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.
1. Venkatesh, Y., R. S. Dubey, and B. Kumar, "Rapid and economic fabrication approach of dielectric reflectors for energy harvesting applications," Scientific Reports, Vol. 10, 15930-1-9, 2020.
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. doi:10.1016/j.optcom.2016.05.028
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. doi:10.1016/j.tsf.2013.09.047
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. doi:10.1364/JOSAB.411712
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. doi:10.1364/JOSAB.414777
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. doi:10.1039/C9RA10232A
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. doi:10.1364/OE.18.011763
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. doi:10.3390/en3121914
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. doi:10.1103/PhysRevB.85.115449
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. doi:10.1364/JOSAB.378946
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. doi:10.1364/JOSA.73.001105
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. doi:10.14355/jpo.2014.03.008
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. doi:10.1002/adma.201000488
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. doi:10.1002/adma.200900331
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. doi:10.1364/OL.32.002825
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. doi:10.1109/JPHOTOV.2012.2213583
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. doi:10.1364/OE.20.00A476
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. doi:10.1364/OE.20.00A177
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. doi:10.1103/PhysRevB.63.165103
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. doi:10.1063/1.3262954
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. doi:10.1364/AO.443307
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. doi:10.1021/acsenergylett.1c00568
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. doi:10.17586/2220-8054-2022-13-2-220-226
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. doi:10.1021/nl904057p
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. doi:10.1038/nature01937
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. doi:10.1364/OE.21.00A313
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. doi:10.1364/OE.21.004055