| Summary: | 碩士 === 國立臺北科技大學 === 光電工程系 === 106 === This paper study combination of three speciess of europium doped silicate phosphor with excitation wavelength (512, 550, 610 nm) on silicon solar cells to enhance photovoltaic performance. The phosphor powder was firstly mixed with a silicate solution and then deposited on the surface of the cell as a spectral conversion layer using spin-on film technique. Since the single-crystal silicon solar cell has surface recombination loss and high reflectivity in the short wavelength region (300-450 nm), the conversion efficiency in the short wavelength region was limited. The role of europium-doped silicate phosphor in the spectral conversion layer is absorbed high-energy photons of short-wavelength and released lower-energy photons of long-wavelength (Named as luminescent down-shifting, LDS), which can enhance the contribution of the short-wavelength spectrum to silicon solar cells. On the other hand, the phosphor particles can scatter the incident light and increase the path of the light in the active material. In addition, the proposed spectral conversion layer exhibit good antireflection. The above comprehensive contribution can effectively improve the photocurrent density (Jph) and conversion efficiency (η) of the solar cell.
The experimental scheme of this study to construct the spectral conversion layer on the surface of silicon solar cells is: (1) using single-species of phosphors (emission wavelength of phosphor : 512 nm, 550 nm, 610 nm); (2) combining two-species phosphor (512 & 550 nm, 550 & 610 nm, 512 & 610 nm); (3) combining three-species of phosphor (512 & 550 & 610 nm) and adjust the ratio of the three species phosphors.
The obtained results are: (1) for single-species of phosphor (610 nm), the conversion efficiency improvement of 19.63% (from 9.107% to 10.89%), (2) in case of combining two-species of phosphor (512 & 610 nm), the conversion efficiency enhancement of 21.72% (from 9.124% to 11.10%), (3) in combining three-species of phosphor (512 & 550 & 610 nm) with concentration of 6 wt% and species ratio of 1: 2: 3, the conversion efficiency enhancement of 27.20% (from 9.135% to 11.62%).
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