Novel UV photoluminescence from spark-processed porous copper

The intent of this paper is to report the preparation of porous copper by using spark discharge in ambient air and its luminescence properties. The photoluminescence characteristics of spark-processed copper have been studied at various temperatures. Properties of spark-processed copper were further studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FT-IR). In addition to the luminescence peaks of 435 nm (2.85 eV) and 533 nm (2.39 eV), which are also observed from sintered CuO, the photoluminescence studies of spark-processed copper revealed a sharp emission band in the UV (3.3 eV). This novel UV luminescence band is further separated into three peaks centered at 3.38, 3.33, and 3.25 eV below 100 K. FT-IR studies of spark-processed Cu mainly demonstrated characteristic vibration modes stemming from CuO. Further, a formation of CuO is evidenced by the XRD studies of spark-processed Cu. The luminescence properties of spark-processed Cu are discussed based on the experimental results.