| Summary: | 碩士 === 國立臺北科技大學 === 光電工程系 === 107 === The way to improve the loss of silicon solar cell due to the absorbed spectral limitation of silicon by using spectral conversion of luminescent down-shifting (LDS) and up conversion (UC) had been studied. LDS can absorb high-energy photons of short-wavelength and release lower-energy photons of long-wavelength, and UC work in reverse. In the present study, the efficiency of LDS improved by using the metal nanoparticles effect of local surface plasmon resonance (LSPR) be focus on.
In this paper, we combine three-species LDS phosphor on silicon solar cells at first. Then, we investigate phosphor LDS effect and silver nanoparticles (Ag NPs) LSPR effect on silicon solar cells. Final, scanning electron microscope image, absorbance, Photoluminescence, optical reflectance, external quantum efficiency, dark current-voltage, and photovoltaic current-voltage measurements, are used to compare solar cells with LDS effects and LSPR effects, respectively.
We design the experiment of this study to construct the spectral conversion layer on the surface of silicon solar cells：(1) planar silicon solar cells based on effect of LDS of Eu-doped phosphors, (2) planar silicon solar cells based on combined effect of LDS of Eu-doped phosphors and LSPR of Ag NPs.
Part one, we firstly deposited TiO2 antireflective coatings on silicon solar cells. Secondly, we mix three-species (512 & 550 & 610 nm wavelengths) of phosphors with SiO2 solution and subsequently deposited on the cell using spin coating technique. To achieve the best results, we found that combining three-species of phosphor with concentration of 3 wt% and species ratio of 1: 2: 3 is a good choice. The conversion efficiency enhancement of 39.55% (from 10.07% to 14.06%) can be obtained.
Part two, we first deposited a SiO2 space layer and subsequently a deposited silver film on silicon solar cells using E-beam evaporation. After annealing, we can get different diameter Ag NPs. Final, the conversion layer combination of different diameters Ag NPs with 512 or 550 or 610 nm wavelengths of phosphors was proposed. In this topic the conversion efficiency of solar cells with effect of LDS, PL enhancement, PL quenching were discussed. In results, we found that 3 nm Ag NPs combining 512 nm phosphors conversion layer to enhance the efficiency enhancement up to 26.02% (from 10.23% to 12.89%) was obtained.
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