Ce³⁺-Yb³⁺, Tb³⁺-Yb³⁺ and Pr³⁺-Nd³⁺-Yb³⁺ mixed-doped TeO₂-ZnO-Na₂O glasses for enhancing the efficiency of silicon solar cells

In general, the sunlight wavelength absorbed by silicon solar cells is mainly concentrated in the range of 600-1100 nm. Although silicon solar cells can also absorb sunlight in the ultraviolet and visible regions with <600 nm, the utilization of light is very low. In addition, some high-energy photons in the ultraviolet and visible region can cause serious damage to silicon solar panels, reducing its useful lifetime and lowering its photoelectric conversion efficiency. Therefore, in order to make full use of the light in this range, we studied three-layer light-conversion glass doped with three groups of rare-earth ion to improve the utilization rate of light in silicon solar cells and prolong the lifetime. A series of zinc tellurate glasses (TeO2-ZnO-Na2O) doped with Ce3+-Yb3+, Tb3+-Yb3+ and Pr3+-Nd3+-Yb3+, respectively, were prepared by melting quenching method. The crystalline state and interior structure of the prepared glasses are characterized by using X-ray diffraction (XRD) spectra and Raman spectra. And the lowest phonon energy of these glasses is about 773 cm(-2). The photoluminescence properties of rare-earth ions doped in these glasses are studied. The results show that the near infrared emission (centered at 980 nm) of activator ion (Yb3+) is observed when the sensitizer ions (Ce3+, Tb3+, Pr3+ and Nd3+) are excited by using 430 nm, 355 nm and 488 nm ultraviolet and visible (UV-vis) photons, respectively. The down-conversion and down-shift energy transfer mechanisms between sensitizer ion and activator ion are discussed. Based on the above research, a triple-layer zinc tellurate glass sample doped with Ce3+-Yb3+/Tb3+-Yb3+/Pr3+-Nd3+-Yb3+ in a certain ratio is prepared. And the current density-voltage (J-V) curves of silicon solar cell covered with triple-layer zinc tellurate glass were tested. According to the data obtained from J-V curves, the relative efficiency (Delta eta) of Si solar cells covered with Ce3+-Yb3+/Tb3+-Yb3+/Pr3+-Nd3+-Yb3+ triple-layer zinc tellurate glass is increased by 2.37% compared with that of silicon solar cell covered with blank glass. So, the above results can show that the glass has important application values in improving the energy efficiency of silicon solar cells.