Li2B4O7 glass exhibits photo-darkening suppression due to copper nanoparticles

We found evidence of reduction in photo-darkening due to the presence of copper nanoparticles (CNP) in lithium borate glasses doped with Ce 3+ and Tm 3+ . This phenomenon is attributed to plasmon effect produced by the CNP, which potentiates the effect of Ce 3+ in the process of avoiding photo-darkening in the glass samples. Glass samples were made by a melt-quenching technique. Fluorescence emission and absorption spectra present the characteristic peaks of Ce 3+ and Tm 3+ . Decompression of glass network has been observed due to changes in density and average boron–boron separation in all the samples. We have calculated the optical band gap which increase due to the increase of CNP. To investigate the glass photo-darkening transmittance of all the samples was measured after 1, 2, 3, 4, 5, 6, 18, 24, 90, 120 and 180 h exposed to radiation.