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1.
A novel polymer gel electrolyte was used to improve the performance and long-term stability in dye-sensitized solar cells (DSSCs). The polymer gel electrolyte (PGE) was prepared by mixing 5 wt% poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and 2 % TiO2 nanoparticles. The conductivity of PGE with P25 reached 9.98 × 10?3 S/cm, which increased by 34.9 % compared with 7.40 × 10?3 S/cm of PGE without P25, and the diffusion coefficient was also increased by 19.0 %. Different photoelectrodes were obtained by using three kinds of surfactants (cetylamine, octadecylamine, and P123) as pore-forming materials, and their morphologies were contrasted through scanning electron microscopy (SEM). The results showed that gel electrolyte can increase the short-circuit current density (J sc) from 11.01 to 12.99 mA/cm2 in DSSCs. Moreover, unlike the liquid electrolyte, the gel electrolyte is more conducive to the TiO2 photoelectrodes with larger pores. In conclusion, the efficiency of DSSC with gel electrolyte and P123 as pore-forming material was 6.73 %, which was 12 % higher than the liquid electrolyte in the same test condition. In addition, the sealed gel electrolyte DSSCs showed better stability than did liquid electrolyte DSSCs during nearly 600 h.  相似文献   

2.
A hybrid of polymer/dispersed single-wall carbon nanotubes was utilized in networking a novel composition of gel electrolyte in dye-sensitized solar cells. The gel is composed of polyethylene glycol, polyvinyl pyrrolidone, single-wall carbon nanotubes, and I?/I3 ? as electrolyte. Formation of the less conductive polyiodide species in electrolyte was prohibited by the addition of single-wall carbon nanotubes leading to the excellent photovoltaic behavior of the cell under simulated standard illumination of the fabricated device owing to the increased open circuit voltage (0.47 V). Electrochemical impedance spectroscopy was employed to quantify the charge transport resistance and the electron lifetime at the TiO2 conduction band. Charge transport resistances at the TiO2/dye/electrolyte interface were determined for the cells consisting of the non-gel reference and our new gel electrolytes, and it was indicated that the charge recombination between injected electrons and electron acceptors (I3 ?) in the redox electrolyte was remarkably retarded. Electrochemical parameters obtained by the fitting showed all of the resistances increased as compared to liquid electrolyte dye-sensitized solar cells that can be related to the increase in viscosity of the gel, which hinders the ionic transportation through the electrolyte. These results were also confirmed by the electron lifetime analyses. The characteristic peak shifted to a lower frequency in the Bode phase plot for the cell containing gel electrolyte which is an indication of a longer electron lifetime in comparison with that of the cell containing very conventional liquid electrolyte.  相似文献   

3.
In this work, we have synthesized Zinc oxide (ZnO) tripods and used its thin film as photoanode in dye-sensitized solar cells. SEM micrographs of the as-prepared sample of ZnO confirmed tripod-like morphology consisting of three cylindrical arms with well-defined ends, joined at a common core. The prepared sample of ZnO tripods was further characterized by EDX, XRD, UV-VIS, and FTIR. The dye N719-sensitized solar cell fabricated with photoanode of ZnO prepared in this work provided the open-circuit photo voltage (V oc)?=?0.558 V, short-circuit photocurrent (J sc)?=?6.368 mA?cm-2, fill factor (FF)?=?0.50, and total conversion efficiency (η)?=?0.88 % under full light illumination (intensity 200 mW?cm?2). When cell was illuminated by visible light (150 mW/cm2), V oc?=?0.546 V, J sc?=?4.437 mA/cm2, FF?=?0.54, and η?=?0.88 % were obtained.  相似文献   

4.
This paper describes an application of a new electro-deposition method in a modulated electrical field in order to have an efficient semiconductor coating on a conductive substrate. The prepared film was used as a photoanode of dye-sensitized solar cells (DSSCs). Electro-deposition of nanoparticles usually was performed by applying a DC electrical field in a suspension. In the DC field, a homogeneous layer could not be performed because of unwanted electrochemical reactions that might occur on the substrate surface. Modulated electrical fields based on pulsed AC and a sweeping voltage profile were used. The photovoltaic performance of the assembled solar cells showed a significant difference between the films produced in different electrical field conditions. Under the illumination of simulated AM 1.5 sunlight (100 mW cm?2) with an aperture black mask, the energy conversion efficiency of 2.45% (V OC = 768 mV, J SC = 4.74 mA cm?2, FF = 67%) was obtained with a thin layer of TiO2 nanoparticles deposited in a pulsed waveform voltage. A crack-free and uniform porous layer produced in this condition showed an enhancement of about seven times over the photoanode prepared using conventional DC electrical field with the same voltage amplitude. The solar cell efficiency was increased to 4.22% (V OC = 735 mV, J SC = 7.92 mA cm?2, FF = 72%) by just increasing the TiO2 film thickness and using a blocking layer beneath the semiconductor layer. Moreover, a higher electron recombination lifetime presented better electron transport and collection efficiency of the film deposited in the pulsed electrical field conditions.  相似文献   

5.
Polyethylene-supported polymethyl methacrylate/poly(vinylidene fluoride-co-hexafluoropropylene) separator for gel polymer lithium-ion battery use was prepared with a mixed solvent of n-butanol and acetone. The prepared separator was characterized with scanning electron spectroscopy and X-ray diffraction, and its performance was investigated by electrochemical impedance spectroscopy and battery charge/discharge test. Compared to the separator prepared with acetone, the separator prepared with the mixed solvent shows an enhanced porosity (from 42 to 49 %) and electrolyte uptake (from 104 to 125 %). The ionic conductivity of the corresponding gel polymer electrolyte is improved from 2.81 to 3.39 mS cm?1, the discharge capacity retention of the LiCoO2/artificial graphite battery is increased from 95 to 98 % after 100 cycles at 0.5 C, and the discharge capacity of the battery at 1 C increases by 4 %.  相似文献   

6.
Extracts from roots of Beta vulgaris were used as natural sensitizers of a wide-bandgap semiconductor (CeO2–TiO2) in photoelectrochemical solar cells. The natural dye, adsorbed onto the semiconductor surface, absorbs visible light and promotes electron transfer across the dye/semiconductor interface. We have applied CeO2–TiO2 to natural dye sensitizer solar cells as a photoelectrode to reduce the charge recombination rate by providing energy barrier at the interface between the photoanode and electrolyte which offers an improvement of photovoltaic efficiency. Short-circuit current density (J sc) and open-circuit voltages (V oc) of 9.0 mA cm?2 and 680 mV, respectively, were obtained, and an effective energy conversion efficiency of 3.5?% was achieved. This simple and cheap technique of cell preparation opens up a perspective of commercial feasibility for inexpensive and environment-friendly dye cells.  相似文献   

7.
An attempt has been made to fabricate methyl ammonium tin chloride (CH3NH3SnCl3) perovskite-sensitized TiO2 nanostructure photoanode solar cell with hole transport material (HTM) spiro-MeOTAD and graphite-coated counter electrode (CE). The TiO2 nanoparticles (TNPs), TiO2 nanoleaves (TNLs), and TNLs with MgO core/shell photoanodes were prepared to fabricate perovskite-sensitized solar cells (PSSCs). The prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The photovoltaic characteristics of the PSSCs, photocurrent density (J sc), open-circuit voltage (V oc), fill factor (FF), and power conversion efficiency (PCE) were determined under illumination of AM 1.5 G. Electrochemical impedance spectroscopy (EIS) analysis was carried out to study the charge transport and lifetime of charge carriers at the photoanode–sensitizer–electrolyte interface of the PSSCs. The PSSC made with CH3NH3SnCl3 perovskite-sensitized TNL–MgO core/shell photoanode and spiro-MeOTAD HTM shows an impressive photovoltaic performance, with J sc = 17.24 mA/cm2, V oc = 800 mV, FF = 73 %, and PCE = 9.98 % under 100 mW/cm2 light intensity. The advent of such simple solution-processed mesoscopic heterojunction solar cells paves the way to realize low-cost and high-efficiency solar cells. By the aid of electrochemical impedance spectroscopy, it is revealed that the core/shell structure can increase an interfacial resistance of the photoanode–CH3NH3SnCl3 interface and retard an electron recombination process in the photoanode–sensitizer–HTM interface.  相似文献   

8.
Dye-sensitized solar cells (DSSCs) have established themselves as an alternative to conventional solar cells owing to their remarkably high power conversion efficiency, longtime stability and low-cost production. DSSCs composed of a dyed oxide semiconductor photoanode, a redox electrolyte and a counter electrode. In these devices, conversion efficiency is achieved by ultra-fast injection of an electron from a photo excited dye into the conduction band of metal oxide followed by subsequent dye regeneration and holes transportation to the counter electrode. The energy conversion efficiency of DSSC is to be dependent on the morphology and structure of the dye adsorbed metal oxide photoanode. Worldwide considerable efforts of DSSCs have been invested in morphology control of photoanode film, synthesis of stable optical sensitizers and improved ionic conductivity electrolytes. In the present investigation, a new composite nano structured photoanodes were prepared using TiO2 nano tubes (TNTs) with TiO2 nano particles (TNPs). TNPs were synthesized by sol–gel method and TNTs were prepared through an alkali hydrothermal transformation. Working photoanodes were prepared using five pastes of TNTs concentrations of 0, 10, 50, 90, and 100 % with TNPs. The DSSCs were fabricated using Indigo carmine dye as photo sensitizer and PMII (1-propyl-3-methylimmidazolium iodide) ionic liquid as electrolyte. The counter electrode was prepared using Copper sulfide. The structure and morphology of TNPs and TNTs were characterized by X-ray diffraction and electron microscopes (TEM and SEM). The photocurrent efficiency is measured using a solar simulator (100 mW/cm2). The prepared composite TNTs/TNPs photoanode could significantly improve the efficiency of dye-sensitized solar cells owing to its synergic effects, i.e. effective dye adsorption mainly originated from TiO2 nanoparticles and rapid electron transport in one-dimensional TiO2 nanotubes. The results of the present investigation suggested that the DSSC based on 10 % TNTs/TNPs showed better photovoltaic performance than cell made pure TiO2 nanoparticles. The highest energy-conversion efficiency of 2.80 % is achieved by composite TNTs (10 %)/TNPs film, which is 68 % higher than that pure TNPs film and far larger than that formed by bare TNTs film (94 %). The charge transport and charge recombination behaviors of DSSCs were investigated by electrochemical impedance spectra and the results showed that composite TNTs/TNPs film-based cell possessed the lowest transfer resistances and the longest electron lifetime. Hence, it could be concluded that the composite TNTs/TNPs photoanodes facilitate the charge transport and enhancing the efficiencies of DSSCs.  相似文献   

9.
In this work, we have prepared Al-doped TiO2 nanoparticles via a hydrothermal method and used it for making photoanode in dye-sensitized solar cell (DSSC). Material characterizations were done using XRD, AFM, SEM, TEM and EDAX. XPS results reveal that Al is introduced successfully into the structure of TiO2 creating new impurity energy levels in the forbidden gap. This resulted in tuning of the conduction band of TiO2 and reduced charge recombination which led to better current conversion efficiency of DSSC. Greater dye loading and enhanced surface area was obtained for Al-doped TiO2 compared to un-doped TiO2. I-V analysis, EIS and Bode plots are employed to evaluate photovoltaic performance. The short-circuit current density (J sc) and efficiency (η) of cell employing Al-doped TiO2 photoanode were extensively enhanced compared to the cell using un-doped TiO2. The optical band gap (E g) for Al-doped and un-doped TiO2 was obtained as 2.8 and 3.2 eV, respectively. J sc and η were 13.39 mAcm?2 and 4.27%, respectively, under illumination of 100 mWcm?2 light intensity when thin films of 1% Al-doped TiO2 was employed as photoanode in DSSC using N719 as the sensitizer dye. With the use of un-doped TiO2 as photoanode under similar conditions, J sc 5.12 mAcm?2 and η 1.06% only could be obtained. The maximum IPCE% obtained with Al-doped TiO2 and un-doped TiO2 was 67 and 38% respectively at the characteristic wavelength of dye (λ max = 540 nm). The EIS analyses revealed resistive and capacitive elements that provided an insight into various interfacial processes in terms of the charge transport. It was observed that Al-doping reduced the interfacial resistance leading to better charge transport which has improved both photocurrent density and conversion efficiency. Higher electron mobility and fast diffusion resulting in greater charge collection efficiency was obtained for Al-doped TiO2 compared to the un-doped TiO2. Using the Mott–Schottky plot, the donor density was calculated for un-doped and Al-doped TiO2. The work demonstrated that the Al-doped TiO2 is potential photoanode material for low-cost and high-efficiency DSSC.  相似文献   

10.
Low-cost, yellowish, nanocrystalline nitrogen-doped titanium dioxide (N-doped TiO2) powder was synthesized by a hydrothermal method. The as-prepared N-doped TiO2 powder was characterized by X-ray diffraction, transmission electron microscopy (TEM), UV–Vis absorption spectra, X-ray photoelectron spectroscopy (XPS), and Brunauer–Emmett–Teller analysis techniques. The grain size of the prepared powder was around 13 nm as estimated by both Scherrer’s method and TEM images. The effect of the ratio of N-doped TiO2 particles to Degussa P25 on the photovoltaic performance of large-area dye-sensitized solar cells (DSSCs) was also investigated. The N-doped TiO2 electrode showed higher photovoltaic performance compared with that of pure P25 at constant irradiation of 100 mW cm?2, which is attributed to the large pore size and high surface area of N-doped TiO2 resulting in the introduction of extra charge carrier pathways that could be beneficial for overall charge transportation. Energy conversion efficiency of 5.12 % was achieved in a DSSC device with active area of 51.19 cm2.  相似文献   

11.
Polymer gel electrolytes based on poly(acrylic acid)-poly(ethylene glycol) (PAA–PEG) hybrid have been prepared and applied to developed quasi-solid-state dye-sensitized solar cells (DSCs). PAA–PEG hybrid was synthesized by polymerization reaction. Quasi-solid-state DSCs were fabricated with synthesized PAA–PEG electrolyte. The effects of alkali iodides LiI, KI, and I2 concentrations on liquid electrolyte absorbency and ionic conductivity of PAA–PEG were investigated. The evolution of the solar cell parameters with polymer gel electrolyte compositions was revealed. DSCs based on PAA–PEG with optimized KI/I2 concentrations showed better performances than those with optimized LiI/I2 concentrations. The electrochemical impedance spectroscopy technique was employed to examine the electron lifetime in the TiO2 electrode and quantify charge transfer resistances at the TiO2/dye/electrolyte interface and the counter electrode in the solar cells based on the PAA–PEG hybrid gels. A maximum conversion efficiency of 4.96% was obtained for DSCs using KI based quasi-solid electrolyte under 100 mW cm−2. Our work suggests that KI can be the promising alkali metal iodide for improving the performance of PAA–PEG hybrid gel DSCs.  相似文献   

12.
The effect of a gel polymer electrolyte (GPE) as the redox electrolyte used in dye-sensitized solar cells was studied. A GPE solution consisting of 0.5?M sodium iodide, 0.05?M iodine, and ethylene carbonate/propylene carbonate (1:1 w/w) binary solvents was mixed with increasing amounts of styrene–acrylonitrile (SAN). Bulk conductivity measurements show a decreasing trend from 4.54 to 0.83×10?3?S?cm?1 with increasing SAN content. The GPE exhibits Newtonian-like behavior and its viscosity increases from 0.041 to 1.093?Pa?s with increasing SAN content. A balance between conductivity (1.3?×?10?3?S?cm?1) and viscosity (1.4?Pa?s) is observed at 19?wt.% SAN. Fourier transform infrared spectroscopy detects elevated ring torsion at 706?cm?1 upon the addition of SAN into the liquid electrolyte. This indicates that SAN does not bond with the liquid electrolyte. Finally, the potential stability window of 19?wt.% SAN, which ranges from ?1.68 to 1.38?V, proves its applicability in solar cells.  相似文献   

13.
Using poly(acrylonitrile-co-styrene) as polymer host, 1,2-propanediol carbonate, dimethyl carbonate and ethylene carbonate as mixture solvent, N-methyl-quinoline iodide and iodine as the source of I/I3 , a novel polymer gel electrolyte with ionic conductivity of 5.12 × 10−3 S· cm−1 at 25°C was prepared by sol-gel and hydrothermal methods. Based on the polymer gel electrolyte, a quasi-solid-state dye-sensitized solar cell was fabricated. The solar cell possess better long-term stability and light-to-electrical energy conversion efficiency of 4.04% under irradiation of 100 mW· cm−2. The influences of polymer host, solvent, N-methyl-quinoline iodide and temperature on ionic conductivity of the polymer gel electrolyte and the performance of the dye-sensitized solar cell was discussed.  相似文献   

14.
The effect of polypyrrole (PPy) on the polyvinyl alcohol (PVA)-potassium iodide (KI)-iodine (I2) polymer electrolytes has been investigated and optimized to use in a dye-sensitized solar cell (DSSC). The different weight ratios of PVA: PPy (93: 2, 91: 4, 89: 6, 87: 8, and 85: 10 wt%) polymer electrolytes (PE) were prepared by solution casting. Structural, complex formation and surface roughness of the prepared electrolytes was confirmed by X-ray diffraction, FTIR, and atomic force microscopy (AFM) respectively. Conductivity plots of all polymer films showed increasing trend with temperature and concentration of PPy. The activation energy of the optimized system found to be 0.871 kJ mol?1. UV-visible spectrum was adopted to characterize the absorption spectra of the material revealed that increase in the absorbance with increasing PPy content and shifting the absorbance maximum towards lower energy. The indirect band gap decreased from 3.78 to 2.14 eV and direct band gap decreased from 3.88 to 2.71 eV. The EIS analyses revealed the lower charge transfer resistance of 3.029 Ω cm2 at the interface between CE and PE. The excellent performance was observed in the fabricated DSSCs using PVA (85%)/PPy (10%)/KI (5%)/I2 polymer electrolyte with a short-circuit current density of 11.071 mA cm?2, open-circuit voltage of 0.644 V, fill factor of 0.575, and photovoltaic conversion efficiency of 4.09% under the light intensity of 100 mW cm?2. Hence, the PPy content in polymer electrolyte influences the remarkable performance of low-cost DSSC.  相似文献   

15.
This study comes up with the facile preparation of Sr,Zn co-doped TiO2 xerogel film for boosting the short circuit current density of dye-sensitized solar cells (DSCs). The film contains 2.5-μm-diameter spheres assembled from 60 nm nanoparticles. X-ray photoelectron spectroscopy (XPS) shows that Sr2+ and Zn2+ ions to be well incorporated into the TiO2 crystal lattice without forming specific strontium and zinc compositions. The crystallite size, phase composition, and band structure of the spheres depend on the dopants concentration. Isolated energy levels near valence band as a result of the foreign ions introduction improve the photocatalytic activity of the prepared TiO2 spheres, enhancing the short circuit current density of the cells. The DSC co-doped with 0.075 at.% Sr and 0.4 at.% Zn showed the highest power conversion efficiency of 7.87 % and short circuit current density of 18.75 mA cm?2 thanks to lower charge transfer resistance (2.16 Ω cm2), lower electron transit time (1.19 ms), and higher electron diffusion coefficient (18.1 × 104 cm2 S?1) compared to the other cells, demonstrated by electrochemical impedance spectroscopy (EIS). The concept of the simultaneous introduction of alkaline earth ions and transition ions into TiO2 xerogel films will open up a new insight into the fabrication of high performance DSCs.  相似文献   

16.
New quinoxaline-based organic sensitizer bearing di-anchoring group for dye-sensitized solar cells (DSSCs) was synthesized from diethyl 4,5-diaminophthaltate, in which was prepared under mild condition by using Takehito’s method. The synthesized sensitizer was compared with mono-anchoring sensitizer through absorption spectra, emission spectra, J-V curve, and IPCE spectra, indicating the di-anchoring group leads to a noticeable improvement of Jsc value owing to more efficient intramolecular charge transfer and channel number increment.  相似文献   

17.
Comprehensive characterization of new polymer electrolyte system prepared using polyurethane derived from castor oil polyol was undertaken. The castor oil polyol was synthesized via transesterification and reacted with 4,4′-diphenylmethane diisocyanate to form polyurethane. Polyurethane electrolyte films were prepared by addition of sodium iodide in different weight percentage with respect to the weight of the polymer. The electrolyte films were analyzed using Fourier transform infrared spectroscopy, dynamic mechanical analysis, electrochemical impedance spectroscopy, transference number measurement, and linear sweep voltammetry. Fourier transform infrared spectroscopy results confirmed the complexation between polymer and salt. Tan delta peak observed in the tan δ–temperature curve plotted using data obtained from dynamic mechanical analysis indicated that the glass transition temperature of polyurethane decreased with the addition of sodium iodide. The highest conductivity of 4.28 × 10?7 S cm?1 was achieved for the film with 30 wt% of sodium iodide. The performances of dye-sensitized solar cell using the electrolyte systems were analyzed in terms of short-circuit current density, open-circuit voltage, fill factor, and energy conversion efficiency. The polymer electrolyte with 30 wt% sodium iodide showed the best performance with energy conversion efficiency of 0.80%.  相似文献   

18.
The Na/PVdF/S cells were composed of solid sodium, sulfur, and polyvinylidene fluoride–hexafluoropropene (PVdF) gel polymer electrolyte. The PVdF polymer electrolyte was prepared form tetraglyme plasticizer and NaCF3SO3 salt, and its electrochemical properties were studied using CV and impedance analysis. The interfacial resistance between sodium and polymer electrolyte increase with storage time, which might be associated with passivation layer. Solid-state sodium/sulfur cell using a PVdF gel polymer electrolyte has been tested. The Na/PVdF/S cell with 0.288 mA cm?2 shows a high discharge capacity of 392 mAh g?1 and 36 mAh g?1 after 20 cycles. The cycle performance of Na/GPE/S cell operating at 25 °C is worse than Na/S cell at a high temperature.  相似文献   

19.
This study reports the characteristics of gel‐type dye‐sensitized solar cells (DSSCs), fabricated with gel‐type electrolyte containing poly‐1,1′‐(methylenedi‐4,1‐phenylene)bismaleimide (PBMI), or poly‐1,1′‐(3,3′‐dimethyl‐1,1′‐biphenyl‐4,4′‐diyl)bismaleimide (PDBBMI), or poly‐N,N′‐(4‐methyl‐1,3‐phenylene)bismaleimide (PMPBMI), prepared by in situ polymerization of the corresponding monomer without an initiator at 30 °C. Incorporating 0.3 wt % content of exfoliated alkyl‐modified nanomica (EAMNM) into PBMI‐gelled electrolyte leads to higher short‐circuit current density (Jsc = 17.14 mA cm?2) and efficiency (η = 7.02%) than that of neat PBMI‐gel electrolyte (Jsc = 15.32 mA cm?2, η = 6.41%). Incorporating 0.3 wt % EAMNM into PBMI‐gelled electrolyte results in remarkably stable device performance under continuous light soaking under one sun (100 mW cm?2) at 55 °C. The efficiency of DSSCs based on PBMI/0.3 wt % EAMNM‐gelled electrolyte drops by only 1.7% (η = 6.93%) after 500 h of continuous light soaking. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010  相似文献   

20.
Quasi-solid state dye-sensitized solar cells (DSSCs) were assembled by in-situ chemical cross-linking of a gel electrolyte precursor containing liquid electrolyte. The DSSCs assembled with this cross-linked gel polymer electrolyte showed higher open circuit voltage and lower short-circuit photocurrent density than those of DSSCs with liquid electrolyte. Addition of SiO2 nanoparticles into the cross-linked gel polymer electrolyte significantly improved the photovoltaic performance and long-term stability of the DSSCs. The optimized quasi-solid state DSSC showed high conversion efficiency, 6.2% at 100 mW cm?2 with good durability.  相似文献   

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