Tuning the optoelectronic properties of PEDOT:PSS – PVP core-shell electrospun nanofibers by solvent - quantum dot doping and phase inversion.

: In the present study core-shell PEDOT:PSS-polyvinylpirrolidone nanofibers were synthesized by coaxial electrospinning. These fibers were doped with different solvents (dimethylsulphoxide, dimethyl sulfoxide (DMSO), isopropyl alcohol (IPA), and ethylene glycol), and PbS nanoparticles at different concentrations; additionally, the coaxial electrospinning setup process was inverted in order to exchange the phases comprising the core-shell morphology. Experimental results showed that DMSO and IPA solvents produced a change in the PEDOT:PSS phase from its benzoid structure to a more conjugated (quinoid) one. The synthesized samples displayed an increment in the conductance of the composite nanofibers, based on a more conjugated structure of the PEDOT:PSS phase, and a better dispersion of the PbS nanoparticles within the nanofibers; this increment was, under certain synthesis conditions, up to three orders of magnitude higher than in the case of the nanofibers with no solvent, nor nanoparticles, added. Photoresponse also showed a clear increment in the value of the photogenerated current as the concentration of the nanoparticles increased. Inverting the arrangement of the core-shell phases in the nanofibers increased the conductance and the photogenerated current in the cases analyzed. These results show novel evidence on the capability of tuning the conductance and photoresponse of composite core-shell nanofibers, based on the doping of the PEDOT:PSS phase with different solvents and PbS nanoparticles, and the arrangement of the core-shell phases. Tailoring the optoelectronic properties of conductive, flexible nanofibers is a desirable competence in technological areas such as transparent flexible conductors, biosensors and tissue engineering.