Compared to crystalline silicon solar cells, thin-film solar cells are inexpensive, but a weak absorption of sunlight at a longer wavelength is a significant issue. In this perspective, an efficient light trapping mechanism is needed to facilitate the light-guiding in enhancing light absorption. This paper presents a theoretical investigation of ultrathin amorphous silicon (a-Si) solar cells using the rigorous coupled-wave analysis (RCWA) method. We noticed broadband light absorption of the designed solar cell due to an efficient light trapping geometry. Our proposed design is composed of anti-reflection coating (ITO), an absorbing layer (a-Si), a back reflector (Ag-substrate), top-indium tin oxide (ITO), and bottom-silver (Ag) nanogratings. Using an Ag-back reflector with diffraction gratings demonstrated the improved diffraction and scattering of light, which enhanced light absorption within a 50 nm thick absorbing layer. Compared to the reference solar cell, the proposed ultrathin solar cell endorsed the enhanced photovoltaic conversion, i.e., 19% and 23%, corresponding to the transverse electric (TE) and magnetic (TM) polarization conditions. Furthermore, we explore the investigations of light absorption, current density, field distributions, reflection, transmission, and parasitic losses for the optimal design of ultrathin film (a-Si) solar cells.
2. Saravanan, S. and R. S. Dubey, "Study of ultrathin-film amorphous silicon solar cell performance using photonic and plasmonic nanostructure," International Journal of Energy Research, 1-9, 2021.
3. Saravanan, S. and R. S. Dubey, "Optical absorption enhancement in 40 nm ultrathin film silicon solar cells assisted by photonic and plasmonic modes," Optics Communications, Vol. 377, 65-69, 2016.
4. Sidharthan, R. and V. M. Murukeshan, "Improved light absorption in thin film solar cell using combination of gap modes and grating back reflector," Thin Solid Films, 581-584, 2013.
5. Olaimat, M. M., L. Yousefi, and O. M. Ramahi, "Using plasmonics and nanoparticles to enhance the efficiency of solar cells: Review of latest technologies," Journal of the Optical Society of America B, Vol. 38, No. 2, 638-651, 2021.
6. Aly, A. M. A., M. Hussein, A. Yahia, M. F. O. Hameed, and S. S. A. Obayya, "Highly efficient SiO2 trapezoidal grating-based thin-film solar cell," Journal of the Optical Society of America B, Vol. 38, No. 3, 922-931, 2021.
7. Du, J., Y. An, C. Zhu, X. Li, and D. Ma, "Photonic design and electrical evaluation of dual-functional solar cells for energy conversion and display application," Nanoscale Research Letters, Vol. 14, 1-9, 2019.
8. Subhan, F. E., A. D. Khan, F. E. Hilal, A. D. Khan, S. D. Khan, R. Ullah, M. Imran, and M. Noman, "Efficient broadband light absorption in thin-film a-Si solar cell based on double sided hybrid bi-metallic nanogratings," RSC Advances, Vol. 10, 11836-11842, 2020.
9. Amalathas, A. P. and M. M. Alkaisi, "Nanostructures for light trapping in thin film solar cells," Micromachines, Vol. 10, No. 619, 1-18, 2019.
10. Shi, Y., X. Wang, W. Liu, T. Yang, and F. Yang, "Hybrid light trapping structures in thin film silicon solar cells," Journal of Optics, Vol. 16, 075706-1-7, 2014.
11. Chao, C. C., C. M. Wang, and J. Y. Chang, "Spatial distribution of absorption in plasmonic thin film solar cells," Optics Express, Vol. 18, No. 11, 11763-11771, 2010.
12. Duhring, M. B., N. A. Mortensen, and O. Sigmund, "Plasmonic versus dielectric enhancement in thin film solar cells," Applied Physics Letters, Vol. 100, 211914-1-4, 2012.
13. Lai, F. I., J. F. Yang, Y. C. Hsu, and S. Y. Kuo, "Improvement of amorphous silicon thin-film photovoltaic cells with zinc oxide nanorods," Crystals, Vol. 10, 1124-1-10, 2020.
14. Mutitu, J. G., S. Shi, A. Barnett, and D. W. Prather, "Hybrid dielectric-metallic back reflector for amorphous silicon solar cells," Energies, Vol. 3, 1914-1933, 2010.
15. Abass, A., K. Q. Le, A. Alu, M. Burgelman, and B. Maes, "Dual interface gratings for broadband absorption enhancement in thin film solar cells," Physics Review B, Vol. 85, 115449-1-7, 2012.
16. Kumawat, U. K., K. Kumar, S. Mishra, and A. Dhawan, "Plasmonic enhanced microcrystalline silicon solar cells," Journal of the Optical Society of America B, Vol. 37, No. 2, 495-504, 2020.
17. Moharam, M. G. and T. K. Gaylord, "Three-dimensional vector coupled-wave analysis of planar-grating diffraction," Journal of the Optical Society of America, Vol. 73, No. 9, 1105, 1983.
18. Guo, X., J. Liu, and S. Zhang, "Design of light trapping structures for ultrathin solar cells," Photonics and Optoelectronics (P&O), Vol. 3, 66-69, 2014.
19. Ferry, V. E., J. N. Munday, and H. A. Atwater, "Design considerations for plasmonic photovoltaics," Advanced Materials (Deerfield Beach Fla.), Vol. 22, No. 43, 4794-4808, 2010.
20. Pala, R. A., J. White, E. Barnard, J. Liu, and M. L. Brongersma, "Design of plasmonic thin-film solar cells with broadband absorption enhancements," Advanced Materials (Deerfield Beach Fla.), Vol. 21, No. 34, 3504-3509, 2009.
21. Panoiu, N. C., R. M. Osgood, and Jr., "Enhanced optical absorption for photovoltaics via excitation of waveguide and plasmon-polariton modes," Optics Letters, Vol. 32, No. 19, 2825-2827, 2007.
22. Pahud, C., V. Savu, M. Klein, O. Vazquez-Mena, F.-J. Haug, J. Brugger, and C. Ballif, "Stencil-nanopatterned back reflectors for thin-film amorphous silicon n-i-p solar cells," IEEE Journal of Photovoltaics, Vol. 3, No. 1, 22-26, 2013.
23. Zilio, P., D. Sammito, G. Zacco, M. Mazzeo, G. Gigli, and F. Romanato, "Light absorption enhancement in heterostructure organic solar cells through the integration of 1-D plasmonic gratings," Optics Express, Vol. 20, No. S4, A476-A488, 2012.
24. Dunbar, R. B., T. P. Fadler, and L. Schmidt-Mende, "Highly absorbing solar cells --- A survey of plasmonic nanostructures," Optics Express, Vol. 20, No. S2, A177-A189, 2012.
25. Lee, S. and S. Kim, "Optical absorption characteristic in thin a-Si film embedded between an ultrathin metal grating and a metal reflector," IEEE Photonics, Vol. 5, No. 5, 2013.
26. Villa, F., T. Lopez-Rios, and L. E. Regalado, "Electromagnetic modes in metal-insulator-metal structures," Physics Review B, Condensed Matter, Vol. 63, No. 16, 165103-1-165103-4, 2001.
27. Vuong, L. T., G. Kozyreff, R. Betancur, and J. Martorell, "Cavity-controlled radiative recombination of excitons in thin-film solar cells," Applied Physics Letters, Vol. 95, No. 23, 233106-1-233106-3, 2009.
28. Chen, K., N. Zheng, S. Wu, J. He, Y. Yu, and H. Zheng, "Effective light trapping in c-Si thin-film solar cells with a dual-layer split grating," Appl. Opt., Vol. 60, No. 33, 10312-10321, 2021.
29. Tennyson, E. M., K. Frohna, W. K. Drake, F. Sahli, T. C.-J. Yang, F. Fu, J. Werner, C. Chosy, A. R. Bowman, T. A. S. Doherty, Q. Jeangros, C. Ballif, and S. D. Stranks, "Multimodel microscale imaging of textured perovskite-silicon tandem solar cells," ACS Energy Letters, Vol. 6, No. 6, 2293-2304, 2021.
30. Dubey, R. S. and S. Saravanan, "Impact of distributed Bragg's reflectors and nanogratings in thin film silicon solar cells," Nanosyst: Phys. Chem. Math., Vol. 13, No. 2, 223-229, 2022.
31. Wang, W., S. Wu, K. Reinhardt, Y. Lu, and S. Chen, "Broadband light absorption enhancement in thin-film silicon solar cells," Nano Letters, Vol. 10, No. 6, 2012-2018, 2010.
32. Khaleque, T. and R. Magnusson, "Light management through guided-mode resonances in thin-film silicon solar cells," Journal of Nanophotonics, Vol. 8, 083995-1-083995-13, 2014.
33. Barnes, W. L., A. Dereux, and T. W. Ebbesen, "Surface plasmon subwavelength optics," Nature, Vol. 424, No. 6950, 824-830, 2003.
34. Zhu, L.-H., M.-R. Shao, R.-W. Peng, R.-H. Fan, X.-R. Huang, and M. Wang, "Broadband absorption and efficiency enhancement of an ultra-thin silicon solar cell with a plasmonic fractal," Optics Express, Vol. 21, No. S3, A313-A323, 2013.
35. Lee, S., S. J. In, D. R. Mason, and N. Park, "Incorporation of nanovoids into metallic gratings for broadband plasmonic organic solar cells," Optics Express, Vol. 21, No. 4, 4055-4060, 2013.