)/Vs and 1500 cm(2)/Vs, respectively. These carriers exhibited high efficiency and low effective mass, making CGNR a potential base material for future optoelectronic devices.
Previous reports indicate that cove-type graphene nanoribbons (CGNR) may present high intrinsic charge mobility of almost 15,000 cm(2)/Vs. Still, with experimental estimates varying from 150 to 15,000 cm(2)/Vs. Typically, theoretical mobilities are obtained from methods such as the Drude-Smith model, which tends to neglect the electron-phonon coupling mechanism, or the Boltzmann transport equation, that considers only acoustic phonons. As such, more thorough approaches are needed. In this work, we simulated charge transport in 4-CGNR by explicitly contemplating the lattice collective behavior. The nanoribbon is simulated by a twodimensional Su-Schrieffer-Heeger (SSH) tight-binding model with electron-phonon coupling and considering all phonon modes. Results show the rise of two quasiparticles: polaron and bipolaron. We probed their dynamical properties by including the presence of an external electric field. Findings indicate that each carrier has a characteristic transport regime that is deeply related to phonon collision interactions. Model derived mobilities for polarons and bipolarons reach up to 18,000 cm(2)/Vs and 1500 cm(2)/Vs, respectively. Furthermore, calculations reveal the carriers to be highly efficient charge transporters, with a field independent low effective mass and notable mobility, delivering a better performance than other narrow GNRs. All presented features place the CGNR as a potential base material of future high-quality organic-based optoelectronic devices. The work also contributes to the theoretical understanding of transport physics in highly confined materials.
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