Down-conversion glass substrate as well as preparation method thereof and application in CdTe solar battery

The invention discloses a down-conversion glass substrate. The down-conversion glass substrate comprises bismuth ions Bi and thulium ions Tm . The down-conversion glass substrate consists of the following oxides at the following molar ratio: 65 to 85 percent of germanium dioxide (GeO2)d, 0 to 15 percent of magnesium oxide (MgO), 0 to 15 percent of aluminum oxide (Al2O3), 0 to 2 percent of bismuth trioxide (Bi2O3) and 0 to 3 percent of thulium oxide (Tm2O3). The invention also discloses a preparation method and an application of the down-conversion glass substrate. The down-conversion glass substrate can absorb the light of 450nm to 750nm so as to emit the light of 800nm, so that the CdTe solar battery can be well responded. The down-conversion glass substrate is applied to the CdTe solar battery and can substitute a down-conversion layer and a glass substrate of the existing CdTe solar battery, the conversion efficiency of the solar battery can be improved, and the packaging efficiency can be increased.