Compositional dependence of broadband near-infrared downconversion and upconversion of Yb3+-doped multi-component glasses

Abstract

Yb3+ single-doped glasses show a strong excitation band in the 300–400 nm region, and efficiently emit photons with wavelengths of 920–1150 nm, and have potential applications in solar cells operating in an extraterrestrial situation. In this work, we systematically study the broadband near-infrared downconversion and upconversion of Yb3+-doped silicate, germanate, phosphate, tellurite and tungsten tellurite glasses. All samples show a broad excitation band in the 300–400 nm range, which is attributed to the charge transfer of the Yb3+–O2− couple. The position of the charge transfer band (CTB) shifts from 300 nm to longer wavelengths around 350 nm when the length of the R–O(Si, P, Ge, Te) increases. The longer R–O gives rise to a smaller central void for Yb3+, thus resulting in a small proportion of Yb3+ ions, thus leading to the blue-shift of the CTB. A smaller proportion of Yb3+ in silicate glasses causes in the strongest upconversion emission at 500 nm.