Nano Research

, Volume 4, Issue 12, pp 1181–1190 | Cite as

Sensitization of hydrothermally grown single crystalline TiO2 nanowire array with CdSeS nanocrystals for photovoltaic applications

  • Akshay Kumar
  • Kuan-teh Li
  • Anuj R. Madaria
  • Chongwu Zhou
Research Article


An oriented array of electron transporting nanowires, grown directly on a transparent conductor constitutes an optimal architecture for efficient photovoltaic applications. In addition, semiconductor nanocrystals can work as efficient light absorbers because of their tunable optical properties. In this paper, we use an oriented array of TiO2 nanowires grown directly on a transparent conductive electrode and subsequently sensitized with colloidally grown CdSeS nanocrystal quantum dots (QDs), using an efficient bi-linker assisted methodology, to demonstrate photovoltaic cells. Upon excitation with light, exciton dissociation takes place at the nanowire-nanocrystal interface, after which, electrons are transported to the fluorine-doped tin oxide (FTO) electrode via single-crystalline TiO2 nanowire channels. We demonstrate that an ex situ ligand exchange of QDs followed by sensitization on oxygen-plasma treated TiO2 nanowires results in enhanced loading of QDs, as compared to the in situ ligand exchange approach. An array of 1 μm long TiO2 nanowire sensitized with CdSeS nanocrystals exhibits photovoltaic effects with a short-circuit current of 2–3 mA/cm2, an open circuit voltage of 0.6–0.7 V and a fill factor of 52–65%, resulting in devices with efficiencies of up to 0.6%.


TiO2 nanowire semiconductor nanocrystals solar cells hydrothermal growth 


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Supplementary material

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  1. [1]
    Barnham, K. W. J.; Mazzer, M.; Clive, B. Resolving the energy crisis: Nuclear or photovoltaics? Nat. Mater. 2006, 5, 161–164.CrossRefGoogle Scholar
  2. [2]
    Kamat, P. V. Meeting the clean energy demand: Nanostructure architectures for solar energy conversion. J. Phys. Chem. C 2007, 111, 2834–2860.CrossRefGoogle Scholar
  3. [3]
    Gregg, B. A. Excitonic solar cells. J. Phys. Chem. B 2003, 107, 4688–4698.CrossRefGoogle Scholar
  4. [4]
    O’Regan, B.; Grätzel, M. A low-cost, high-efficiency solar cell based on dye-sensitized colloidal TiO2 films. Nature 1991, 353, 737–740.CrossRefGoogle Scholar
  5. [5]
    Chiba, Y.; Islam, A.; Watanabe, Y.; Komiya, R.; Koide, N.; Han, L. Dye-sensitized solar cells with conversion efficiency of 11.1%. Japan. J. Appl. Phys. 2006, 45, L638-L640.Google Scholar
  6. [6]
    Alivisatos, A. P. Semiconductor clusters, nanocrystals, and quantum dots. Science 1996, 271, 933–937.CrossRefGoogle Scholar
  7. [7]
    Murray, C. B.; Norris, D. J.; Bawendi, M. G. Synthesis and characterization of nearly monodisperse CdE (E = sulfur, selenium, tellurium) semiconductor nanocrystallites. J. Am. Chem. Soc. 1993, 115, 8706–8715.CrossRefGoogle Scholar
  8. [8]
    Qu, L.; Peng, X. Control of photoluminescence properties of CdSe nanocrystals in growth. J. Am. Chem. Soc. 2002, 124, 2049–2055.CrossRefGoogle Scholar
  9. [9]
    Chan, W. C. W.; Nie, S. Quantum dot bioconjugates for ultrasensitive nonisotopic detection. Science 1998, 281, 2016–2018.CrossRefGoogle Scholar
  10. [10]
    Schaller, R. D.; Klimov, V. I. High efficiency carrier multiplication in PbSe nanocrystals: Implications for solar energy conversion. Phys. Rev. Lett. 2004, 92, 186601.CrossRefGoogle Scholar
  11. [11]
    Schaller, R. D.; Sykora, M.; Pietryga, J. M.; Klimov, V. I. Seven excitons at a cost of one: Redefining the limits for conversion efficiency of photons into charge carriers. Nano Lett. 2006, 6, 424–429.CrossRefGoogle Scholar
  12. [12]
    Ellingson, R. J.; Beard, M. C.; Johnson, J. C.; Yu, P.; Micic, O. I.; Nozik, A. J.; Shaebev, A.; Efros, A. L. Highly efficient multiple exciton generation in colloidal PbSe and PbS quantum dots. Nano Lett. 2005, 5, 865–871.CrossRefGoogle Scholar
  13. [13]
    Fang, J.; Wu, J.; Lu, X.; Shen, Y.; Lu, Z. Sensitization of nanocrystalline TiO2 electrode with quantum sized CdSe and ZnTCPc molecules. Chem. Phys. Lett. 1997, 270, 145–151.CrossRefGoogle Scholar
  14. [14]
    Robel, I.; Subramanian, V.; Kuno, M.; Kamat, P. V. Quantum dot solar cells. Harvesting light energy with CdSe nanocrystals molecularly linked to mesoscopic TiO2 films. J. Am. Chem. Soc. 2006, 128, 2385–2393.CrossRefGoogle Scholar
  15. [15]
    Zaban, A.; Micic, O. I.; Nozik, A. J. Photosensitization of nanoporous TiO2 electrodes with InP quantum dots. Langmuir 1998, 14, 3153–3156.CrossRefGoogle Scholar
  16. [16]
    Plass, R.; Plete, S.; Krueger, J.; Grätzel, M. Quantum dot sensitization of organic-inorganic hybrid solar cells. J. Phys. Chem. B 2002, 106, 7578–7580.CrossRefGoogle Scholar
  17. [17]
    Bang, J. H.; Kamat, P. V. Quantum dot sensitized solar cells. A tale of two semiconductor nanocrystals: CdSe and CdTe. ACS Nano 2009, 3, 1467–1476.CrossRefGoogle Scholar
  18. [18]
    Peter, L. M.; Riley, D. J.; Tull, E. J.; Wijayantha, K. G. U. Photosensitization of nanocrystalline TiO2 by self-assembled layers of CdS quantum dots. Chem. Commun. 2002, 1030–1031.Google Scholar
  19. [19]
    Zhu, K.; Neale, N. R.; Miedaner, A.; Frank, A. J. Enhanced charge-collection efficiencies and light scattering in dye-sensitized solar cells using oriented TiO2 nanotubes arrays. Nano Lett. 2007, 7, 69–74.CrossRefGoogle Scholar
  20. [20]
    Mor, G. K.; Shankar, K.; Paulose, M.; Varghese, O. K.; Grimes, C. A. Use of highly-ordered TiO2 nanotube arrays in dye-sensitized solar cells. Nano Lett. 2006, 6, 215–218.CrossRefGoogle Scholar
  21. [21]
    Adachi, M.; Murata, Y.; Okada, I.; Yoshikawa, S. Formation of titania nanotubes and applications for dye-sensitized solar cells. J. Electrochem. Soc. 2003, 150, G488–G493.CrossRefGoogle Scholar
  22. [22]
    Kongkanand, A.; Tvrdy, K.; Takechi, K.; Kuno, M.; Kamat, P. V. Quantum dot solar cells. Tuning photoresponse through size and shape control of CdSe-TiO2 architecture. J. Am. Chem. Soc. 2008, 130, 4007–4015.CrossRefGoogle Scholar
  23. [23]
    van de Lagemaat, J.; Park, N. G.; Frank, A. J. Influence of electrical potential distribution, charge transport, and recombination on the photopotential and photocurrent conversion efficiency of dye-sensitized nanocrystalline TiO2 solar cells: A study by electrical impedance and optical modulation techniques. J. Phys. Chem. B 2000, 104, 2044–2052.CrossRefGoogle Scholar
  24. [24]
    Oekermann, T.; Zhang, D.; Yoshida, T.; Minoura, H. Electron transport and back reaction in nanocrystalline TiO2 films prepared by hydrothermal crystallization. J. Phys. Chem. B 2004, 108, 2227–2235.CrossRefGoogle Scholar
  25. [25]
    Lu, S.; Madhukar, A. Nonradiative resonant excitation transfer from nanocrystal quantum dots to adjacent quantum channels. Nano Lett. 2007, 7, 3443–3451.CrossRefGoogle Scholar
  26. [26]
    Greene, L. E.; Law, M.; Goldberger, J.; Kim, F.; Johnson, J. C.; Zhang, Y.; Saykally, R. J.; Yang, P. Low-temperature wafer-scale production of ZnO nanowire arrays. Angew. Chem. Int. Ed. 2003, 42, 3031–3034.CrossRefGoogle Scholar
  27. [27]
    Law, M.; Greene, L. E.; Johnson, J. C.; Saykally, R.; Yang, P. Nanowire dye-sensitized solar cells. Nat. Mater. 2005, 4, 455–459.CrossRefGoogle Scholar
  28. [28]
    Leschkies, K. S.; Divakar, R.; Basu, J.; Enache-Pommer, E.; Boercker, J. E.; Cartar, C. B.; Kortshagen, U. R.; Norris, D. J.; Aydil, E. S. Photosensitization of ZnO nanowires with CdSe quantum dots for photovoltaic devices. Nano Lett. 2007, 7, 1793–1798.CrossRefGoogle Scholar
  29. [29]
    Keis, K.; Lindgren J.; Lindquist, S. E.; Hagfeldt, A. Studies of the adsorption process of Ru complexes in nanoporous ZnO electrodes. Langmuir 2000, 16, 4688–4694.CrossRefGoogle Scholar
  30. [30]
    Kumar, A.; Madaria, A. R.; Zhou, C. Growth of aligned single-crystalline rutile TiO2 nanowires on arbitrary substrates and their application in dye-sensitized solar cells. J. Phys. Chem. C 2010, 114, 7787–7792.CrossRefGoogle Scholar
  31. [31]
    Liu, B.; Aydil, E. S. Growth of oriented single-crystalline rutile TiO2 nanorods on transparent conducting substrates for dye-sensitized solar cells. J. Am. Chem. Soc. 2009, 131, 3985–3990.CrossRefGoogle Scholar
  32. [32]
    Feng, X.; Shankar, K.; Varghese, O. K.; Paulose, M.; Latempa, T. J.; Grimes, C. A. Vertically aligned single crystal TiO2 nanowire arrays grown directly on transparent conducting oxide coated glass: Synthesis details and applications. Nano Lett. 2008, 8, 3781–3786.CrossRefGoogle Scholar
  33. [33]
    Robel, I.; Kuno, M.; Kamat, P. V. Size-dependent electron injection from excited CdSe quantum dots into TiO2 nanoparticles. J. Am. Chem. Soc. 2007, 129, 4136–4137.CrossRefGoogle Scholar
  34. [34]
    Koops, S. E.; O’Regan, B. C.; Barnes, P. R. F.; Durrant, J. R. Parameters influencing the efficiency of electron injection in dye-sensitized solar sells. J. Am. Chem. Soc. 2009, 131, 4808–4818.CrossRefGoogle Scholar
  35. [35]
    Haque, S. A.; Polomares, E.; Cho, B. M.; Green, A. N. M.; Hirata, N.; Klug, D. R.; Durrant, J. R. Charge separation versus recombination in dye-sensitized nanocrystalline solar cells: The minimization of kinetic redundancy. J. Am. Chem. Soc. 2005, 127, 3456–3462.CrossRefGoogle Scholar
  36. [36]
    Gimenez, S.; Maro-Sero, I.; Macor, L.; Guijarro, N.; Lana-Vilarreal, T.; Gomez, R.; Diguna, L. J.; Shen, Q.; Toyoda, T.; Bisquert, J. Improving the performance of colloidal quantum-dot-sensitized solar cells. Nanotechnology 2009, 20, 295204.CrossRefGoogle Scholar
  37. [37]
    Jang, E.; Jun, S.; Pu, L. High quality CdSeS nanocrystals synthesized by facile single injection process and their electroluminescence. Chem. Commun. 2003, 2964–2965.Google Scholar
  38. [38]
    Sarma, D. D.; Nag, A.; Santra, P. K.; Kumar, A.; Sapra, S.; Mahadevan, P. Origin of the enhanced photoluminescence from semiconductor CdSeS nanocrystals. J. Phys. Chem. Lett. 2010, 1, 2149–2153.CrossRefGoogle Scholar
  39. [39]
    Aldana, J.; Wang, Y. A.; Peng, X. Photochemical instability of CdSe nanocrystals coated by hydrophilic thiols. J. Am. Chem. Soc. 2001, 123, 8844–8850.CrossRefGoogle Scholar
  40. [40]
    Niitsoo, O.; Sarkar, S. K.; Pejoux, C.; Rühle, S.; Cahen, D.; Hodes, G. Chemical bath deposited CdS/CdSe-sensitized porous TiO2 solar cells. J. Photochem. Photobiol. A 2006, 181, 306–311.CrossRefGoogle Scholar
  41. [41]
    Nicolau, Y. F.; Dupuy, M.; Brunel, M. ZnS, CdS, and Zn1−xCdxS thin-film deposited by the successive ionic layer adsorption and reaction process. J. Electrochem. Soc. 1990, 137, 2915–2924.CrossRefGoogle Scholar
  42. [42]
    Kalyuzhny, G.; Murray, R. W. Ligand effects on optical properties of CdSe nanocrystals. J. Phys. Chem. B 2005, 109, 7012–7021.CrossRefGoogle Scholar
  43. [43]
    Aldana, J.; Lavelle, N.; Wang, Y.; Peng, X. Size-dependent dissociation pH of thiolate ligands from cadmium chalcogenide nanocrystals. J. Am. Chem. Soc. 2005, 127, 2496–2504.CrossRefGoogle Scholar
  44. [44]
    Sambur, J. B.; Parkinson, B. A. CdSe/ZnS core/shell quantum dot sensitization of low index TiO2 single crystal surfaces. J. Am. Chem. Soc. 2010, 132, 2130–2131.CrossRefGoogle Scholar

Copyright information

© Tsinghua University Press and Springer-Verlag Berlin Heidelberg 2011

Authors and Affiliations

  • Akshay Kumar
    • 1
  • Kuan-teh Li
    • 1
  • Anuj R. Madaria
    • 1
  • Chongwu Zhou
    • 1
  1. 1.Department of Electrical Engineering and Center for Energy Nanoscience and TechnologyUniversity of Southern CaliforniaLos AngelesUSA

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