Enhancement of Light Trapping by Aluminum Back Reflector on Stainless Steel Substrate for Amorphous Silicon Thin-Film Solar Cell

• Main Authors: Yang-Jyun Ciou, 邱揚峻
• Other Authors: Herchang Ay
• Format: Others
• Language: zh-TW
• Published: 101
• Online Access: http://ndltd.ncl.edu.tw/handle/2f6s53

碩士 === 國立高雄應用科技大學 === 應用工程科學研究所 === 100 === A variety of thin film solar cells have been commercialize or low-cost of solar electricity in recent years. The flexible with lightweight of thin metal material and polymer substrates have seeking the most potential in the future of photovoltaic technology. Amorphous silicon (a-si:H) solar cells has a lower conversion efficiency, and absorption in the wavelength range between 400 nm and 700 nm. Nowadays, there are various light trapping structures have been applied to enhance light trapping in thin-film Si solar cells, and this is a key role in increasing the conversion efficiency. This research will focus on increase the conversion efficiency for amorphous silicon solar cells which an n–i–p configuration were placed on stainless steel substrates. The process is using dc magnetron sputtering follow by the AZO and Al films were prepared on the stainless steel substrates. , and examined the Optical properties (reflectance and scattered light reflectance) of the back reflectors in order to enhance the amorphous silicon solar cells conversion efficiency. According to the results, The Al films were deposited by varying a sputtering power at 500W 1000W and 1500W, the films grain size were 37.85nm、44.70nm and 54.58nm；the surface roughness were 13.55nm、14.62nm and 16.18nm. In the amorphous silicon solar cells effect the absorption wavelength range between 400 nm and 700 nm. , The average reflectance were 74.59%、77.03% and 79.19% and the average scattered light reflectance were 7.42%、11.64% and 17.39%. From the microscope, sputtering power increased, scanning electron microscopy images can showed a dense grain structure. After the 100-nm thick AZO films sputtering power 500W were overlap on the complete Al surfaces, the grain size of the Al/AZO layers were 39.04nm、56.01nm and 62.88nm；The surface roughness were 13.73nm、17.43nm and 19.29nm；the average reflectance were 72.07%、72.27% and 72.72%；the average scattered light reflectance were 14.02%、16.21% and 19%. In addition, the surface morphologies of the back reflectors were modified by changing the sputtering power of the Al films to improve the light-scattering properties on the back reflectors. The research had accomplished the comparison between the back reflectors and non-back reflectors surface features. Showed the conversion efficiency of the solar cells will increase from 3.46% to 4.52%. The Jsc value will also increase from 7.48 mA/cm2, to 11.12 mA/cm2. The results indicated the increasing the rough surface of the back reflectors will affect the increasing roughness directly. To enhanced light scattering from the back reflectors will cause the performance of the solar cells mainly in terms of the short-circuit current density (Jsc). Thus, amorphous silicon solar cells conversion efficiency can be improved.