Quantum dot photoelectrochemical solar cells based on TiO₂-SrTiO₃ heterostructure nanotube array scaffolds

Abstract

Titania-Strontium titanate (TiO₂-SrTiO₃) nanotube array with heterostructure has been demonstrated as an efficient scaffold applied to quantum dot photoelectrochemical solar cells. Quantum dot CdS serviced as solar light absorbent is chosen as an example to illustrate superior performance and deposited on scaffolds by successive ionic layer adsorption and reaction (SILAR) technique. The photoelectrochemical performance of such solar cell is strongly dependent on the structure of heterostructured scaffolds. Only well-dispersed SrTiO₃ nanocrystallites on TiO₂ could improve the overall conversion efficiency. Transient absorption spectra and photoelectrochemical measurements show that the formation of SrTiO₃ energy gradient between TiO₂ and electrolyte slows down the rate of electronic injection from 19.3 × 10⁸ to 6.30 × 10⁸ s^-1, while it greatly increases electronic collection efficiency via reduced charge recombination. Cadmium sulfide (CdS) quantum dots used to decorate TiO₂-SrTiO₃ (1 h hydrothermal treatment) electrode exhibits superior photoelectrochemical performance with nearly 70% increase in external quantum efficiency at 460 nm and also in overall cell conversion efficiency. The photostability and high efficiency properties of TiO₂-SrTiO₃ composites would enable its practical application in solar energy conversion devices.

Keywords

quantum dot / heterostructure / nanotube array / photoelectrochemistry / TiO₂

References

[1] Kamat P V. Quantum dot solar cells. semiconductor nanocrystals as light harvesters. Journal of Physical Chemistry C, 2008, 112(48): 18737–18753

[2] Nozik A. Quantum dot solar cells. Journal of Physics of the Earth, 2002, 14(1–2): 115–120

[3] 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. Journal of the American Chemical Society, 2006, 128(7): 2385–2393

[4] Yu P, Zhu K, Norman A G, Ferrere S, Frank A J, Nozik A J. Nanocrystalline TiO₂ solar cells sensitized with InAs quantum dots. J Phys Chem B, 2006, 110(50): 25451–25454

[5] Luther J M, Law M, Beard M C, Song Q, Reese M O, Ellingson R J, Nozik A J. Schottky solar cells based on colloidal nanocrystal films. Nano Letters, 2008, 8(10): 3488–3492

[6] Weiss E A, Porter V J, Chiechi R C, Geyer S M, Bell D C, Bawendi M G, Whitesides G M. The use of size-selective excitation to study photocurrent through junctions containing single-size and multi-size arrays of colloidal CdSe quantum dots. Journal of the American Chemical Society, 2008, 130(1): 83–92

[7] Ross R T, Nozik A J. Efficiency of hot-carrier solar energy converters. Journal of Applied Physics, 1982, 53(5): 3813–3818

[8] Schaller R D, Klimov V I. High efficiency carrier multiplication in PbSe nanocrystals: implications for solar energy conversion. Physical Review Letters, 2004, 92(18): 186601

[9] Schaller R D, Agranovich V M, Klimov V C. High-efficiency carrier multiplication through direct photogeneration of multi-excitons via virtual single-exciton states. Nature Physics, 2005, 1(3): 189–194

[10] Luther J M, Beard M C, Song Q, Law M, Ellingson R J, Nozik A J. Multiple exciton generation in films of electronically coupled PbSe quantum dots. Nano Letters, 2007, 7(6): 1779–1784

[11] Niitsoo O, Sarkar S K, Pejoux C, Ruhle S, Cahen D, Hodes G J. Chemical bath deposited CdS/CdSe-sensitized porous TiO₂ solar cells. Photochemistry and Photobiology A, 2006, 181(2–3): 306–313

[12] Diguna L J, Shen Q, Kobayashi J, Toyoda T. High efficiency of CdSe quantum-dot-sensitized TiO₂ inverse opal solar cells. Applied Physics Letters, 2007, 91(2): 023116

[13] Hodes G. Comparison of dye- and semiconductor-sensitized porous nanocrystalline liquid junction solar cells. Journal of Physical Chemistry C, 2008, 112(46): 17778–17787

[14] Lee Y L, Lo Y S. Highly efficient quantum-dot-sensitized solar cell based on Co-sensitization of CdS/CdSe. Advanced Functional Materials, 2009, 19(4): 604–609

[15] Baker D R, Kamat P V. Photosensitization of TiO₂ nanostructures with CdS quantum dots. particulate versus tubular support architectures. Advanced Functional Materials, 2009, 19(5): 805–811

[16] Sun W T, Yu Y, Pan H Y, Gao X F, Chen Q, Peng L M. CdS quantum dots sensitized TiO₂ nanotube-array photoelectrodes. Journal of the American Chemical Society, 2008, 130(4): 1124–1125

[17] Robel I, Kuno M, Kamat P V. Size-dependent electron injection from excited CdSe quantum dots into TiO₂ nanoparticles. Journal of the American Chemical Society, 2007, 129(14): 4136–4137

[18] Kongkanand A, Tvrdy K, Takechi K, Kuno M K, Kamat P V. Quantum dot solar cells. Tuning photoresponse through size and shape control of CdSe-TiO₂ architecture. Journal of the American Chemical Society, 2008, 130(12): 4007–4015

[19] Leschkies K S, Divakar R, Basu J, Enache-Pommer E, Boercker J E, Carter C B, Kortshagen U R, Norris D J, Aydil E S. Photosensitization of ZnO nanowires with CdSe quantum dots for photovoltaic devices. Nano Letters, 2007, 7(6): 1793–1798

[20] Lee H J, Yum J H, Leventis H C, Zakeeruddin S M, Haque S A, Chen P, Seok S I, Gratzel M, Nazeeruddin M K. CdSe Quantum dot-sensitized solar cells exceeding efficiency 1% at full-sun Intensity. Journal of Physical Chemistry C, 2008, 112(30): 11600–11608

[21] Zaban A, Micic O I, Gregg B A, Nozik A J. Photosensitization of nanoporous TiO₂ electrodes with InP quantum dots. Langmuir, 1998, 14(12): 3153–3156

[22] Plass R, Pelet S, Krueger J, Gratzel M, Bach U. Quantum dot sensitization of organic-inorganic hybrid solar cells. Journal of Physical Chemistry B, 2002, 106(31): 7578–7580

[23] Law M, Greene L E, Johnson J C, Saykally R, Yang P. Nanowire dye-sensitized solar cells. Nature Materials, 2005, 4(6): 455–459

[24] Martinson A B F, Elam J W, Hupp J T, Pellin M J. ZnO nanotube based dye-sensitized solar cells. Nano Letters, 2007, 7(8): 2183–2187

[25] 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 Letters, 2006, 6(2): 215–218

[26] 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 Letters, 2007, 7(1): 69–74

[27] Jennings J R, Ghicov A, Peter L M, Schmuki P, Walker A B. Dye-sensitized solar cells based on oriented TiO₂ nanotube arrays: transport, trapping, and transfer of electrons. Journal of the American Chemical Society, 2008, 130(40): 13364–13372

[28] Shankar K, Basham J I, Allam N K, Varghese O K, Mor G K, Feng X, Paulose M, Seabold J A, Choi K S, Grimes C A. Recent Advances in the Use of TiO₂ Nanotube and Nanowire Arrays for Oxidative Photoelectrochemistry. Journal of Physical Chemistry C, 2009, 113(16): 6327–6359

[29] Diamant Y, Chen S G, Melamed O, Zaban A. Core-shell nanoporous electrode for dye sensitized solar cells:the effect of the SrTiO₃ shell on the electronic properties of the TiO2 core. Journal of Physical Chemistry B, 2003, 107(9): 1977–1981

[30] Diamant Y, Chappel S, Chen S G, Melamed O, Zaban A. Core-shell nanoporous electrode for dye sensitized solar cells: the effect of shell characteristics on the electronic properties of the electrode. Coordination Chemistry Reviews, 2004, 248(13–14): 1271–1276

[31] Bandaranayake K M P, Indika-Senevirathna M K, Prasad-Weligamuwa P M G M, Tennakone K. Dye-sensitized solar cells made from nanocrystalline TiO₂ films coated with outer layers of different oxide materials. Coordination Chemistry Reviews, 2004, 248(13–14): 1277–1281

[32] Nasr C, Kamat P V, Hotchandani S.. Photoelectrochemistry of composite semiconductor thin films. II. Photosensitization of SnO₂/TiO₂ coupled system with a ruthenium polypyridyl complex. Journal of Physical Chemistry B, 1998, 102(49): 10047–10056

[33] Zaban A, Chen S G, Chappel S, Gregg B A. Bilayer nanoporous electrodes for dye sensitized solar cells. Chemical Communications, 2000, 14(22): 2231–2232

[34] Wang Z S, Huang C H, Huang Y Y, Hou Y J, Xie P H, Zhang B W, Cheng H M. A highly efficient solar cell made from a dye-modified ZnO-covered TiO₂ nanoporous electrode. Chemistry of Materials, 2001, 13(2): 678–682

[35] Palomares E, Clifford J N, Haque S A, Lutz T, Durrant J R. Control of charge recombination dynamics in dye sensitized solar cells by the use of conformally deposited metal oxide blocking layers. Journal of the American Chemical Society, 2003, 125(2): 475–482

[36] Law M, Greene L E, Radenovic A, Kuykendall T, Liphardt J, Yang P. ZnO-A₂O₃ and ZnO-TiO₂ core-hell nanowire dye-sensitized solar cells. Journal of Physical Chemistry B, 2006, 110(45): 22652–22663

[37] Kang S H, Kim J Y, Kim Y, Kim H S, Sung Y E. Surface modification of stretched TiO₂ nanotubes for solid-state dye-sensitized solar cells. Journal of Physical Chemistry C, 2007, 111(26): 9614–9623

[38] Lee W, Kang S H, Kim J Y, Kolekar G B, Sung Y E, Han S H. TiO₂ nanotubes with a ZnO thin energy barrier for improved current efficiency of CdSe quantum-dot-sensitized solar cells. Nanotechnology, 2009, 20(33): 335706

[39] Zhang L, Cheng H, Zong R, Zhu Y. Photocorrosion suppression of ZnO nanoparticles via hybridization with graphite-like carbon and enhanced photocatalytic activity. Journal of Physical Chemistry C, 2009, 113(6): 2368–2374

[40] Fujihira M, Ohishi N, Osa T. Photocell using covalently-bound dyes on semiconductor surfaces. Nature, 1977, 268(5617): 226–228

[41] Zhang J, Bang J H, Tang C, Kamat P V. Tailored TiO₂-SrTiO₃ heterostructure nanotube arrays for improved photoelectrochemical performance. ACS Nano, 2010, 4(1): 387–395

[42] Zhang J, Tang C, Bang J H. CdS/TiO₂-SrTiO₃ heterostructure nanotube arrays for improved solar energy conversion efficiency. Electrochemistry Communications, 2010, 12(8): 1124–1128

[43] Nicolau Y F. Solution deposition of thin solid compound films by a successive ionic-layer adsorption and reaction process. Applications of Surface Science, 1985, 22–23(2): 1061–1074

[44] Likodimos V, Stergiopoulos T, Falaras P, Kunze J, Schmuki P. Phase composition, size, orientation, and antenna effects of self-assembled anodized titania nanotube arrays: a polarized micro-raman investigation. Journal of Physical Chemistry C, 2008, 112(33): 12687–12696

[45] Macák J M, Tsuchiya H, Schmuki P. High-aspect-ratio TiO₂ nanotubes by anodization of titanium. Angewandte Chemie International Edition, 2005, 44(14): 2100–2102

[46] James D R, Liu Y S, de Mayo P, Ware W R. Distributions of fluorescence lifetimes: consequences for the photophysics of molecules adsorbed on surfaces. Chemical Physics Letters, 1985, 120(4–5): 460–465

Acknowledgement:

This work was supported by the China Scholarship Council for the research grant. We gratefully acknowledge Dr. J H Bang, and Prof. P V Kamat for helpful discussion.

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2014 Higher Education Press and Springer-Verlag Berlin Heidelberg