Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Solution-processed inorganic bulk nano-heterojunctions and their application to solar cells

Abstract

In the last decade, solution-processed quantum dot/nanocrystal solar cells have emerged as a very promising technology for third-generation thin-film photovoltaics because of their low cost and high energy-harnessing potential. Quantum dot solar cell architectures developed to date have relied on the use of bulk-like thin films of colloidal quantum dots. Here, we introduce the bulk nano-heterojunction concept for inorganic solution-processed semiconductors. This platform can be readily implemented by mixing different semiconductor nanocrystals in solution and allows for the development of optoelectronic nanocomposite materials with tailored optoelectronic properties. We present bulk nano-heterojunction solar cells based on n-type Bi2S3 nanocrystals and p-type PbS quantum dots, which demonstrate a more than a threefold improvement in device performance compared to their bilayer analogue, as a result of suppressed recombination.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Bilayer and BNH device structures.
Figure 2: Solar cell characterization of bilayer and BNH devices.
Figure 3: Device physics and carrier lifetime studies in bilayer and BNH devices.
Figure 4: BNH device optimization studies.

Similar content being viewed by others

References

  1. Luther, J. M. et al. Schottky solar cells based on colloidal nanocrystal films. Nano Lett. 8, 3488–3492 (2008).

    Article  ADS  Google Scholar 

  2. Ma, W. et al. Photovoltaic performance of ultrasmall PbSe quantum dots. ACS Nano 5, 8140–8147 (2011).

    Article  Google Scholar 

  3. Pattantyus-Abraham, A. G. et al. Depleted-heterojunction colloidal quantum dot solar cells. ACS Nano 4, 3374–3380 (2010).

    Article  Google Scholar 

  4. Brown, P. R. et al. Improved current extraction from ZnO/PbS quantum dot heterojunction photovoltaics using a MoO3 interfacial layer. Nano Lett. 11, 2955–2961 (2011).

    Article  ADS  Google Scholar 

  5. Jasieniak, J., MacDonald, B. I., Watkins, S. E. & Mulvaney, P. Solution-processed sintered nanocrystal solar cells via layer-by-layer assembly. Nano Lett. 11, 2856–2864 (2011).

    Article  ADS  Google Scholar 

  6. Panthani, M. G. et al. Synthesis of CuInS2, CuInSe2, and CuInxGa1–xSe2 (CIGS) nanocrystal ‘inks’ for printable photovoltaics. J. Am. Chem. Soc. 130, 16770–16777 (2008).

    Article  Google Scholar 

  7. Guo, Q., Hillhouse, H. W. & Agrawal, R. Synthesis of Cu2ZnSnS4 nanocrystal ink and its use for solar cells. J. Am. Chem. Soc. 131, 11672–11673 (2009).

    Article  Google Scholar 

  8. Luther, J. M. et al. Stability assessment on a 3% bilayer PbS/ZnO quantum dot heterojunction solar cell. Adv. Mater. 22, 3704–3707 (2010).

    Article  Google Scholar 

  9. Tang, J. et al. Quantum dot photovoltaics in the extreme quantum confinement regime: the surface-chemical origins of exceptional air- and light-stability. ACS Nano 4, 869–878 (2010).

    Article  Google Scholar 

  10. Gur, I., Fromer, N. A., Geier, M. L. & Alivisatos, A. P. Air-stable all-inorganic nanocrystal solar cells processed from solution. Science 310, 462–465 (2005).

    Article  ADS  Google Scholar 

  11. Wang, X. et al. Tandem colloidal quantum dot solar cells employing a graded recombination layer. Nature Photon. 5, 480–484 (2011).

    Article  ADS  Google Scholar 

  12. Choi, J. J. et al. Solution-processed nanocrystal quantum dot tandem solar cells. Adv. Mater. 23, 3144–3148 (2011).

    Article  Google Scholar 

  13. Barkhouse, D. A. R., Pattantyus-Abraham, A. G., Levina, L. & Sargent, E. H. Thiols passivate recombination centers in colloidal quantum dots leading to enhanced photovoltaic device efficiency. ACS Nano 2, 2356–2362 (2008).

    Article  Google Scholar 

  14. Tang, J. et al. Colloidal-quantum-dot photovoltaics using atomic-ligand passivation. Nature Mater. 10, 765–771 (2011).

    Article  ADS  Google Scholar 

  15. Yu, G., Gao, J., Hummelen, J. C., Wudl, F. & Heeger, A. J. Polymer photovoltaic cells—enhanced efficiencies via a network of internal donor–acceptor heterojunctions. Science 270, 1789–1791 (1995).

    Article  ADS  Google Scholar 

  16. Oosterhout, S. D. et al. The effect of three-dimensional morphology on the efficiency of hybrid polymer solar cells. Nature Mater. 8, 818–824 (2009).

    Article  ADS  Google Scholar 

  17. Ren, S. et al. Inorganic–organic hybrid solar cell: bridging quantum dots to conjugated polymer nanowires. Nano Lett. 11, 3998–4002 (2011).

    Article  ADS  Google Scholar 

  18. Barkhouse, D. A. R. et al. Depleted bulk heterojunction colloidal quantum dot photovoltaics. Adv. Mater. 23, 3134–3138 (2011).

    Article  Google Scholar 

  19. Rath, A. K., Bernechea, M., Martinez, L. & Konstantatos, G. Solution-processed heterojunction solar cells based on p-type PbS quantum dots and n-type Bi2S3 nanocrystals. Adv. Mater. 23, 3712–3717 (2011).

    Article  Google Scholar 

  20. Johnston, K. W. et al. Efficient Schottky–quantum-dot photovoltaics: the roles of depletion, drift, and diffusion. Appl. Phys. Lett. 92, 122111 (2008).

    Article  ADS  Google Scholar 

  21. Zhao, N. et al. Colloidal PbS quantum dot solar cells with high fill factor. ACS Nano 4, 3743–3752 (2010).

    Article  Google Scholar 

  22. Snaith, H. J. et al. Efficiency enhancements in solid-state hybrid solar cells via reduced charge recombination and increased light capture. Nano Lett. 7, 3372–3376 (2007).

    Article  ADS  Google Scholar 

  23. Ohnesorge, B. et al. Minority-carrier lifetime and efficiency of Cu(In,Ga)Se2 solar cells. Appl. Phys. Lett. 73, 1224–1226 (1998).

    Article  ADS  Google Scholar 

  24. Urban, J. J., Talapin, D. V., Shevchenko, E. V., Kagan, C. R. & Murray, C. B. Synergismin binary nanocrystal superlattices leads to enhanced p-type conductivity in self-assembled PbTe/Ag2Te thin films. Nature Mater. 6, 115–121 (2007).

    Article  ADS  Google Scholar 

  25. Ko, D.-K., Urban, J. J. & Murray, C. B. Carrier distribution and dynamics of nanocrystal solids doped with artificial atoms. Nano Lett. 10, 1842–1847 (2010).

    Article  ADS  Google Scholar 

  26. Talapin, D. V. & Murray, C. B. PbSe nanocrystal solids for n- and p-channel thin film field-effect transistors. Science 310, 86–89 (2005).

    Article  ADS  Google Scholar 

  27. Wolcott, A. et al. Anomalously large polarization effect responsible for excitonic red shifts in PbSe quantum dot solids. J. Phys. Chem. Lett. 2, 795–800 (2011).

    Article  Google Scholar 

  28. Lee, J.-S., Kovalenko, M. V., Huang, J., Chung, D. S. & Talapin, D. V. Band-like transport, high electron mobility and high photoconductivity in all-inorganic nanocrystal arrays. Nature Nanotech. 6, 348–352 (2011).

    Article  ADS  Google Scholar 

  29. Fafarman, A. T. et al. Thiocyanate-capped nanocrystal colloids: vibrational reporter of surface chemistry and solution-based route to enhanced coupling in nanocrystal solids. J. Am. Chem. Soc. 133, 15753–15761 (2011).

    Article  Google Scholar 

  30. Nag, A. et al. Metal-free inorganic ligands for colloidal nanocrystals: S2−, HS, Se2−, HSe, Te2−, HTe, TeS32−, OH, and NH2 as surface ligands. J. Am. Chem. Soc. 133, 10612–10620 (2011).

    Article  Google Scholar 

Download references

Acknowledgements

The authors acknowledge financial support from Fundació Privada Cellex Barcelona and the European Union FP7 IRG programme (contract PIRG06-GA-2009-256355). The authors thank N. van Hulst and M. Kuttge for assistance with the transient photoluminescence measurements and for providing access to the focused ion beam (FIB) system for device inspection.

Author information

Authors and Affiliations

Authors

Contributions

G.K. supervised the study and wrote the manuscript. A.K.R. fabricated all the devices and contributed to all characterization techniques and data analysis. M.B. synthesized the materials and contributed to material characterization data analysis. L.M. contributed to device characterization and data analysis. F.P.G.A. contributed to data analysis. J.O. contributed to structural characterization and analysis. All authors provided inputs to data analysis, discussed the results and assisted in manuscript preparation.

Corresponding author

Correspondence to Gerasimos Konstantatos.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

Supplementary information (PDF 2483 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Rath, A., Bernechea, M., Martinez, L. et al. Solution-processed inorganic bulk nano-heterojunctions and their application to solar cells. Nature Photon 6, 529–534 (2012). https://doi.org/10.1038/nphoton.2012.139

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nphoton.2012.139

This article is cited by

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing