Electrospun Mn₂O₃ Nanofiber Networks as Bio-Transducers: Electrical Characterization, Modeling, and DNA Sensing

Abstract

In this work, we report the synthesis and electrical characterization of electrospun manganese III oxide (Mn2O3) nanofibers and their application in chemiresistive biosensing. Here, the Mn2O3 nanofibers, which are inherently p-type semiconductors with a direct bandgap in the order of 1.2–1.4 eV, are drop cast across interdigitated electrodes to create the desired chemiresistive networks. Their I–V characteristics are governed by space charge limited current, attributing to nonlinear behavior at higher voltages. However, in the range of ±0.5 V, near-linear behavior is observed. Here, we have used an analogous R–C network to explain the low- and high-frequency behavior of the said nanofibers under different applied-bias conditions. Furthermore, the effect of temperature on the said nanofibers’ conductive properties is investigated, and the corresponding Arrhenius activation energy is derived. We have also explored the conductance–temperature dependence concerning the nanofiber network and have analyzed the potential carrier transport mechanisms. Also, operating in the near-linearity window, we have developed a chemiresistive protocol for DNA sensing. Mn2O3 nanofibers decorated with single-stranded probe DNAs act as transducers for surface hybridization with target nucleotides. The DNA sensing carried out in this work has a dynamic concentration range of 10 fM to 10 nM, with a linear response between 100 pM and 10 nM.