Nanophotonic engineering shows great potential for photovoltaics: the record conversion efficiencies of nanowire solar cells are increasing rapidly1,2 and the record open-circuit voltages are becoming comparable to the records for planar equivalents3,4. Furthermore, it has been suggested that certain nanophotonic effects can reduce costs and increase efficiencies with respect to planar solar cells5,6. These effects are particularly pronounced in single-nanowire devices, where two out of the three dimensions are subwavelength. Single-nanowire devices thus provide an ideal platform to study how nanophotonics affects photovoltaics7,8,9,10,11,12. However, for these devices the standard definition of power conversion efficiency no longer applies, because the nanowire can absorb light from an area much larger than its own size6. Additionally, the thermodynamic limit on the photovoltage is unknown a priori and may be very different from that of a planar solar cell. This complicates the characterization and optimization of these devices. Here, we analyse an InP single-nanowire solar cell using intrinsic metrics to place its performance on an absolute thermodynamic scale and pinpoint performance loss mechanisms. To determine these metrics we have developed an integrating sphere microscopy set-up that enables simultaneous and spatially resolved quantitative absorption, internal quantum efficiency (IQE) and photoluminescence quantum yield (PLQY) measurements. For our record single-nanowire solar cell, we measure a photocurrent collection efficiency of >90% and an open-circuit voltage of 850 mV, which is 73% of the thermodynamic limit (1.16 V).
This is a preview of subscription content
Subscribe to Journal
Get full journal access for 1 year
only $8.25 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Aberg, I. et al. A GaAs nanowire array colar cell with 15.3% efficiency at 1 sun. IEEE J. Photovoltaics 6, 185–190 (2016).
Wallentin, J. et al. InP nanowire array solar cells achieving 13.8% efficiency by exceeding the ray optics limit. Science 339, 1057–1060 (2013).
Kayes, B. M. et al. 27.6% conversion efficiency, a new record for single-junction solar cells under 1 sun illumination. In Proc. 37th IEEE Photovoltaic Specialists Conf. 4–8 (IEEE, 2011).
Wanlass, M . Systems and methods for advanced ultra-high-performance InP solar cells. US patent 20150280042 (2015).
Polman, A. & Atwater, H. A. Photonic design principles for ultrahigh-efficiency photovoltaics. Nat. Mater. 11, 174–177 (2012).
Krogstrup, P. et al. Single-nanowire solar cells beyond the Shockley–Queisser limit. Nat. Photon. 7, 306–310 (2013).
Tian, B. et al. Coaxial silicon nanowires as solar cells and nanoelectronic power sources. Nature 449, 885–889 (2007).
Tang, J., Huo, Z., Brittman, S., Gao, H. & Yang, P. Solution-processed core–shell nanowires for efficient photovoltaic cells. Nat. Nanotech. 6, 568–572 (2011).
Holm, J. V. et al. Surface-passivated GaAsP single-nanowire solar cells exceeding 10% efficiency grown on silicon. Nat. Commun. 4, 1498 (2013).
Allen, J. E. et al. High-resolution detection of Au catalyst atoms in Si nanowires. Nat. Nanotech. 3, 168–173 (2008).
Nowzari, A. et al. A comparative study of absorption in vertically and laterally oriented InP core-shell nanowire photovoltaic devices. Nano Lett. 15, 1809–1814 (2015).
Kelzenberg, M. D. et al. Photovoltaic measurements in single-nanowire silicon solar cells. Nano Lett. 8, 710–714 (2008).
Crut, A., Maioli, P., Del Fatti, N. & Vallée, F. Optical absorption and scattering spectroscopies of single nano-objects. Chem. Soc. Rev. 43, 3921–3956 (2014).
Yorulmaz, M. et al. Single-particle absorption spectroscopy by photothermal contrast. Nano Lett. 15, 3041–3047 (2015).
Gaiduk, A., Yorulmaz, M., Ruijgrok, P. V. & Orrit, M. Room-temperature detection of a single molecule's absorption by photothermal contrast. Science 330, 353–356 (2010).
Arbouet, A. et al. Direct measurement of the single-metal-cluster optical absorption. Phys. Rev. Lett. 93, 127401 (2004).
Blancon, J.-C. et al. Direct measurement of the absolute absorption spectrum of individual semiconducting single-wall carbon nanotubes. Nat. Commun. 4, 2542 (2013).
Husnik, M. et al. Quantitative experimental determination of scattering and absorption cross-section spectra of individual optical metallic nanoantennas. Phys. Rev. Lett. 109, 233902 (2012).
Burkhard, G. F., Hoke, E. T. & McGehee, M. D. Accounting for interference, scattering, and electrode absorption to make accurate internal quantum efficiency measurements in organic and other thin solar cells. Adv. Mater. 22, 3293–3297 (2010).
Gargas, D. J., Gao, H., Wang, H. & Yang, P. High quantum efficiency of band-edge emission from ZnO nanowires. Nano Lett. 11, 3792–3796 (2011).
De Luca, M. et al. Polarized light absorption in wurtzite InP nanowire ensembles. Nano Lett. 15, 998–1005 (2015).
Leyre, S. et al. Absolute determination of photoluminescence quantum efficiency using an integrating sphere setup. Rev. Sci. Instrum. 85, 123115 (2014).
Rau, U. Reciprocity relation between photovoltaic quantum efficiency and electroluminescent emission of solar cells. Phys. Rev. B 76, 085303 (2007).
Green, M. A. Radiative efficiency of state-of-the-art photovoltaic cells. Prog. Photovoltaics 20, 472–476 (2012).
Cao, L. et al. Engineering light absorption in semiconductor nanowire devices. Nat. Mater. 8, 643–647 (2009).
Chu, S. N. G., Logan, R. A., Geva, M. & Ha, N. T. Concentration dependent Zn diffusion in InP during metalorganic vapor phase epitaxy. J. Appl. Phys. 78, 3001 (1995).
Van Weert, M. H. M. et al. Large redshift in photoluminescence of p-doped InP nanowires induced by Fermi-level pinning. Appl. Phys. Lett. 88, 043109 (2006).
Shockley, W. & Queisser, H. J. Detailed balance limit of efficiency of p-n junction solar cells. J. Appl. Phys. 32, 510 (1961).
Sandhu, S., Yu, Z. & Fan, S. Detailed balance analysis and enhancement of open-circuit voltage in single-nanowire solar cells. Nano Lett. 14, 1011–1015 (2014).
Yu, Z., Sandhu, S. & Fan, S. Efficiency above the Shockley–Queisser limit by using nanophotonic effects to create multiple effective bandgaps with a single semiconductor. Nano Lett. 14, 66–70 (2014).
Mårtensson, T. et al. Nanowire arrays defined by nanoimprint lithography. Nano Lett. 4, 699–702 (2004).
Pierret, A. et al. Generic nano-imprint process for fabrication of nanowire arrays. Nanotechnology 21, (2010).
We acknowledge A. Polman for the use of lab space and equipment and for a thorough reading of the manuscript, M. Seynen, H.-J. Boluijt and D. Verheijde for technical support and H.-J. Boluijt for the schematic in Fig. 1c. We would like to thank R. Van Veldhoven for maintaining the MOCVD system and M. Verheijen for the TEM measurements. We acknowledge Solliance for funding the TEM facility and the technical support from the NanoLab@TU/e cleanroom. The research leading to these results has received funding from the European Research Council under the European Union's Seventh Framework Programme ((FP/2007–2013)/ERC Grant Agreement No. 337328, ‘NanoEnabledPV’), the Dutch Technology Foundation STW (project 11826), which is part of the Netherlands Organization for Scientific Research (NWO), and the Dutch Ministry of Economic Affairs. This work is part of the research programme of the Foundation for Fundamental Research on Matter (FOM), which is part of The Netherlands Organization for Scientific Research (NWO).
The authors declare no competing financial interests.
About this article
Cite this article
Mann, S., Oener, S., Cavalli, A. et al. Quantifying losses and thermodynamic limits in nanophotonic solar cells. Nature Nanotech 11, 1071–1075 (2016). https://doi.org/10.1038/nnano.2016.162
Nature Communications (2018)