Improved efficiency of dye-sensitized solar cells by design of a proper double layer photoanode electrodes composed of Cr-doped TiO2 transparent and light scattering layers
- 393 Downloads
A new strategy for enhancing the efficiency of TiO2 dye-sensitized solar cells (DSSCs) by design of a new double layer film doped with Cr ions, with various morphologies, is reported. X-ray diffraction and field emission scanning electron microscope (FE-SEM) analyses revealed that the synthesized nanoparticles had uniform and nanometer grains with different phase compositions and average crystallite size in the range of 10–12 nm depending upon Cr atomic percentage. UV–vis absorption showed that Cr introduction enhanced the visible light absorption of TiO2 nanoparticles by shifting the absorption onset to visible light region. Furthermore, the band gap energy of nanoparticles decreased with an increase in dopant concentration due to reduction of particle size. It was found that, 3 at.% Cr-doped TiO2 DSSC in the form of a double-layer film composed of TiO2 nanoparticles, as the under-layer, and mixtures of nano- and micro-particles with weight ratio of 80:20, as the over-layer, (i.e., CT3/NM3 solar cell) had the highest power conversion efficiency of 7.02 %, short current density of 17.32 mA/cm2 and open circuit voltage of 674 mV. This can be related to achievement of a balance among the electron injection, light scattering effect and dye sensitization parameters. Optimization of light scattering effect of photoanode electrode led to improve the photovoltaic performance of CT3/NM3 double-layer solar cell and was demonstrated by diffuse reflectance spectroscopy. The presented strategy would open up new insight into fabrication of low-cost TiO2 DSSCs with high power conversion efficiency.
KeywordsCr-doped TiO2 Dye-sensitized solar cell Light scattering effect Double layer film
The authors would like to thank Iran Nanotechnology Initiative Council for the financial support.
- 18.Johnson RW, Thiele ES, French RH (1997) Light-scattering efficiency of white pigments: an analysis of model core-shell pigments vs. optimized rutile TiO2. Tappi J 80:233–239Google Scholar
- 19.Ross WD (1971) Theoretical computation of light scattering power: comparison between TiO2 and air bubbles. J Paint Technol 43:50–66Google Scholar
- 23.Kong FT, Dai SY, Wang KJ (2007) Review of recent progress in dye-sensitized solar cells. Adv OptoElectron 2007:1–13Google Scholar
- 32.Yan BF, Chen B, Mahurin SM, Schwartz V, Mullins DR, Lupini AR, Pennycook SJ, Dai S, Overbury SH (2005) Preparation and comparison of supported gold nanocatalysts on anatase, brookite, rutile, and P25 polymorphs of TiO2 for catalytic oxidation of CO. J Phys Chem B 109:10676–10685CrossRefGoogle Scholar
- 34.Gribb A, Banfield JF (1997) Particle size effects on transformation kinetics and phase stability in nanocrystalline TiO2. Am Mineral 82:717–728Google Scholar
- 35.Cullity BD (1987) Elements of X-ray diffraction. Addison-Wesley Publishing Company, LondonGoogle Scholar