• 文献标题:   Charge transport in cove-type graphene nanoribbons: The role of quasiparticles
  • 文献类型:   Article
  • 作  者:   CASSIANO TDA, DE SOUSA LE, RIBEIRO LA, SILVA GME, NETO PHD
  • 作者关键词:   ssh, graphene, polaron, bipolaron, charge transport, gnr
  • 出版物名称:   SYNTHETIC METALS
  • ISSN:   0379-6779
  • 通讯作者地址:  
  • 被引频次:   2
  • DOI:   10.1016/j.synthmet.2022.117056 EA MAR 2022
  • 出版年:   2022

▎ 摘  要

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.