Dimensionality-dependent charge transport in close-packed nanoparticle arrays: from 2D to 3D

Abstract

Charge transport properties in close-packed nanoparticle arrays with thickness crossing over from two dimensions to three dimensions have been studied. The dimensionality transition of nanoparticle arrays was realized by continually printing spatially well-defined nanoparticle monolayers on top of the device in situ. The evolution of charge transport properties depending on the dimensionality has been investigated in both the Efros-Shaklovskii variable-range-hopping (ES-VRH) (low temperature) regime and the sequential hopping (SH) (medium temperature) regime. We find that the energy barriers to transport decrease when the thickness of nanoparticle arrays increases from monolayer to multilayers, but start to level off at the thickness of 4–5 monolayers. The energy barriers are characterized by the coefficient βD at ES-VRH regime and the activation energy Ea at SH regime. Moreover, a turning point for the temperature coefficient of conductance was observed in multilayer nanoparticle arrays at high temperature, which is attributed to the increasing mobility with decreasing temperature of hopping transport in three dimensions.

Long-Range Order in Nanocrystal Assemblies Determines Charge Transport of Films

“…14 Similar effects are observed in ethanedithiol-exchanged PbSe NC-based FETs that are moderately conductive and ambipolar in the dark. 39…”

Role of intermolecular charge delocalization and its dimensionality in efficient band-like electron transport in crystalline 2,5-difluoro-7,7,8,8-tetracyanoquinodimethane (F2-TCNQ)

“…36 For the crystals of didodecyl-BTBT isomers, an unprecedented m was observed for the compound with 2D transport and J max B 60 meV, while the compound with an extremely large J max = 129 meV but 1D transport exhibited a 340-fold lower m. 37 Moreover, the same trend of m increase with charge transport dimensionality was observed for arrays of nanoparticles. 38 Noteworthily, the hopping model was unable to describe the data from ref. 37 even qualitatively, and only the band model considering charge delocalization reproduced the strong positive impact of charge transport dimensionality on m.…”

Electron transport through a metallic nanoparticle assembly embedded in SiO2 and SiNx by low energy ion implantation

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