TY - JOUR
T1 - Controlling electron transport rate and recombination process of TiO 2 dye-sensitized solar cells by design of double-layer films with different arrangement modes
AU - Bakhshayesh, A. M.
AU - Mohammadi, M. R.
AU - Fray, D. J.
N1 - Funding - Iran nanotechnology Initiative Council
PY - 2012/9/1
Y1 - 2012/9/1
N2 - TiO 2 dye-sensitized solar cells (DSSCs) in the form of double-layer films, containing an under-layer and an over-layer, with various crystal structures (i.e., anatase and rutile phases) and morphologies (i.e., nanoparticle and nanowire) were reported. It was found that the photovoltaic performance of TiO 2 DSSCs depends on the morphology, crystal structure, light scattering effect, optical band gap energy and arrangement of the under- and over-layer films. The double-layer solar cell made of anatase-TiO 2 nanoparticles as the under-layer and anatase-TiO 2 nanowires as the over-layer (i.e., AW solar cell) showed the highest power conversion efficiency and fill factor of 6.34% and 62.6%, respectively. High electron lifetime, rapid transportation and less recombination of photogenerated electrons are the factors affect the efficiency improvement of AW film and was demonstrated by electrochemical impedance spectroscopy (EIS). X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM) analyses revealed that TiO 2 nanoparticles had uniform and nanometer grains with particle size around 20 nm, whereas TiO 2 nanowires with length of several μm had diameter in the range 20-50 nm. The optical properties and band gap energies of TiO 2 nanoparticles and nanowires were studied through UV-vis absorption. The indirect optical band gap energy of TiO 2 nanowires, anatase-TiO 2 and rutile-TiO 2 nanoparticles was calculated 3.61, 3.47 and 3.41 eV, respectively. The design of double-layer solar cells by manipulation of morphology and crystal structure of TiO 2 nanostructures will open a new concept for improvement of power conversion efficiency of dye sensitized solar cells.
AB - TiO 2 dye-sensitized solar cells (DSSCs) in the form of double-layer films, containing an under-layer and an over-layer, with various crystal structures (i.e., anatase and rutile phases) and morphologies (i.e., nanoparticle and nanowire) were reported. It was found that the photovoltaic performance of TiO 2 DSSCs depends on the morphology, crystal structure, light scattering effect, optical band gap energy and arrangement of the under- and over-layer films. The double-layer solar cell made of anatase-TiO 2 nanoparticles as the under-layer and anatase-TiO 2 nanowires as the over-layer (i.e., AW solar cell) showed the highest power conversion efficiency and fill factor of 6.34% and 62.6%, respectively. High electron lifetime, rapid transportation and less recombination of photogenerated electrons are the factors affect the efficiency improvement of AW film and was demonstrated by electrochemical impedance spectroscopy (EIS). X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM) analyses revealed that TiO 2 nanoparticles had uniform and nanometer grains with particle size around 20 nm, whereas TiO 2 nanowires with length of several μm had diameter in the range 20-50 nm. The optical properties and band gap energies of TiO 2 nanoparticles and nanowires were studied through UV-vis absorption. The indirect optical band gap energy of TiO 2 nanowires, anatase-TiO 2 and rutile-TiO 2 nanoparticles was calculated 3.61, 3.47 and 3.41 eV, respectively. The design of double-layer solar cells by manipulation of morphology and crystal structure of TiO 2 nanostructures will open a new concept for improvement of power conversion efficiency of dye sensitized solar cells.
KW - Double-layer
KW - Dye-sensitized solar cell
KW - EIS
KW - TiO nanoparticles
KW - TiO nanowires
UR - http://www.scopus.com/inward/record.url?scp=84864282832&partnerID=8YFLogxK
U2 - 10.1016/j.electacta.2012.06.087
DO - 10.1016/j.electacta.2012.06.087
M3 - Article
AN - SCOPUS:84864282832
SN - 0013-4686
VL - 78
SP - 384
EP - 391
JO - Electrochimica Acta
JF - Electrochimica Acta
ER -
