Kongjia Wang

Review of Recent Progress in Dye-Sensitized Solar Cells

We introduced the structure and the principle of dye-sensitized solar cell (DSC). The latest results about the critical technology and the industrialization research on dye-sensitized solar cells were reviewed. The development of key components, including nanoporous semiconductor films, dye sensitizers, redox electrolyte, counter electrode, and conducting substrate in dye-sensitized solar cells was reviewed in detail. The developing progress and prospect of dye-sensitized solar cells from small cells in the laboratory to industrialization large-scale production were reviewed. At last, the future development of DSC was prospective for the tendency of dye-sensitized solar cells.

Low molecular mass organogelator based gel electrolyte with effective charge transport property for long-term stable quasi-solid-state dye-sensitized solar cells.

Stable quasi-solid-state dye-sensitized solar cells (DSC) were fabricated using 12-hydroxystearic acid as a low molecular mass organogelator (LMOG) to form gel electrolyte. TEM image of the gel exhibited the self-assembled network constructed by the LMOG, which hindered flow and volatilization of the liquid. The formation of less-mobile polyiodide ions such as I 3 (-) and I 5 (-) confirmed by Raman spectroscopy increased the conductivity of the gel electrolytes by electronic conduction process, which should be rationalized by the Grotthuss-type electron exchange mechanism caused by rather packed polyiodide species in the electrolytes. The results of the accelerated aging tests showed that the gel electrolyte based dye-sensitized solar cell could retain over 97% of its initial photoelectric conversion efficiency value after successive heating at 60 degrees C for 1000 h and device degradation was also negligible after one sun light soaking with UV cutoff filter for 1000 h.

The Transportand Recombination Kinetics in Dye-Sensitized Solar Cells with Different Nanoporous Films

The high light-to-energy conversion efficiencies achieved with dye-sensitized solar cells may be attributed to the nanoporous TiO2 electrodes. Nanoporous electrode films are prepared from different sized anatase TiO2 nanoparticles, of which the crystalline size is 13.4 and 17.5 nm, and DSCs are prepared from these films. Intensity modulated photocurrent spectroscopy has been used to obtain values of the electron diffusion coefficient. Intensity modulated photovoltage spectroscopy is shown to be valuable in achieving the different electron lifetime during the electron transport process resulting from different crystalline size and thickness of TiO2 films. The transport and recombination kinetics was discussed by investigating the change of the absorption coefficient, electron diffusion coefficient and electron lifetime in the cells. The results implied that the films morphology influence the electron transport and back reaction processes.

Design, Synthesis and Characterization of Amphiphilic Bipyridyl Ruthenium (II) Sensitizers

Dye-sensitized solar cells (DSC), as a new innovation technology, have developed very quickly in the past decade since the breakthrough was accomplished by attaching ruthenium polypyridyl complexes to high surface area titania film electrode. Gratzel and co-workers have developed DSC with the efficiency over 10% under AM 1.5 solar radiation using cis-Ru(dcbpy)2(NCS)2 (known as the N3 dye, Where dcbpy = 2,2′-bipyridyl-4,4′-dicarboxylic acid) as sensitizer, in conjunction with organic solvent electrolyte containing iodide/triiodide redox couple. However, the disadvantages of exhibiting high energy absorption bands which only harvest a fraction of visible light and easy desorption from the titanium dioxide surface have restrict the practical application of dye-sensitized solar cells.