Yb3+-doped GeS2-Ga2S3-CsCl glass with broad and adjustable absorption/excitation band for near-infrared luminescence
Résumé
The luminescent property of Yb3+ ions in GeS2-Ga2S3-CsCl glasses with different CsCl contents has been studied. All the samples demonstrate a broad excitation band in the UV or/and visible range, depending on the composition, which is attributed to the charge transfer of the Yb3+-S2−/Cl− couple. The width of the excitation/absorption band can be as large as 150 nm. Moreover, with the increase of CsCl content, the peak position of the band can be continuously adjusted from 458 to 380 nm, due to the increase of the local average electronegativity around Yb3+ ions. The broad and adjustable excitation band makes the Yb3+-doped GeS2-Ga2S3-CsCl glass interesting for modifying the solar spectrum by absorbing strongly in the UV/blue region for emission around 1 μm. This kind of material is the key to adapting the solar spectrum to the response of silicon photovoltaic solar cells.