The present study reports the synthesis of polypyrrole/molybdenum disulphide-reduced graphene oxide (PPy/MoS2-rGO abbreviated as PMG) ternary nanocomposites through chemical method using different loading concentrations (5, 10, 15 and 20 wt%) of MoS2-rGO in polypyrrole (PPy) matrix. The synthesized samples have been utilized for the study of electrical conduction and charge transport mechanism in low-temperature region from liquid nitrogen temperature (77 K) to room temperature (300 K). The morphological studies through field emission scanning electron microscopy (FESEM) reveal the growth of nanoribbons of PPy with length of approx. 4–5 μm and width of ~ 200 nm over the three-dimensional porous nanostructures of MoS2-rGO. The Raman spectroscopic investigations on the prepared PMG nanocomposites indicate an increase in the bipolaron to polaron concentration with increasing MoS2-rGO loading content in PPy. The charge transport properties investigated in low-temperature region suggest that the electrical conductivity data follow the three-dimensional Mott’s variable range hopping (MVRH) conduction mechanism in all the prepared nanocomposite samples. The decrease of the Mott’s characteristic temperature and average hopping distance from 2.496 × 106 K to 3.554 × 105 K and from 10.74 × 10–8 cm to 6.601 × 10–8 cm, respectively, whereas the increase of the density of states (<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10854_2025_14954_Article_IEq1.gif" Format="GIF" Height="19" Rendition="HTML" Resolution="72" Type="Linedraw" Width="45" /> </InlineMediaObject> <EquationSource Format="TEX">$N({E}_{F}$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi>N</mi> <mo stretchy="false">(</mo> <msub> <mi>E</mi> <mi>F</mi> </msub> </mrow> </math></EquationSource> </InlineEquation>)) at Fermi level from 3.116 × 1021 to 2.189 × 1022 cm−3 eV−1 indicate the delocalization of charge carriers and in the enhancement of the electrical conductivity with increasing the loading concentration of MoS2-rGO from 5 to 20 wt% in PPy matrix. The understanding of charge transport properties of conjugated polymer-based nanocomposites offers new gateway for the development of next-generation flexible electronic devices.

Mott’s variable range hopping conduction mechanism in polypyrrole/molybdenum disulphide-reduced graphene oxide nanocomposites

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发表日期：

2025年5月27日

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Aarti Rajpal,
Ishpal Rawal,
Anita Sharma,
Sajjan Dahiya,
Vijay Kumar,
Parveen K. Goyal

摘要

The present study reports the synthesis of polypyrrole/molybdenum disulphide-reduced graphene oxide (PPy/MoS₂-rGO abbreviated as PMG) ternary nanocomposites through chemical method using different loading concentrations (5, 10, 15 and 20 wt%) of MoS₂-rGO in polypyrrole (PPy) matrix. The synthesized samples have been utilized for the study of electrical conduction and charge transport mechanism in low-temperature region from liquid nitrogen temperature (77 K) to room temperature (300 K). The morphological studies through field emission scanning electron microscopy (FESEM) reveal the growth of nanoribbons of PPy with length of approx. 4–5 μm and width of ~ 200 nm over the three-dimensional porous nanostructures of MoS₂-rGO. The Raman spectroscopic investigations on the prepared PMG nanocomposites indicate an increase in the bipolaron to polaron concentration with increasing MoS₂-rGO loading content in PPy. The charge transport properties investigated in low-temperature region suggest that the electrical conductivity data follow the three-dimensional Mott’s variable range hopping (MVRH) conduction mechanism in all the prepared nanocomposite samples. The decrease of the Mott’s characteristic temperature and average hopping distance from 2.496 × 10⁶ K to 3.554 × 10⁵ K and from 10.74 × 10^–8 cm to 6.601 × 10^–8 cm, respectively, whereas the increase of the density of states ( $N({E}_{F}$ $N (E_{F}$ )) at Fermi level from 3.116 × 10²¹ to 2.189 × 10²² cm⁻³ eV⁻¹ indicate the delocalization of charge carriers and in the enhancement of the electrical conductivity with increasing the loading concentration of MoS₂-rGO from 5 to 20 wt% in PPy matrix. The understanding of charge transport properties of conjugated polymer-based nanocomposites offers new gateway for the development of next-generation flexible electronic devices.