High-conductivity tellurium-based infrared transmitting glasses and their suitability for bio-optical detection

Many biological molecules carry a net surface charge and have the potential to be monitored in drinking water by electrodepositing them on an optical sensing element and measuring their spectroscopic fingerprints in the infrared (IR) spectral region. In this detection scheme, glasses with high conductivity and excellent IR transmitting property are essential. Therefore, it is necessary to develop suitable materials that combine these properties. In this paper, a series of high-conductivity IR transmitting glasses in Ge-As-Te and Ge-As-Te-Cu systems are reported. The conductivity, thermal stability, IR transmitting property, as well as chemical durability are studied. Their suitability for bio-optical detection applications is also evaluated. Some glasses in these two systems have relatively high conductivities (near 10^-4 (Ω·cm)^-1), and exhibit superior thermal stability, excellent IR transmitting property, as well as good chemical durability. The electro-deposition and spectroscopic tests of protein molecules indicate that these glasses are promising materials for bio-optical detection applications.