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

In this work, we report the synthesis and electrical characterization of electrospun manganese III oxide (Mn
₂
O
₃
) nanofibers and their application in chemiresistive biosensing. Here, the Mn
₂
O
₃
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. Mn
₂
O
₃
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.