Influence of Laser Texturing on the Formation of Multiscale Textures for Broadband Light Absorption Enhancement in a-Si Thin film for Solar cells.
9 July 2018
A light-trapping scheme, such as the textures, is required for the efficient collection of light in thin film solar cells to achieve high light conversion efficiencies. Light trapping is important for thin film solar cells where a single light-pass through the absorber is not sufficient to capture the weakly absorbed red and near-infrared photons.
The amount of light absorbed depends on the optical path length and the absorption coefficient. In the present work, influence of laser fluence and different ambience on surface texturing is studied to improve the light-trapping characteristics. Laser texturing with a nanosecond pulsed Nd3+:YAG laser in air and water is used to create surface textures in a-Si thin films that enhances light-trapping along with simultaneous crystallization and hydrogenation.
The light-trapping characteristics of textures are analyzed by optical reflectance measurements. The reflectance values across the whole spectra reduced by 20% to 35% compared to untreated sample indicating an improvement in light trapping via multiple reflections due to the textured surface. Theoretical simulation shows the increase in absorption in the long wavelength region with the multiscale textures compared to uniform textures.
Vidhya, Y.E.B. and Vasa, N.J., Influence of Laser Texturing on the Formation of Multiscale Textures for Broadband Light Absorption Enhancement in a-Si Thin film for Solar cells. Department of Engineering Design, Indian Institute of Technology, 2018.
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