Structural, optical and electrical properties of Cu:MnO2 nanostructured thin films for glucose sensitivity measurements

Abstract

In the present investigation, pure MnO2 and Cu doped MnO2 (Cu:MnO2) thin films were successfully prepared by the spray pyrolysis deposition technique. Different Cu concentrations were used to analyze the morphological, structural, optical, electrical properties and as well glucose sensitivity measurement has been performed. MnO2 doped with Cu induces microstructure and is set in the lattice by keeping Mn+2 leading to the micro spherical shape of the samples highlighted from a scanning electron microscope. X-ray diffraction analysis has confirmed the tetragonal MnO2 crystal structure with α-phase. The crystallite size, crystal structure, texture, and nanoparticle formation in MnO2 films have been influenced by Cu dopant. The maximum optical transmittance is found to be about 83%. The energy band gap associated with the allowed direct transition is found to increase from 3.82 to 3.96 eV with increasing Cu doping concentration up to 4 at%. Glucose sensitivity was measured by the four-probe technique. Notably, 4 at% Cu:MnO2 films have demonstrated the superior sensing ability of glucose of 29%.