Light trapping mechanism of hemisphere cone arrays for silicon solar cells. (15th March 2018)

• Record Type: Journal Article
• Authors: Chen, Le; Wang, Qingkang; Chen, Wen; Liu, Daiming; Zhao, Zhouxing; Wang, Danyan
• Is Part Of: Solar energy. Volume 163(2018)
• Page Start: 519
• Page End: 525
• Publication Date: 2018-03-15
• Subjects: Light trapping mechanism -- Hemisphere cone arrays (HCAs) -- Anti-reflection -- Optical path length; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2017.10.004
• Languages: English
• ISSNs: 0038-092X

Abstract

Graphical abstract: This study shows that the hemisphere cone arrays (HCAs) structure can reduce surface reflectance by ∼60% compared with flat structure, and can make ∼43% unabsorbed light return to the absorbing layer of solar cells again. Thus, It has excellent anti-reflection ability, which can effectively reduce the total reflectivity of a solar cell by 30%. To verify the theoretical calculation results, a flat and a square hemispherical cone arrays PDMS thin films were prepared, and the reflectivities of a silicon wafer covered the flat and the HCAs PDMS thin films are measured. Figure (a) shows the photograph of the HCAs PDMS thin film and Figure (b) shows the diffration pattern of a laser beam (500nm) passing through the PDMS thin film. Figure (c) and the inset show the SEM images of HCAs in the PDMS thin film. Figure (d) provides a graphic explanation of the light reflectivity characteristics of a Si wafer covered a HCAs PDMS thin film and compares it with a flat PDMS thin film. Figure (e) shows the theoretical and experimental reflectivity of a Si wafer separately covered with the flat and the HCAs PDMS thin films at surface-normal incident angle in the wavelength of 300–1100 nm. Highlights: The light trapping mechanism of the HCAs in silicon solar cells is studied. HCAs can reduce reflectance by ~60% and make ~43% light return to absorbing layer. Total optical path length of the Si solar cell with the HCAs increases from 2 ω to 4 ω . A square HCAs PDMS thin films were prepared by a micro/nano-processing method. Abstract: Hemisphere cone arrays (HCAs) is a popular light trapping structure in silicon solar cells. However, the light trapping mechanism research of that in solar cells is lacking. In this paper, the light trapping mechanism of the HCAs in silicon solar cells is studied by combination of numerical analysis and geometrical optics simulation. The results show that the HCAs structure can reduce surface reflectance by ∼60% compared with flat structure by multiple injections of the incident light. At the same time, the HCAs can make ∼43% unabsorbed light return to the absorbing layer of solar cells again. To verify the theoretical calculation results, a flat and a square hemispherical cone arrays PDMS thin films are prepared by a micro/nano-processing method, and the reflectivities of a silicon wafer covered the flat and the HCAs PDMS thin films were measured. The experimental measured results are basically consistent with the theoretical calculation results. The numerical calculation results also show that the total optical path length of the thin film Si solar cell covered with the HCAs structure increases from 2 ω to 4 ω .