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A 19.9%-efficient ultrathin solar cell based on a 205-nm-thick GaAs absorber and a silver nanostructured back mirror

Abstract

Conventional photovoltaic devices are currently made from relatively thick semiconductor layers, ~150 µm for silicon and 2–4 µm for Cu(In,Ga)(S,Se)2, CdTe or III–V direct bandgap semiconductors. Ultrathin solar cells using 10 times thinner absorbers could lead to considerable savings in material and processing time. Theoretical models suggest that light trapping can compensate for the reduced single-pass absorption, but optical and electrical losses have greatly limited the performances of previous attempts. Here, we propose a strategy based on multi-resonant absorption in planar active layers, and we report a 205-nm-thick GaAs solar cell with a certified efficiency of 19.9%. It uses a nanostructured silver back mirror fabricated by soft nanoimprint lithography. Broadband light trapping is achieved with multiple overlapping resonances induced by the grating and identified as Fabry–Perot and guided-mode resonances. A comprehensive optical and electrical analysis of the complete solar cell architecture provides a pathway for further improvements and shows that 25% efficiency is a realistic short-term target.

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Fig. 1: Fabrication process for ultrathin GaAs solar cells with a nanostructured back mirror.
Fig. 2: Best ultrathin solar cell based on a 205-nm-thick GaAs absorber and a nanostructured Ag mirror.
Fig. 3: Optical analysis of the ultrathin GaAs solar cells.
Fig. 4: JV characteristics and loss analysis.

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Data availability

The data that support the plots within this paper and other findings of this study are available from the corresponding author upon reasonable request.

References

  1. Yoshikawa, K. et al. Silicon heterojunction solar cell with interdigitated back contacts for a photoconversion efficiency over 26%. Nat. Energy 2, 17032 (2017).

    Article  Google Scholar 

  2. Shockley, W. & Queisser, H. J. Detailed balance limit of efficiency of p–n junction solar cells. J. Appl. Phys. 32, 510–519 (1961).

    Article  Google Scholar 

  3. Kayes, B. M. et al. 27.6% conversion efficiency, a new record for single-junction solar cells under 1 sun illumination. In Proc. 2011 37th IEEE Photovoltaic Specialists Conference (PVSC) 000004–000008 (IEEE, 2011).

  4. Green, M. A. et al. Solar cell efficiency tables (Version 53). Prog. Photovolt. 27, 3–12 (2019).

    Article  Google Scholar 

  5. Green, M. A. Lambertian light trapping in textured solar cells and light-emitting diodes: analytical solutions. Prog. Photovolt. 10, 235–241 (2002).

    Article  Google Scholar 

  6. Yablonovitch, E. Statistical ray optics. J. Opt. Soc. Am. 72, 899–907 (1982).

    Article  Google Scholar 

  7. Hirst, L. C. et al. Intrinsic radiation tolerance of ultra-thin GaAs solar cells. Appl. Phys. Lett. 109, 033908 (2016).

    Article  Google Scholar 

  8. Brongersma, M. L., Cui, Y. & Fan, S. Light management for photovoltaics using high-index nanostructures. Nat. Mater. 13, 451–460 (2014).

    Article  Google Scholar 

  9. Collin, S. Nanostructure arrays in free-space: optical properties and applications. Rep. Prog. Phys. 77, 126402 (2014).

    Article  Google Scholar 

  10. Mokkapati, S. & Catchpole, K. R. Nanophotonic light trapping in solar cells. J. Appl. Phys. 112, 101101 (2012).

    Article  Google Scholar 

  11. Depauw, V. et al. Sunlight-thin nanophotonic monocrystalline silicon solar cells. Nano Futures 1, 021001 (2017).

    Article  Google Scholar 

  12. Branham, M. S. et al. 15.7% efficient 10-µm-thick crystalline silicon solar cells using periodic nanostructures. Adv. Mater. 27, 2182–2188 (2015).

    Article  Google Scholar 

  13. Gaucher, A. et al. Ultrathin epitaxial silicon solar cells with inverted nanopyramid arrays for efficient light trapping. Nano Lett. 16, 5358–5364 (2016).

    Article  Google Scholar 

  14. Wang, K. X., Yu, Z., Liu, V., Cui, Y. & Fan, S. Absorption enhancement in ultrathin crystalline silicon solar cells with antireflection and light-trapping nanocone gratings. Nano Lett. 12, 1616–1619 (2012).

    Article  Google Scholar 

  15. Kapur, P. et al. A manufacturable, non-plated, non-Ag metallization based 20.44% efficient, 243 cm2 area, back contacted solar cell on 40 μm thick mono-crystalline silicon. In Proc. 28th European Photovoltaic Solar Energy Conference and Exhibition 2228–2231 (WIP Renewable Energies, 2013).

  16. Cariou, R. et al. III–V-on-silicon solar cells reaching 33% photoconversion efficiency in two-terminal configuration. Nat. Energy 3, 326–333 (2018).

    Article  Google Scholar 

  17. Goffard, J. et al. Light trapping in ultrathin CIGS solar cells with nanostructured back mirrors. IEEE J. Photovolt. 7, 1433–1441 (2017).

    Article  Google Scholar 

  18. van Lare, C., Yin, G., Polman, A. & Schmid, M. Light coupling and trapping in ultrathin Cu(In,Ga)Se2 solar cells using dielectric scattering patterns. ACS Nano 9, 9603–9613 (2015).

    Article  Google Scholar 

  19. Söderström, K., Haug, F.-J., Escarré, J., Cubero, O. & Ballif, C. Photocurrent increase in n–i–p thin film silicon solar cells by guided mode excitation via grating coupler. Appl. Phys. Lett. 96, 213508 (2010).

    Article  Google Scholar 

  20. Zhu, J., Hsu, C.-M., Yu, Z., Fan, S. & Cui, Y. Nanodome solar cells with efficient light management and self-cleaning. Nano Lett. 10, 1979–1984 (2010).

    Article  Google Scholar 

  21. Liu, W. et al. Surface plasmon enhanced GaAs thin film solar cells. Sol. Energy Mater. Sol. Cells 95, 693–698 (2011).

    Article  Google Scholar 

  22. Nakayama, K., Tanabe, K. & Atwater, H. A. Plasmonic nanoparticle enhanced light absorption in GaAs solar cells. Appl. Phys. Lett. 93, 121904 (2008).

    Article  Google Scholar 

  23. Massiot, I. et al. Metal nanogrid for broadband multiresonant light-harvesting in ultrathin GaAs layers. ACS Photon. 1, 878–884 (2014).

    Article  Google Scholar 

  24. Atwater, H. A. & Polman, A. Plasmonics for improved photovoltaic devices. Nat. Mater. 9, 205–213 (2010).

    Article  Google Scholar 

  25. Vandamme, N. et al. Ultrathin GaAs solar cells with a silver back mirror. IEEE J. Photovolt. 5, 565–570 (2015).

    Article  Google Scholar 

  26. Miller, O. D., Yablonovitch, E. & Kurtz, S. R. Strong internal and external luminescence as solar cells approach the Shockley–Queisser limit. IEEE J. Photovolt. 2, 303–311 (2012).

    Article  Google Scholar 

  27. Steiner, M. A. et al. Optical enhancement of the open-circuit voltage in high quality GaAs solar cells. J. Appl. Phys. 113, 123109 (2013).

    Article  Google Scholar 

  28. Walker, A. W. et al. Impact of photon recycling on GaAs solar cell designs. IEEE J. Photovolt. 5, 1636–1645 (2015).

    Article  Google Scholar 

  29. Yang, W. et al. Ultra-thin GaAs single-junction solar cells integrated with a reflective back scattering layer. J. Appl. Phys. 115, 203105 (2014).

    Article  Google Scholar 

  30. Lee, S.-M. et al. High performance ultrathin GaAs solar cells enabled with heterogeneously integrated dielectric periodic nanostructures. ACS Nano 9, 10356–10365 (2015).

    Article  Google Scholar 

  31. Hugonin, J. P. & Lalanne, P. Reticolo (IOTA/CNRS, 2005); https://www.lp2n.institutoptique.fr/Membres-Services/Responsables-d-equipe/LALANNE-Philippe

  32. Lalanne, P. & Jurek, M. P. Computation of the near-field pattern with the coupled-wave method for transverse magnetic polarization. J. Mod. Opt. 45, 1357–1374 (1998).

    Article  Google Scholar 

  33. Lalanne, P. & Morris, G. M. Highly improved convergence of the coupled-wave method for TM polarization. J. Opt. Soc. Am. A 13, 779–784 (1996).

    Article  Google Scholar 

  34. Li, L. New formulation of the Fourier modal method for crossed surface-relief gratings. J. Opt. Soc. Am. A 14, 2758–2767 (1997).

    Article  Google Scholar 

  35. Yeh, P. Optical Waves in Layered Media (Wiley, 1988).

  36. Barugkin, C., Beck, F. J. & Catchpole, K. R. Diffuse reflectors for improving light management in solar cells: a review and outlook. J. Opt. 19, 014001 (2017).

    Article  Google Scholar 

  37. Fu, S. M. et al. Approaching conversion limit with all-dielectric solar cell reflectors. Opt. Express 23, A106–A117 (2015).

    Article  Google Scholar 

  38. Suckow, S. 2-3 diode fit. NanoHub (2014); https://nanohub.org/resources/14300

  39. Ochoa, M., Algora, C., Espinet-González, P. & García, I. 3-D modeling of perimeter recombination in GaAs diodes and its influence on concentrator solar cells. Sol. Energy Mater. Sol. Cells 120, 48–58 (2014).

    Article  Google Scholar 

  40. Sheldon, M. T., Eisler, C. N. & Atwater, H. A. GaAs passivation with trioctylphosphine sulfide for enhanced solar cell efficiency and durability. Adv. Energy Mater. 2, 339–344 (2012).

    Article  Google Scholar 

  41. Espinet-González, P. et al. Analysis of perimeter recombination in the subcells of GaInP/GaAs/Ge triple-junction solar cells. Prog. Photovolt. Res. Appl. 23, 874–882 (2015).

    Article  Google Scholar 

  42. Shen, T. C., Gao, G. B. & Morko, H. Recent developments in ohmic contacts for III–V compound semiconductors. J. Vac. Sci. Technol. B 10, 2113 (1992).

    Article  Google Scholar 

  43. Sandhu, S., Yu, Z. & Fan, S. Detailed balance analysis of nanophotonic solar cells. Opt. Express 21, 1209–1217 (2013).

    Article  Google Scholar 

  44. Xu, Y., Gong, T. & Munday, J. N. The generalized Shockley–Queisser limit for nanostructured solar cells. Sci. Rep. 5, 13536 (2015).

    Article  Google Scholar 

  45. Jain, S. C., McGregor, J. M. & Roulston, D. J. Band-gap narrowing in novel III–V semiconductors. J. Appl. Phys. 68, 3747–3749 (1990).

    Article  Google Scholar 

  46. Luo, C., Ni, X., Liu, L., Nomura, S. M. & Chen, Y. Degassing‐assisted patterning of cell culture surfaces. Biotechnol. Bioeng. 105, 854–859 (2010).

    Google Scholar 

  47. Dalstein, O. et al. Nanoimprinted, submicrometric, MOF-based 2D photonic structures: toward easy selective vapors sensing by a smartphone camera. Adv. Funct. Mater. 26, 81–90 (2016).

    Article  Google Scholar 

  48. Wang, L., Wei, J. & Su, Z. Fabrication of surfaces with extremely high contact angle hysteresis from polyelectrolyte multilayer. Langmuir 27, 15299–15304 (2011).

    Article  Google Scholar 

  49. Odom, T. W., Love, J. C., Wolfe, D. B., Paul, K. E. & Whitesides, G. M. Improved pattern transfer in soft lithography using composite stamps. Langmuir 18, 5314–5320 (2002).

    Article  Google Scholar 

  50. Cattoni, A., Cambril, E., Decanini, D., Faini, G. & Haghiri-Gosnet, A. M. Soft UV-NIL at 20 nm scale using flexible bi-layer stamp casted on HSQ master mold. Microelectron. Eng. 87, 1015–1018 (2010).

    Article  Google Scholar 

  51. Gao, L., Lemarchand, F. & Lequime, M. Exploitation of multiple incidences spectrometric measurements for thin film reverse engineering. Opt. Express 20, 15734–15751 (2012).

    Article  Google Scholar 

  52. Palik, E. D. Handbook of Optical Constants of Solids (Academic Press, 1997).

  53. Schubert M. & Woollam J. A. Isotropic dielectric functions of highly disordered AlxGa1−xInP (0 ≤ x ≤ 1) lattice matched to GaA. J. Appl. Phys. 86, 2025 (1999).

    Article  Google Scholar 

  54. Sturge, M. D. Optical absorption of gallium arsenide between 0.6 and 2.75 eV. Phys. Rev. 127, 768–773 (1962).

    Article  Google Scholar 

  55. Jiang, Y., Pillai, S. & Green, M. A. Realistic silver optical constants for plasmonics. Sci. Rep. 6, 30605 (2016).

    Article  Google Scholar 

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Acknowledgements

The authors acknowledge discussions with J.-F. Guillemoles, electromagnetic simulation support from P. Lalanne, J.-P. Hugonin and C. Sauvan and financial support through French ANR project NANOCELL (grant no. ANR-15-CE05-0026) and the French Renatech network.

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Contributions

H.-L.C. carried out most of the fabrication steps for the solar cell experiments at C2N and performed optical modelling and results analysis. A.W.W., O.H., D.L. and F.D. designed the optimized GaAs solar cell layer structure, D.L. wrote the recipe for epitaxy growth and G.S. evaluated the characterization results in the Fraunhofer ISE CalLab. H.-L.C., A.C., R.D.L., M.F., N.V., J.G., B.B., C.D. and N.B. developed and optimized the fabrication process. A.C. and M.F. specifically developed the nanoimprint process for TiO2 sol–gel films. N.V. contributed to the design and modelling of the devices. A.C. and S.C. developed the concept of ultrathin solar cells with a nanostructured back mirror and supervised the project. H.-L.C. and S.C. wrote the manuscript. All authors participated in the discussions and improvements of the manuscript.

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Correspondence to Stéphane Collin.

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Supplementary Figs. 1–18, Supplementary Notes 1–5, Supplementary Table 1, Supplementary refs. 1–8.

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Chen, HL., Cattoni, A., De Lépinau, R. et al. A 19.9%-efficient ultrathin solar cell based on a 205-nm-thick GaAs absorber and a silver nanostructured back mirror. Nat Energy 4, 761–767 (2019). https://doi.org/10.1038/s41560-019-0434-y

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