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Cation–π Interaction Assisted Molecule Attachment and Photocarrier Transfer in Rhodamine/Graphene Heterostructures
Author(s) -
Liu Bo,
LópezGonzález Luis E.,
Alamri Mohammed,
VelázquezContrera Enrique F.,
SantacruzOrtega Hisila,
Wu Judy Z.
Publication year - 2020
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.202000796
Subject(s) - graphene , rhodamine 6g , materials science , molecule , electron transfer , chemical physics , photochemistry , nanotechnology , chemistry , organic chemistry
Cation–π interactions between molecules and graphene are known to have a profound effect on the properties of the molecule/graphene nanohybrids and motivate this study to quantify the attachment of the rhodamine 6G (R6G) dye molecules on graphene and the photocarrier transfer channel formed across the R6G/graphene interface. By increasing the R6G areal density of the R6G on graphene field‐effect transistor (GFET) from 0 up to ≈3.6 × 10 13 cm −2 , a linear shift of the Dirac point of the graphene from originally 1.2 V (p‐doped) to −1 V (n‐doped) is revealed with increasing number of R6G molecules. This indicates that the attachment of the R6G molecules on graphene is determined by the cation–π interaction between the NH+ in R6G and π electrons in graphene. Furthermore, a linear dependence of the photoresponse on the R6G molecule concentration to 550 nm illumination is observed on the R6G/graphene nanohybrid, suggesting that the cation–π interaction controls the R6G attachment configuration to graphene to allow formation of identical photocarrier transfer channels. On R6G/graphene nanohybrid with 7.2 × 10 7 R6G molecules, high responsivity up to 5.15 × 10 2 A W −1 is obtained, suggesting molecule/graphene nanohybrids are promising for high‐performance optoelectronics.