Characteristics of SnO2 nanofiber/TiO2 nanoparticle composite for dye-sensitized solar cells (original) (raw)
Related papers
IEEE Electron Device Letters, 2014
Incorporation of TiO 2 nanoparticles into SnO 2 nanofibers as photoanode in dye-sensitized solar cells improved the cell efficiency from 4.63% to 6.17%. The addition of TiO 2 nanoparticles increased the surface area of the photoanode that led to the enhancement in the dye attachment. In addition, the incorporation of TiO 2 nanoparticles helped in the reduction of the recombination of electrons in the photoanode with the electrolyte resulting in the increase in the open circuit voltage (V oc) and fill factor. Index Terms-SnO 2 nanofibers, TiO 2 nanoparticles, dyesensitized solar cells.
Surface properties of SnO2 nanowires for enhanced performance with dye-sensitized solar cells
2009
Our recent studies showed that nanowire based DSSCs exhibited over 250 mV higher open circuit potentials (V OC) compared to those using nanoparticles. In this study, the electron transport and surface properties of nanowires and nanoparticles are investigated to understand the reasons for the observed higher photovoltages with NW based solar cells. It was seen that, in addition to slow recombination kinetics, the lower work function of SnO 2 nanowires compared to the nanoparticle counterparts also significantly contributes to the high V OC observed for the nanowire based DSSCs.
Multiporous nanofibers of SnO 2 by electrospinning for high efficiency dye-sensitized solar cells
Various one-dimensional nano-morphologies, such as multiporous nanofibers (MPNFs), porous nanofibers (PNFs), and nanowires (NWs) of SnO 2 , are synthesized using electrospinning technique by controlling the tin precursor concentration. The MPNFs have 8−foldhighersurfaceareacomparedtotheothermorphologies.Dye−sensitizedsolarcells(DSCs)werefabricatedusingthesenanostructuresasphotoanodesandtheirperformancewascompared.TheMPNFssurpasstheperformanceofPNFsandNWsaswellasconventionalTiO2paste.Recordphotoconversionefficiency(PCE)of8-fold higher surface area compared to the other morphologies. Dye-sensitized solar cells (DSCs) were fabricated using these nanostructures as photoanodes and their performance was compared. The MPNFs surpass the performance of PNFs and NWs as well as conventional TiO 2 paste. Record photoconversion efficiency (PCE) of 8−foldhighersurfaceareacomparedtotheothermorphologies.Dye−sensitizedsolarcells(DSCs)werefabricatedusingthesenanostructuresasphotoanodesandtheirperformancewascompared.TheMPNFssurpasstheperformanceofPNFsandNWsaswellasconventionalTiO2paste.Recordphotoconversionefficiency(PCE)of7.4% was realized in MPNFs DSCs, which was twice to that achieved using PNFs ($3.5%). Furthermore, the MPNFs showed over >80% incident photon to current conversion efficiency (22% higher than that achieved by spherical P25 TiO 2 particles) and also demonstrated $3 times longer electron lifetime and electron diffusion length. Owing to the possibility to produce large quantities using electrospinning technique, huge commercial potential of SnO 2 nanostructures, and promising results achieved herein, the MPNFs are expected soon to be utilized in commercial devices. . my † Electronic supplementary information (ESI) available: S1 -SEM images of the as-spun polymeric nanobers with varying tin precursor concentration and their XRD patterns in S2; S3results of dye-loading test; S4measured OCVD curves; S5-S8: extraction of charge transport parameters. See
Electrochimica Acta, 2012
Efficiency of dye-sensitized solar cells (DSSC) fabricated with pristine SnO 2 nanocrystals was reported to be less superior compared to DSSC based on mesoporous TiO 2 nanoparticles though both oxides have comparable electrical and surface properties. Owing to inherent high charge recombination properties of SnO 2 nanoparticles, photoanode fabricated with SnO 2 nanoparticles resulting in unexpected low open circuit voltage (V oc ) and fill factor (FF). To overcome inherent charge recombination in SnO 2 , we investigated pristine SnO 2 nanorods and showed enhanced V oc , FF and overall conversion efficiency (Á) for SnO 2 nanorods. The photoanode made of SnO 2 nanorods yields nearly a 2-fold improvement in fill factor, 5 fold increases in Á and a greater than 2-fold increase in short-circuit current density with a moderate increase in open-circuit photovoltage. The effects appear to arise primarily from longer electron lifetimes and reduced charge recombination of SnO 2 nanorod based solar cells compared to that of SnO 2 particles owing to 1-D nature of SnO 2 nanorod which were evaluated by open-circuit voltage decay (OCVD) and electrochemical impedance spectroscopy (EIS) methods.
Nanocrystalline SnO 2 powders prepared by solvothermal and co-precipitation pathways have been characterized using XRD, TEM, UV-Visible absorption, BET specific surface area (S BET) method, EIS and J-V measurements. The obtained powders have a surface area and size of 38⋅59 m 2 /g and 10⋅63 nm for the SnO 2 powders synthesized solvothermally at a temperature of 200 °C for 24 h, while the values were 32⋅59 m 2 /g and 16⋅20 nm for the formed hydroxide precursor annealed at 1000 °C for 2 h by co-precipitation route. The microstructure of the formed powders appeared as tetragonal-like structure. Thus, the prepared SnO 2 nanopowders using two pathways were applied as an electrode in dye-sensitized solar cell (DSSC). The photoelectrochemical measurements indicated that the cell presents short-circuit photocurrent (J sc), open circuit voltage (V oc) and fill factor (FF) were 7⋅017 mA/cm 2 , 0⋅690 V and 69⋅68%, respectively, for solvothermal route and they were 4⋅241 mA/cm 2 , 0⋅756 V and 66⋅74%, respectively, for co-precipitation method. The energy conversion efficiency of the solvothermal SnO 2 powders was considerably higher than that formed by co-precipitation powders; approximately 3⋅20% (solvothermal) and 2⋅01% (co-precipitation) with the N719 dye under 100 mW/cm 2 of simulated sunlight, respectively. These results were in agreement with EIS study showing that the electrons were transferred rapidly to the surface of the solvothermal-modified SnO 2 nanoparticles, compared with that of a co-precipitation-modified SnO 2 nanoparticles. Keywords. SnO 2 nanoparticle; co-precipitation method; solvothermal processes; dye sensitized solar cells.
TiO 2 coated urchin-like SnO 2 microspheres for efficient dye-sensitized solar cells
Nano Research, 2014
Urchin-like SnO 2 microspheres have been grown for use as photoanodes in dye-sensitized solar cells (DSSCs). We observed that a thin layer coating of TiO 2 on urchin-like SnO 2 microsphere photoanodes greatly enhanced dye loading capability and light scattering ability, and achieved comparable solar cell performance even at half the thickness of a typical nanocrystalline TiO 2 photoanode. In addition, this photoanode only required attaching ~55% of the amount of dye for efficient light harvesting compared to one based on nanocrystalline TiO 2. Longer decay of transient photovoltage and higher charge recombination resistance evidenced from electrochemical impedance spectroscopy of the devices based on TiO 2 coated urchin-like SnO 2 revealed slower recombination rates of electrons as a result of the thin blocking layer of TiO 2 coated on urchin-like SnO 2. TiO 2 coated urchin-like SnO 2 showed the highest value (76.1 ms) of electron lifetime (τ) compared to 2.4 ms for bare urchin-like SnO 2 and 14.9 ms for nanocrystalline TiO 2. TiO 2 coated SnO 2 showed greatly enhanced open circuit voltage (V oc), short-circuit current density (J sc) and fill factor (FF) leading to a four-fold increase in efficiency increase compared to bare SnO 2. Although TiO 2 coated urchin-like SnO 2 showed slightly lower cell efficiency than nanocrystalline TiO 2 , it only used a half thickness of photoanode and saved ~45% of the amount of dye for efficient light harvesting compared to normal nanocrystalline TiO 2 .
Solar Energy Materials and Solar Cells, 2002
This paper reports on the synthesis of SnO 2 18 nm diameter colloidal suspension for the fabrication of nanoporous electrodes. The new suspension allows the fabrication of thick and homogeneous electrodes by simple one layer spreading; in contrast to the successive spin coating of the commonly used commercial suspension that results in a thin inhomogeneous electrode. When used in dye-sensitized solar cells, the new electrodes increase the light-toenergy conversion efficiency by a factor of 2.1 in comparison with standard commercial suspension based electrodes. The improvement is mostly the result of an increase of the photocurrent. This increase is attributed to the better electrolyte migration, and presumably also to an increase of the photoinjected electron diffusion rate in the electrode. r (A. Zaban). 0927-0248/02/$ -see front matter r 2002 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 7 -0 2 4 8 ( 0 1 ) 0 0 0 5 0 -2
We report the fabrication and testing of dye sensitized solar cells (DSSC) based on tin oxide (SnO 2) particles of average size ~20 nm. Fluorine-doped tin oxide (FTO) conducting glass substrates were treated with TiO x or TiCl 4 precursor solutions to create a blocking layer before tape casting the SnO 2 mesoporous anode. In addition, SnO 2 photoelectrodes were treated with the same precursor solutions to deposit a TiO 2 passivating layer covering the SnO 2 particles. We found that the modification enhances the short circuit current, open-circuit voltage and fill factor, leading to nearly 2-fold increase in power conversion efficiency, from 1.48% without any treatment, to 2.85% achieved with TiCl 4 treatment. The superior photovoltaic performance of the DSSCs assembled with modified photoanode is attributed to enhanced electron lifetime and suppression of electron recombination to the electrolyte, as confirmed by electrochemical impedance spectroscopy (EIS) carried out under dark condition. These results indicate that modification of the FTO and SnO 2 anode by titania can play a major role in maximizing the photo conversion efficiency.
Hybrid TiO2–SnO2 Nanotube Arrays for Dye-Sensitized Solar Cells
The Journal of Physical Chemistry C, 2013
Tin oxide (SnO 2) is a promising wide band gap semiconductor material for dye-sensitized solar cells (DSCs) because of its high bulk electron mobility. Employing vertically ordered 1-D nanostructures of SnO 2 as the photoanode may overcome the limit of current DSCs by using new redox mediators with faster kinetics than currently used ones. Synthesizing such nanostructures and integrating them into DSCs, however, has been proven challenging. Here, we demonstrate that, by using ZnO nanowires as a sacrificial template, vertically aligned SnO 2 nanotube arrays may be feasibly synthesized through a liquid-phase conversion process, and the synthesized SnO 2 nanotubes can be further coated with a thin layer of TiO 2 to form hybrid TiO 2 −SnO 2 nanotube arrays. Both the resulting SnO 2 and hybrid TiO 2 −SnO 2 nanotube arrays are used to fabricate DSCs, and the best performing cell delivers a promising efficiency of 3.53%. Transient photovoltage measurements indicate that the electron recombination lifetime in hybrid TiO 2 −SnO 2 nanotubes is significantly larger than those in TiO 2 nanotubes, ZnO nanowires, and films of sintered TiO 2 nanoparticles, suggesting promise of the TiO 2-coated SnO 2 nanotubes for further improvement of DSCs.