Preparation of quaternary boro-phosphate multifunctional glasses and their structural, optical, switching and antibacterial properties

Abstract In this paper, the glass composition of (50-x)P 2 O 5 -xB 2 O 3 -30CuO-20Li 2 O (x = 0, 5, 10, 15, and 20 mol%) was prepared and the effect of P 2 O 5 substitution by B 2 O 3 on their structural, optical, switching, and antibacterial characteristics was studied. FT-IR spectra showed that an increase in the B 2 O 3 content leads to gradual erosion of the phosphate characteristic bonds, and the emergence of borate-related ones by creating new linkages between phosphate chains through P–O–B bonds and formation of highly cross-linked P 3 -O-B 4 linkages. The incorporation of boron up to 20 mol%, also leads to an overall increase in glass transition temperature together with a decrease in the molar volume which both, implied improvement of glass stability. Optical studies revealed that all glasses are almost transparent in the UV–Vis region with high band gap energy about 3.83 eV, which experiences a red-shift with increase in the B 2 O 3 concentration to 15 mol%. By calculating the wavelength-dependent optical parameters, however, it was found that the present glass composition with highest concentration of B 2 O 3 shows refractive index near one and very negligible extinction coefficient (and imaginary optical dielectric function) at the visible region. These results support the great potential of the mentioned glass composition as a window layer. The analysis of the high electric field measurements demonstrated a wide range reduction in switching threshold voltage as the B 2 O 3 content increases. This hints at their potential application as electrical-induced sensors. The antibacterial activity of x = 0 and x = 5 glass compositions has been examined by zone of inhibition measurements and it was found that they have potential applications as antibacterial agent.