NNT-abstract

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Roll-to-Roll prepared flexible antireflection film with
microstructure for photovoltaic applications
Min Wang, Pengsha Ma, Dongdong Li,
Shanghai Advanced Research Institute, Chinese Academy of Sciences
E-mail: [email protected]
Optical management in photovoltaic devices is crucial for improving their efficiency. Inspired
by the structure of moth eye, anti-reflection (AR) films with gradient of effective refractive
index have been achieved by one-dimensional arrayed nanostructures [1-4]. However, the
nanoscaled structures are encountering poor mechanical strength, which cannot meet the
challenge of harsh condition outside.
Herein, we report a flexible AR film with microscaled structure through roll-to-roll fabrication
process (Figure 1a), which delivered enhanced light harvesting capability for solar cells with
stronger mechanical strength. The AR film was attached onto the surface of a triple junction
thin film silicon solar cell (a-Si) by a lamination process (Figure 1b). A broadband decreased
reflectance was achieved compared to the one without AR film (Figure 2a), which is further
verified by the quantum efficiency (QE) and I-V measurements (Figure 2b and 2c). The
significance of AR film is positively correlated with the increased incident angle. As the
incident angle increased, the η for both cells with and without AR film was reduced, while the
relative improvement of η gradually increases from 3.7% to 11.5% when the incident angle
increases from 0°to 60°(Figure 2d).
In brief, the proposed AR films apparently improved the efficiency of solar cells, with the
advantages of higher mechanical strength and easier fabrication process. This possesses great
potential for large scale deployment on photovoltaic panels with both flexible and rigid
substrates.
References
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Nano Lett., 10 (2010) 3823-3827.
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Nanopillar/Nanowell Arrays for Three-Dimensional Thin-Film Photovoltaic Applications, ACS nano, 7 (2013)
2725-2732.
Figure 1. Schematics of AR film fabrication with roll-to-roll process and AR film attached on solar
cell. α (located in yoz plane) and β (located in xoz plane), represent the incident light angle.
Figure 2. (a) Reflectance spectra of a-Si solar cell with and without AR film. (b) QE measurement of
a-Si solar cell with and without AR film, which contains three overlapped cells, top cell, middle cell,
bottom cell. (c) J-V measurements of a-Si solar cell with and without AR film at 0 and 60 degrees of
incident light (α). (d) η of a-Si solar cell with and without AR film obtained at different angles (α),
together with the angular-dependent relative improvement of η.
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