High-concentration planar microtracking photovoltaic system exceeding 30% efficiency

  • Nature Energy 2, Article number: 17113 (2017)
  • doi:10.1038/nenergy.2017.113
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Prospects for concentrating photovoltaic (CPV) power are growing as the market increasingly values high power conversion efficiency to leverage now-dominant balance of system and soft costs. This trend is particularly acute for rooftop photovoltaic power, where delivering the high efficiency of traditional CPV in the form factor of a standard rooftop photovoltaic panel could be transformative. Here, we demonstrate a fully automated planar microtracking CPV system <2 cm thick that operates at fixed tilt with a microscale triple-junction solar cell at >660× concentration ratio over a 140 full field of view. In outdoor testing over the course of two sunny days, the system operates automatically from sunrise to sunset, outperforming a 17%-efficient commercial silicon solar cell by generating >50% more energy per unit area per day in a direct head-to-head competition. These results support the technical feasibility of planar microtracking CPV to deliver a step change in the efficiency of rooftop solar panels at a commercially relevant concentration ratio.

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  1. 1.

    Commercial progress and challenges for photovoltaics. Nat. Energy 1, 15015 (2016).

  2. 2.

    Research opportunities to advance solar energy utilization. Science 351, 353 (2016).

  3. 3.

    et al. On the Path to SunShot: The Role of Advancements in Solar Photovoltaic Efficiency, Reliability, and Costs Tech. Rep. NREL/TP-6A20-65872 (2016).

  4. 4.

    , ,  & Current Status of Concentrator Photovoltaic (CPV) Technology Tech. Rep. NREL/TP-5J00-65130 (2015).

  5. 5.

     & Handbook of Concentrator Photovoltaic Technology Vol. 53 (John Wiley, 2016).

  6. 6.

    ,  & Planar micro-optic solar concentrator. Opt. Express 18, 1122–1133 (2010).

  7. 7.

    , , ,  & Two-axis solar tracking accomplished through small lateral translations. Appl. Opt. 51, 6117–6124 (2012).

  8. 8.

    ,  & Nominally stationary high-concentration solar optics by gradient-index lenses. Opt. Express 19, 2325–2334 (2011).

  9. 9.

    ,  & Tracking integration in concentrating photovoltaics using laterally moving optics. Opt. Express 19, A207–A218 (2011).

  10. 10.

    ,  & Thermal phase change actuator for self-tracking solar concentration. Opt. Express 20, A964 (2012).

  11. 11.

    ,  & Light induced fluidic waveguide coupling. Opt. Express 20, A924 (2012).

  12. 12.

    ,  & Tailored free-form optics with movement to integrate tracking in concentrating photovoltaics. Opt. Express 21, A401–A411 (2013).

  13. 13.

    ,  & Proof of principle demonstration of a self-tracking concentrator. Opt. Express 22, A498 (2014).

  14. 14.

    , , ,  & Wide-angle planar microtracking for quasi-static microcell concentrating photovoltaics. Nat. Commun. 6, 6223 (2015).

  15. 15.

    ,  & Tracking-integrated systems for concentrating photovoltaics. Nat. Energy 1, 16018 (2016).

  16. 16.

    ,  & Fundamental and practical limits of planar tracking solar concentrators. Opt. Express 24, 1635–1646 (2016).

  17. 17.

    ,  & Durable broadband graded-index fluoropolymer antireflection coatings for plastic optics. Optica 4, 239–242 (2017).

  18. 18.

    et al. Solar cell generations over 40% efficiency. Prog. Photovolt. Res. Appl. 20, 801–815 (2012).

  19. 19.

    et al. Printing-based assembly of quadruple-junction four-terminal microscale solar cells and their use in high-efficiency modules. Nat. Mater. 13, 593–598 (2014).

  20. 20.

    , ,  & Six-junction (6J) microscale concentrating photovoltaics (CPV) for space applications. In 2016 IEEE 43rd Photovolt. Spec. Conf. 3415–3420 (IEEE, 2016).

  21. 21.

     & Handbook of Photovoltaic Science and Engineering Ch. 10 (John Wiley, 2011).

  22. 22.

    ESRL Global Monitoring Division—Global Radiation Group (NOAA, accessed 8 November 2016);

  23. 23.

     & Physics of Solar Cells: From Basic Principles to Advanced Concepts (Wiley, 2016).

  24. 24.

    et al. Ultrahigh efficiency HCPV modules and systems. IEEE J. Photovolt. 6, 1360–1365 (2016).

  25. 25.

     & Durability of Fresnel lenses: a review specific to the concentrating photovoltaic application. Sol. Energy Mater. Sol. Cells 95, 2037–2068 (2011).

  26. 26.

    et al. An end of service life assessment of PMMA lenses from veteran concentrator photovoltaic systems. Sol. Energy Mater. Sol. Cells 167, 7–21 (2017).

  27. 27.

     & Solar Position Algorithm for Solar Radiation Applications (Revised) NREL/Tp-560-34302 (2008).

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This work was funded in part by the Advanced Research Projects Agency-Energy (ARPA-E) MOSAIC program, US Department of Energy, under Award No. DE-AR0000626 and by the National Science Foundation under Grant No. CBET-1508968. J.H. and R.G.N. were supported as part of the Department of Energy ‘Light-Material Interactions in Energy Conversion Energy Frontier Research Center’ under grant DE-SC0001293.

Author information

Author notes

    • Jared S. Price
    • , Alex J. Grede
    •  & Baomin Wang

    These authors contributed equally to this work.


  1. Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA

    • Jared S. Price
    • , Alex J. Grede
    • , Baomin Wang
    • , Michael V. Lipski
    •  & Noel C. Giebink
  2. Semprius Inc., 4915 Prospectus Drive, Suite C, Durham, North Carolina 27713, USA

    • Brent Fisher
    •  & Scott Burroughs
  3. Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA

    • Kyu-Tae Lee
    •  & John A. Rogers
  4. Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA

    • Junwen He
    •  & Ralph G. Nuzzo
  5. Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA

    • Gregory S. Brulo
    • , Xiaokun Ma
    •  & Christopher D. Rahn


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J.S.P. designed and characterized the optics, designed the test jig for the CPV system, and performed the thermal simulations. A.J.G. wrote the outdoor testing software, and A.J.G. and M.V.L. wrote the tracking algorithm. B.W. designed and deposited all of the optical coatings and simulated the manufacturing and thermal tolerances of the system. Outdoor testing was carried out by all of the aforementioned authors. B.F. and S.B. supplied the 3J μPV cells for field testing, while K.-T.L., J.H., R.G.N. and J.A.R. supplied the GaAs μPV cells for concentrator optical efficiency measurements in the laboratory. G.S.B., X.M. and C.D.R. conceived the module design. N.C.G. supervised the project. J.S.P. and N.C.G. wrote the manuscript in consultation with all of the authors.

Competing interests

The authors declare that B.F., S.B. and J.A.R. (affiliated with Semprius) are involved in commercializing technologies related to those described here. J.A.R. is a co-founder of Semprius.

Corresponding author

Correspondence to Noel C. Giebink.

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