High-performance photodetection of UV-visible-NIR by Ag-Mn2O3 heterojunctions

Ag-Mn2O3 was evaluated as a new photosensing material to detect UV-visible-NIR radiation, and the results were compared to those obtained from single-phase Mn2O3. The materials were prepared by the coprecipitation method, from metal nitrates, and later calcined at 500 degrees C, in air. The morphology of Ag-Mn2O3 consists of cuboid-shaped microparticles, with silver nanowires randomly attached to its surface. The photoresponse profiles show uniform and reproducible variations in electrical current caused by light exposure. However, for Ag-Mn2O3 they were up to 46 times higher than those measured in Mn2O3. This improvement can be attributed to the decrease in the bandgap energy of Ag-Mn2O3, associated with the formation of metal-semiconductor heterojunctions and the fact that silver has a lower work function and a greater number of free electrons.