Typical Dye-sensitized Solar Cells Research Articles

From reflection to absorption: Improving light harvesting of dye sensitized solar cells with Cu nanowires as reflectors

Back reflectors have emerged as an effective approach to improve the light harvesting ability of photoanodes, which is considered as an obstacle to high performing photovoltaic (PV) devices. Considering the light scattering phenomenon of one dimensional (1D) material playing significant role in back-reflection, the present work demonstrated the use of 1D copper nanowires (Cu NWs) as light reflectors in dye sensitized solar cells (DSSCs) towards improving their PV performance. Cu NWs were synthesized using solvothermal method and characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDX) mapping. The criteria behind using Cu NWs reflectors is to utilize the unabsorbed incident light, which is usually transmitted through the platinum (Pt) counter electrode (CE) in a typical DSSC, to enhance the light harvesting ability of photoanodes and hence their PV performance. We have observed a 10.2% enhancement in the power conversion efficiency (PCE) of Cu reflector based DSSCs (6.69%) relative to reference DSSCs (6.07%). The improved PV performance of Cu reflector based DSSCs is supported by the reduced charge transfer resistances at different interfacial layers obtained from the electrochemical impedance spectroscopy (EIS) measurements. By demonstrating the remarkable cost-effectiveness of Cu NWs, our findings pave the way for the widespread implementation of reflectors in next-generation photovoltaic devices, enabling enhanced performance across diverse environmental settings.

Recent Advances on Pt-Free Electro-Catalysts for Dye-Sensitized Solar Cells.

Since Prof. Grätzel and co-workers achieved breakthrough progress on dye-sensitized solar cells (DSSCs) in 1991, DSSCs have been extensively investigated and wildly developed as a potential renewable power source in the last two decades due to their low cost, low energy-intensive processing, and high roll-to-roll compatibility. During this period, the highest efficiency recorded for DSSC under ideal solar light (AM 1.5G, 100 mW cm−2) has increased from ~7% to ~14.3%. For the practical use of solar cells, the performance of photovoltaic devices in several conditions with weak light irradiation (e.g., indoor) or various light incident angles are also an important item. Accordingly, DSSCs exhibit high competitiveness in solar cell markets because their performances are less affected by the light intensity and are less sensitive to the light incident angle. However, the most used catalyst in the counter electrode (CE) of a typical DSSC is platinum (Pt), which is an expensive noble metal and is rare on earth. To further reduce the cost of the fabrication of DSSCs on the industrial scale, it is better to develop Pt-free electro-catalysts for the CEs of DSSCs, such as transition metallic compounds, conducting polymers, carbonaceous materials, and their composites. In this article, we will provide a short review on the Pt-free electro-catalyst CEs of DSSCs with superior cell compared to Pt CEs; additionally, those selected reports were published within the past 5 years.

Facile synthesis of cobalt–nickel sulfide thin film as a promising counter electrode for triiodide reduction in dye-sensitized solar cells

In typical dye-sensitized solar cells, platinum metal-based counter electrode is employed to collect electrons from the external circuit and catalyze the triiodide (I3⁻) reduction in the electrolyte. However, due to the high cost of platinum, development of inexpensive material based counter electrodes is highly desirable to lower the cost of production of the devices. Herein, we report a facile strategy to deposit a cobalt-nickel sulfide nanostructured thin film showing promising electrocatalytic characteristics, as a low-cost counter electrode material. A simple one-step solution-based fabrication method for the binder-free cobalt-nickel sulfide counter electrode at low-temperature is one of the key features of this work. The as-deposited cobalt-nickel sulfide film is highly crystalline even without thermal treatment. The results demonstrate that the as-obtained cobalt-nickel sulfide thin film on a conductive substrate can be employed as a counter electrode directly in a dye-sensitized solar cell. Cyclic voltammetry, Tafel plot and electrochemical impedance spectroscopy show that the as-synthesized cobalt-nickel sulfide counter electrode exhibits an excellent electrocatalytic property competing with the state-of-the-art platinum counter electrode. As a result, the dye-sensitized solar cell based on the cobalt-nickel sulfide counter electrode yields the best power conversion efficiency of 8.86%, which closely matches the performance of the dye-sensitized solar cell based on a platinum counter electrode (9.08%). The excellent electrocatalytic property obtained from the low cost and simple synthesis process could render the cobalt-nickel sulfide nanostructure standing out as a competitive alternative to the expensive platinum counter electrode. As such, this work overlays a path for the rational design of inexpensive, and so far achieved highly-efficient cobalt-nickel sulfide counter electrode for the advanced energy applications.

“Paper Dye-Sensitized Solar Cell” Based on Carbon-Nanotube-Composite Papers

We propose a paper solar cell based on carbon nanotube (CNT)-composite papers. To fabricate this cell, we use dye-sensitized solar cells (DSCs) for generating power through the redox reaction of dyes in conjunction with CNT-composite papers, which are composite materials containing CNTs and pulp (raw paper material) that can be fabricated easily by using a method based on the Japanese washi papermaking technique. The demand for CNT applications is expected to increase due to their high conductivity and metallic or semiconducting characteristics. This CNT-composite paper can also have metallic or semiconducting characteristics based on the contained CNTs in the composite paper. We previously fabricated a DSC that generates electricity by using CNT-composite papers stacked in a typical DSC structure. However, the conversion efficiency of this DSC was just 0.188%, which is not practical. To overcome this low power generation issue, we tried improving the DSC structure by applying electrodes to the CNT-composite papers in grid patterns for efficient current collection and applying an optimally mixed dye for efficient electron excitation. Results showed that the conversion efficiency improved to 0.58%. Moreover, we demonstrated that using a mixed dye can improve the conversion efficiency of the paper DSC. We expect these types of CNT-composite papers to be used as material for new DSCs.

Stability of the oxidized form of RuLL′(NCS)2 dyes in acetonitrile in the presence of water and pyridines – Why the dye-sensitized solar cell electrolyte should be dry

The detrimental effect of electrolyte water contamination on the light-soaking lifetime of Dye-sensitized Solar Cells (DSCs) prepared with RuLL′(NCS)2 dyes and N-additives like 4-tert-butylpyridine (TBP) is not well understood. A new explanation is presented based on investigation of the stability of the ruthenium(III) complexes Ru(bipy)2(NCS)2+ (1+) and RuLL′(NCS)2+ (L = 4,4′-dicarboxy-2,2′-bipyridine, L′= 4,4′-nonyl-2,2′-bipyridine) (Z907+) in acetonitrile in the presence of water and pyridines covering a large variation in basicity. 1+ reacts with small amounts of water in the acetonitrile containing a pyridine base (X) according to the overall reaction: 6Ru(bipy)2(NCS)2+ + 4H2O + 8X → 5Ru(bipy)2(NCS)2 + Ru(bipy)2(NCS)(CN) + SO42− + 8XH+. The reaction mechanism of 1+ (and Z907+) is proposed to be initiated by an attack of OH− giving Ru(bipy)2(NCS)(NCS-OH). The stronger the base the faster the reaction. Extrapolating the life time of Z907+ to a typical TBP concentration of 0.5 M in the DSC gives a degradation rate around 7 s−1. Z907+ bound to a layer of nano crystalline TiO2 surface reacted fast too, when inserted in an acetonitrile solution containing 4-tert-butylpyridine. In a “wet” electrolyte, containing more than 500 mM of water the light-soaking lifetime of a DSC prepared with Z907 is predicted to be about 10 days at out-door light soaking conditions, whereas trace amounts of water (<25 mM) in a “dry” electrolyte is used up by consumption of only 10% of the Z907 in a typical DSC. Therefore, the DSC is expected to have a long light-soaking lifetime with a “dry” electrolyte.

Influence of different solvents on the electrical properties of dye-sensitized solar cells

Since their discovery, dye-sensitized solar cells (DSSCs) have gained huge interest of many researchers. While still showing lower efficiencies than common silicon-based solar cells, they have the advantage of being produced by low-cost, low-toxic materials outside a clean room. This is why a large number of research groups concentrate on developing new materials for all layers of a typical DSSC to gain higher efficiencies and increase longevity. Specifically, the dye has been shown to significantly influence the DSSC performance. Here, we report on the impact of different low-cost, low-toxic solvents—acetone, ethanol, isopropanol, and dimethyl-sulfoxide, applied purely or in combination with water in different ratios—on the resulting DSSC performance, using two anthocyanin-based dyes. We found ethanol and dimethyl-sulfoxide to result in the highest efficiencies of the final DSSCs.

Prussian blue-derived synthesis of uniform nanoflakes-assembled NiS2 hierarchical microspheres as highly efficient electrocatalysts in dye-sensitized solar cells.

It's urgent and challenging to explore cost-effective and robust electrocatalyst in the development of large-scaled dye-sensitized solar cells (DSSCs). In this work, we develop a novel strategy to prepare 3D hierarchical NiS2 microspheres constructed by nanoflakes through a facile chemical etching/anion exchange reaction. Nickel–cobalt Prussian blue analogous (PBA) nanocubes and (NH4)2S are employed to initially produce uniform γ-NiOOH/NiSx hierarchical microspheres, which were then converted to uniform 3D hierarchical NiS2 microspheres by a controlled annealing treatment. Due to their favorable structural features, the as-obtained NiS2 hierarchical microspheres possess large surface areas, high structural void porosity and accessible inner surface. All of these advantages facilitate the mass diffusion and charge transport between electrolyte and counter electrode material. As a result, the titled NiS2 hierarchical microspheres exhibit excellent electrocatalytic activity toward the reduction of I3− ions in DSSCs. A typical DSSC with NiS2 achieves an impressive power conversion efficiency of 8.46% under AM1.5G illumination (100 mW cm−2), higher than that of pyrolysis Pt electrodes (8.04%). Moreover, the fast activity onset and relatively long stability further demonstrate that the NiS2 hierarchical microspheres are promising alternatives to Pt in DSSCs.

Hysteresis analysis in dye-sensitized solar cells based on external bias field effects

The current density-voltage (J–V) hysteresis phenomenon occurs in perovskite solar cells as well as dye-sensitized solar cells (DSCs); however, it has received little attention in DSCs. We consider that the trapping–detrapping-induced variation of the charge collection efficiency might cause J–V hysteresis. Therefore, we conduct a systematic study on the influence of an external bias field during and before J–V measurements in typical DSCs. We find that the J–V performance of DSCs significantly depends on the scan bias direction and the external bias field before and during measurements. Our results indicate that the external-bias-field-modulated charge injection, trapping–detrapping, and accumulation processes in DSCs are possible causes for the anomalous J–V behavior.

Modeling of interfacial and bulk charge transfer in dye-sensitized solar cells

AbstractA simple, first-principles mathematical model has been developed to analyze the effect of interfacial and bulk charge transfer on the power output characteristics of dye-sensitized solar cells (DSSCs). Under steady state operating conditions, the Butler-Volmer equation and Schottky barrier model were applied to evaluate the voltage loss at counter electrode/electrolyte and TiO2/TCO interfaces, respectively. Experimental data acquired from typical DSSCs tested in our laboratory have been used to validate the theoretical J–V characteristics predicted by the present model. Compared to the conventional diffusion model, the present model fitted the experimental J–V curve more accurately at high voltages (0.65–0.8 V). Parametric studies were conducted to analyze the effect of series resistance, shunt resistance, interfacial overpotential, as well as difference between the conduction band and formal redox potentials on DSSCs’ performance. Simulated results show that a “lower-limit” of shunt resistance (1...

Pristine and Al-doped hematite printed films as photoanodes of p-type dye-sensitized solar cells

We hereby propose a non-expensive method for the deposition of pure and Al-doped hematite photoanodes in the configuration of thin films for the application of dye-sensitized solar cells (DSSC). The electrodes have been prepared from hematite nanoparticles that were obtained by thermal degradation of a chemical precursor. The particles have been used in the preparation of a paste, suitable for both screen printing and doctor blade deposition. The paste was then spread on fluorine-doped tin oxide (FTO) to obtain porous hematite electrodes. The electrodes have been sensitized using N3 and D5 dyes and were characterized through current/voltage curves under simulated sun light (1 sun, AM 1.5) with a Pt counter electrode. Al-doping of hematite showed interesting changes in the physical and electrochemical characteristics of sensitized photoanodes since we could notice the growth of AlFe2O4 (hercynite) as a secondary crystal phase into the oxides obtained by firing the mixtures of two chemical precursors at different molar ratios. Pure and Al-doped hematite electrodes have been used in a complete n-type DSSCs. The kinetics of charge transfer through the interface dye/electrolyte was studied and compared to that of a typical p-type DSSC based on NiO photocathodes sensitized with erythrosine B. The results suggest a potential application of both Fe2O3 and Fe2O3/AlFe2O4 as photoanodes of a tandem DSSC.

Fabrication of TiO2 Based Microspheres By Spray Drying Method and Their Application for Dye-Sensitized Solar Cells

Dye-sensitized solar cells (DSSCs) have received considerable attention since Grätzel et.al.reported a high conversion efficiency using nanocrystalline mesoporous TiO2 film. A typical DSSC consists of a transparent conductive oxide, semiconductor oxide, dye sensitizer, electrolyte and counter electrode. The working electrode is a nanoporous semiconductor oxide that is placed on conducting glass and is separated from the counter electrode by only a thin layer of electrolyte solution. The photoanode of DSSCs is typically constructed using a thick film (~20 μm) of TiO2 or, less often, ZnO or SnO2 nanoparticles. The TiO2 film has a large inherent absorptive surface area for light scattering. Recently, TiO2 microspheres are of great interest for a great deal of applications, especially in the solar cell field. Because of their unique microstructure and light-scattering effect, TiO2 microsphere-based solar cells often exhibit superior photovoltaic performance. Hence, exploring new suitable TiO2 microspheres for high-efficiency solar cells is essential. In this study, we reported the fabrication of TiO2microspheres by a simple spray drying process, and applied for Dye-sensitized Solar Cells. TiO2 Microspheres were fabricated by spray drying method. TiO2 paste was prepared as follows, TiO2 microspheres (0.2g) was mixed into ethanol (1.8g). The resulting TiO2 paste was printed by doctor blade method on fluorine-doped SnO2-coated (FTO) glass electrodes and sintered at 500 °C for 30 min. DSSCs were prepared by a conventional procedure. We are successfully fabricated TiO2 microspheres by spray drying method. According to SEM images of the TiO2 microspheres, particle size was ca. 3mm. We made microsphere TiO2 based DSSCs, and their energy conversion efficiency was 6.5% under AM 1.5 simulated full sunlight (100 mW cm−2) illumination.

Preparation of NiCo2S4 Thin Films As Counter Electrodes for Dye-Sensitized Solar Cells Using Dip-Coating Method

Dye-sensitized solar cells (DSCs) have attracted intensive attention due to its high efficiency, low cost, and easy fabrication process. The main components of a typical DSC include a photo anode, an I−/I3 − redox electrolyte and a Pt counter electrode (CE). To speed up the commercialization of DSCs, the manufacturing cost of DSCs should be further significantly reduced. Both of exploring alternative CE materials to noble Pt and developing facile and low-cost fabrication process of CEs are crucial for achieving this purpose. In this study, NiCo2S4 (NCS) counter electrodes (CEs) were successfully fabricated via a facile dip-coating method for the first time. Prior to the CE preparation, the NCS particles were synthesized via a hydrothermal method. Afterward, the as-synthesized NCS were ball milled and then dispersed in de-ionized water or ethanol solutions. The bare fluorine-doped tin oxide (FTO) glass substrates were dipped in the surface-conditioner solution for 1 min and subsequently dipped in the as-prepared NSC suspension solution for different times. The Inductively Coupled Plasma Mass Spectrometry (ICP-MS) results showed the mass loadings for both kinds of NCS CEs first increased with immersion time, and then retain almost the same while the immersion time was over than 10 min The NCS CEs prepared by dipping in de-ionized water solutions for 10 min is designated as NCS CE. According to the electrochemical and photovoltaic measurements, NCS CE demonstrated superior electrocatalytic activity. Moreover, NCS showed the low charge-transfer resistance of 1.56 Ω. As a result, the photovoltaic conversion efficiency of the DSC based on the NCS CE was up to 7.36%, significantly higher than the Pt CE (7.29%).

Surface plasmon resonance enhanced multi-shell-modified upconversion NaYF4:Yb3+, Er3+@SiO2@Au@TiO2 crystallites for dye-sensitized solar cells

Both upconversion of near-infrared light and surface plasmon resonance (SPR) of nobel metal nanoparticles (NPs) show potential application in dye-sensitized solar cells(DSSCs). For the first time, the novel multi-shell-coated and Au-NPs decorated hexagonal submicron β-NaYF4:Yb3+, Er3+(NFYE)@SiO2@Au@TiO2(NSAT) prisms were prepared and incorporated into the photoanodes of DSSCs. The influences of different coating layers and decorated Au-NPs on the upconversion of NFYE and the performance of DSSCs were comparatively investigated. Studies indicated that the coated multi-shells have great influences on the upconversion and the properties of DSSCs. The Au-NPs can remarkably enhance the intensity of upconversion luminous emission and thus the short-circuit current density (Jsc) and photoelectron conversion efficiency (η) of the DSSCs. The TiO2 shell is beneficial for absorbing more dye and lowering the interface transport resistance. The optimal Jsc and η obtained in a typical DSSC containing NSAT are 18.62 mA/cm2 and 7.79%, respectively, corresponding 38.2% and 28.1% higher than that of the DSSC with a pure TiO2 photoanode. This significant improvement can be mainly attributed to the enhanced upconversion emission of the NSAT prisms arising from the SPR effect of the embeded Au-NPs and to the possible enhanced scattering from the submicron prisms.

Dye Sensitized Solar Cells with Low Cost Carbon Nanotubes Electrodes

Dye sensitized solar cells (DSSCs) are very sensitive to electrodes, due to either high cost or easy corrosion problems. To minimize these factors, we present DSSCs with cheap carbon nanotubes as counter electrodes. In addition, we suggest replacing the electrolyte (in typical DSSCs) with a solid film of powdered CsSnI3. The electrical behavior (I-Vcharacteristics) of the proposed device has been measured for different shading conditions. In the light of a theoretical model based on the presence of two diodes, the experimental data have been explained, taking into account a new equivalent circuit for the DSSC. These DSSCs may receive different levels of sun radiation, which stimulates the study of partial shading; so, we have studied the effect of different shadow rates on the solar conversion efficiency of a unit of 4-W-connected DSSCs. The validity of the present model has been examined by fitting it intoI-Vcharacteristics at different shading rates.

Recent Development of Graphene-Based Cathode Materials for Dye-Sensitized Solar Cells

Dye-sensitized solar cells (DSSCs) have attracted extensive attention for serving as potential low-cost alternatives to silicon-based solar cells. As a vital role of a typical DSSC, the counter electrode (CE) is generally employed to collect electrons via the external circuit and speed up the reduction reaction ofI3-toI-in the redox electrolyte. The noble Pt is usually deposited on a conductive glass substrate as CE material due to its excellent electrical conductivity, electrocatalytic activity, and electrochemical stability. To achieve cost-efficient DSSCs, reasonable efforts have been made to explore Pt-free alternatives. Recently, the graphene-based CEs have been intensively investigated to replace the high-cost noble Pt CE. In this paper, we provided an overview of studies on the electrochemical and photovoltaic characteristics of graphene-based CEs, including graphene, graphene/Pt, graphene/carbon materials, graphene/conducting polymers, and graphene/inorganic compounds. We also summarize the design and advantages of each graphene-based material and provide the possible directions for designing new graphene-based catalysts in future research for high-performance and low-cost DSSCs.

Metal-based bracken-like single-sided dye-sensitized solar cells with horizontal separation.

One of the drawbacks of typical dye-sensitized solar cells (DSCs) is their high cost and the high electrical resistance of the transparent conducting substrate. In conventional sandwich-type DSCs, only one of the FTO substrates can be replaced by a metal substrate. We investigated an all-metal-electrode single-sided DSC in which interpenetrated bracken-like Cr electrodes were created using photolithography; mesoporous TiO2 and Pt films were deposited on the laterally separated electrodes. Thermal Pt deposition and electrodeposition methods were investigated and it was found that a cyclic electrodeposition method resulted in selective Pt deposition at room temperature with a higher device performance. Cu or ZnO sacrificial layers and TiO2 or TiO2/SiO2 porous layers were used for the spacer layer that keeps the Pt electrode away from the TiO2 mesoporous layer and the optimum results were obtained when a TiO2/SiO2 layer was used. The best device had a current density of 8.47 mA cm(-2), an open circuit voltage of 0.685 V and an efficiency of 2.44%. The results of open circuit voltage decay and electrochemical impedance spectrometry showed the formation of a high-resistivity blocking layer, which was attributed to the Cr oxide formed during thermal treatment. The efficiency may be improved further by developing low-temperature fabrication processes.

Possibility of NCS Group Anchor for Ru Dye Adsorption to Anatase TiO2(101) Surface: A Density Functional Theory Investigation

We examined the possibility of the presence of isothiocyanate (NCS) group anchor for Ru dye adsorption to anatase TiO2(101) surface in typical dye-sensitized solar cells (DSCs), motivated by the recent X-ray photoelectron spectroscopy (XPS) experimental observations of the NCS anchors. A variety of adsorption configurations were examined with model molecules of CH3NCS by density functional theory (DFT) calculations. To compare with the experimental XPS spectra, we also calculated core–electron binding energies using (TiO2)38 cluster model. We demonstrated that 0.6–0.7 eV of the observed chemical shift in the S 2p XPS spectra can be assigned to the S interactions with the surface Ti atom and O vacancy, while 8.8 eV shift in the S 1s level is connected to the S–Ti vacancy interaction. On the other hand, it is also confirmed that the adsorption energies of COOH group and acetonitrile solvent molecule are usually larger than that for the NCS group. Therefore, the Ru dye adsorption through the NCS anchor is less probable even on the surface in vacuum and further decreases in the solution environment. With these results, we conclude that the NCS group anchoring is possible in the vacuum environment as shown by the XPS studies, while it will be negligible on the working electrode of the solar cell.

Pt-free counter electrode for dye-sensitized solar cells with high efficiency.

Dye-sensitized solar cells (DSSCs) have attracted widespread attention in recent years as potential cost-effective alternatives to silicon-based and thin-film solar cells. Within typical DSSCs, the counter electrode (CE) is vital to collect electrons from the external circuit and catalyze the I3- reduction in the electrolyte. Careful design of the CEs can improve the catalytic activity and chemical stability associated with the liquid redox electrolyte used in most cells. In this Progress Report, advances made by our groups in the development of CEs for DSSCs are reviewed, highlighting important contributions that promise low-cost, efficient, and robust DSSC systems. Specifically, we focus on the design of novel Pt-free CE catalytic materials, including design ideas, fabrication approaches, characterization techniques, first-principle density functional theory (DFT) calculations, ab-initio Car-Parrinello molecular dynamics (CPMD) simulations, and stability evaluations, that serve as practical alternatives to conventional noble metal Pt electrodes. We stress the merits and demerits of well-designed Pt-free CEs, such as carbon materials, conductive polymers, transition metal compounds (TMCs) and their corresponding hybrids. Also, the prospects and challenges of alternative Pt catalysts for their applications in new-type DSSCs and other catalytic fields are discussed.

Sulfide Modification of Dye-Sensitized Solar Cell Gold Cathodes for Use with Cobalt Polypyridyl Mediators

[Co(bpy)3]2+/3+-type complexes have emerged as promising alternatives to the traditional I–/I3– electrolyte used in dye-sensitized solar cells (DSSCs). One of the many advantages these complexes exhibit is their ability to undergo reduction on Au cathodes rather than the more expensive Pt. However, in our experience irreproducibility of fabricated Au cathodes has been a longstanding issue due to variations in charge-transfer resistance (RCT) for the Co2+/3+ couple. These variations manifest themselves as poor fill factors in the current–voltage measurements. In an effort to increase electronic coupling between the Co complex and the Au surface (and thereby reduce RCT), a simple surface modification with sulfide ion has been developed. XPS measurements indicate the modification is stable after exposure to mediator solution. Cyclic voltammetry shows a drastic increase in reversibility for the Co2+/3+ electrochemistry, especially under typical DSSC mediator conditions. A commensurate enhancement in the fill factor is observed in subsequent J–V measurements. The results provide a straightforward method of yielding more reproducible Au cathodes to be used in combination with [Co(bpy)3]2+/3+-type mediators.

Modification of dye-sensitized solar cell working electrode using TiO2 nanoparticle/N-doped TiO2 nanofiber composites

Nanocomposite films of N-doped TiO2 nanofibers (NFs) and commercial-grade TiO2 nanoparticles Degussa (P25) were utilized as working electrode of typical dye-sensitized solar cells (DSSCs). N-doped TiO2 NFs were fabricated via electrospinning method using ammonium acetate (CH3COONH4) as nitrogen source and titanium (IV) isopropoxide (TiP) in ethanol as starting precursor in combination with calcinations process. The electrospun NFs were characterized by XRD, Raman spectroscopy, XPS, SEM, and TEM. The photoelectric conversion performance of the DSSCs with composite film electrode was compared to the device using pure P25 film. The result shows that as calcination temperature increases, the anatase-to-rutile phase transformation and the fiber size reduction of NFs were observed. The energy conversion efficiency (η) of the device tends to increase with increasing calcined temperature with specific nanofiber loading content, indicating the significant enhancement in the device performance by the incorporation of the NFs. This enhancement of DSSCs may attribute to high surface area, higher light scattering and light harvesting, low charge recombination, and fast electron-transfer rate by loaded NFs.