Energy Conversion Efficiency Of Dye-sensitized Solar Cells Research Articles

Performance test of Zn-astaxanthin complex-sensitized solar cell: effect of light intensity on open-circuit voltage and short-circuit current values.

The sensitizer is one of the most essential dye-sensitized solar cell (DSSC) components. In the present research, a Zn-astaxanthin complex was investigated as a sensitizer, compared to pure astaxanthin. The complex with a 1:1 mole ratio between astaxanthin and Zn2+ was synthesized in a reflux reactor at 37-60 °C. The product was analyzed using Proton Nuclear Resonance (1H-NMR), which indicates the presence of chelate formation between Zn2+ with two atoms of oxygen on the terminal cyclohexane ring of astaxanthin. The interaction of sensitizers (astaxanthin and Zn-astaxanthin) on the photoelectrode surface in this study was analyzed using a Fourier Transform Infra-Red (FTIR) and Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS). The FTIR spectra of photoelectrode immersed in Zn-astaxanthin show peaks of C=O stretching and vibration -OH group at 1730 and 1273 cm-1, respectively, and H-C-H stretching vibration with high intensity in 2939, 2923, and 2853 cm-1. The UV-Vis DRS analysis shows the band gap of photoelectrode (PE), photoelectrode immersed in astaxanthin (PE/astaxanthin), and Zn-astaxanthin (PE/Zn-astaxanthin) are 3.19, 1.65, and 1.59 eV, respectively. Under illumination intensity of 300 W/m2, the maximum energy conversion efficiency of DSSC with Zn-astaxanthin as sensitizer is (0.03 ± 0.0022)%, higher than DSSC with astaxanthin as sensitizer ((0.12 ± 0.0052)%). Up to 70 h of illumination, DSSC with Zn-astaxanthin as a sensitizer also has better stability than astaxanthin-based DSSC.

Combined experimental and DFT investigation on photovoltaic performance of low-cost metal-free organic dye-sensitized solar cells

Metal-free organic dyes, viz. eosin yellow (eosin-Y), fluorescein and curcumin were used as sensitizers in zinc oxide (ZnO) nanoparticles thin film photoanode based dye-sensitized solar cell (DSSC) and also investigated by density functional theory (DFT). UV–vis spectrophotometer was employed to determine absorption feature of dyes in solar spectrum, adsorption tendency towards ZnO photoanode surface, molar-extinction coefficient and desorbed dye molecules from the photoanode surface. The photovoltaic performance of metal-free organic DSSCs employing imidazole based liquid electrolyte and platinum counter electrode was evaluated under standard light exposure of 85 mW/cm2. Among the dyes, eosin-Y DSSC delivered overall energy conversion efficiency (η) of 0.95 % with short-circuit photocurrent density (Jsc) of 2.98 mA cm−2, open-circuit photovoltage (Voc) of 0.54 V and fill factor (FF) of 0.50, which was about 20 % and 40 % higher than that of the energy conversion efficiency of DSSCs sensitized with fluorescein and curcumin dyes, respectively. The better photovoltaic performance exhibited by the eosin-Y DSSC is credited to its high molar extinction coefficient, intense light absorption in the solar spectrum and good adsorption on ZnO thin film photoanode surface. The maximum driving force for dye molecules regeneration and electron injection value of eosin-Y dye attached on the surface of ZnO cluster (eosin-Y + ZnO) resulted in higher Voc. The outcomes of this experimental data are in well agreement with DFT results.

A roadmap for hydrogel-based quasi-solid electrolyte preparation for use in dye-sensitized solar cell

Although the use of quasi-solid electrolytes in dye-sensitized solar cells (DSSCs) is viewed as a solution to the stability problem of DSSCs, the network structure effect on the DSSCs’ performance has not been studied in detail. Structurally different hydrogels poly (2-methacryloyloxyethyl trimethylammonium chloride-co-acrylic acid) were prepared and used as quasi-solid gel electrolytes in DSSCs to investigate the network structure effect of hydrogels on DSSC performance. The hydrogel's network structure was changed using different amounts of cross-linkers during synthesis. Five quasi-solid electrolytes were prepared from the hydrogels. The increased cross-linking of quasi-solid electrolytes during synthesis raised conductivity from 0.102 to 0.144 S m−1. Despite expectations, it was observed that the energy conversion efficiency of DSSCs does not follow the rising trend in conductivity, as it rises from 6.57% to 6.62% and then decreases to 5.17%, with increased cross-linking. Moreover, cross-linking during hydrogel synthesis defines not only the electrical properties of quasi-solid electrolytes but also the swelling, wetting, and morphological properties of the structure. Therefore, this study aimed to investigate how and which parameters affect the energy conversion efficiency of DSSCs that are prepared with quasi-solid electrolytes.

TiO2 treatment using ultrasonication for bubble cavitation generation and efficiency assessment of a dye-sensitized solar cell

In this study, the impacts of different ultrasonic treatments on TiO2 particles were determined and they were used to manufacture the photoelectrodes of a dye-sensitized solar cell (DSSC). Two methods were used to prepare TiO2 particles directly sonicated by an ultrasonic horn, and TiO2 treated indirectly by an ultrasonic cleaner. TEM, XPS analysis was confirmed that cavitation bubbles generated during ultrasonication resulted in defects on the surface of TiO2 particles, and the defect induced surface activation. To understand the effect of TiO2 surface activation on energy conversion efficiency of DSSC, ultrasonic horn DSSC and ultrasonic cleaner DSSC were prepared. The UV–vis analysis exhibited that the ultrasonic horn DSSC possessed higher dye adsorption when compared to the ultrasonic cleaner DSSC, and the EIS analysis confirmed that the electron mobility was greatly increased in the ultrasonic horn DSSC. The energy conversion efficiency of the ultrasonic horn DSSC was measured to be 3.35%, which is about 45% increase in comparison to that of the non-ultrasonic treated DSSC (2.35%). In addition to this regard, recombination resistance of ultrasonic horn DSSC was calculated to be 450 Ω·cm2, increasing more than two times compared to the non-ultrasonic treated DSSC (200 Ω·cm2). Taken together, these ultrasonic treatments significantly improved the energy conversion efficiency of DSSC, which was not tried in DSSC-related research, and might lead us to develop more efficient practical route in the manufacturing of DSSC.

Investigation on the role of graphene oxide sheet-platinum composite counter electrode in dye-sensitized solar cell

Graphene oxide's advantages compared to other materials, such as catalytic potential in electronic fields, led to an investigation of graphene oxide sheets (GS) in dye-sensitized solar cells (DSSC) with respect to energy conversion efficiency (%), open-circuit photovoltage, short-circuit photocurrent density, and fill factor. The different concentrations of GS were synthesized with a Pt precursor and the effects of GS-Pt composite were examined for use as counter electrodes. The energy conversion efficiency of DSSCs with GS-Pt composites enhanced performance up to 6.60% when 0.01 wt% GS was applied on counter electrodes. In addition, we found that GS increases (111) the crystallinity of Pt as well as surface area, allowing catalytically active sites for tri-iodide reduction.

Performance Improvements of Bixin and Metal-Bixin Complexes Sensitized Solar Cells by 1-Methyl-3-propylimidazolium Iodide in Electrolyte System

Bixin is one of the potential natural sensitizers used in dye-sensitized solar cells (DSSCs). In this study, bixin was complexed with Cu(II) and Zn(II) to increase its stability. The formation of the complexes was indicated by shifting peaks absorption and the changes in the fine spectral structure observed from the UV-Vis absorption spectra. The metal-bixin complex occurs due to the interaction between the ester groups of bixin and the metal. Bixin, Cu-bixin, and Zn-bixin were used separately as sensitizers in DSSCs. The DSSCs performance was then improved by adding 1-methyl-3-propylimidazolium iodide (MPII) to the electrolyte system. The presence of MPII 0.4 M in KI-I2 electrolyte produced a higher ionic conductivity value (20.44 mS cm–1) than that without MPII (11.14 mS cm–1). This electrolyte system significantly improved DSSCs performance. Under a light intensity of 300 W/m2, the maximum energy conversion efficiencies of DSSC with bixin, Cu-bixin, and Zn-bixin as sensitizers are 0.084, 0.081, and 0.005%, respectively. The Zn-bixin-based DSSC was stable under high light intensity. Under 700 W/m2, its maximum energy conversion efficiency reaches 0.125%. There was a synergistic work observed between the metal-bixin complex and the MPII based electrolyte. This result can open the way for constructing functional materials for solar cell applications.

Improved photovoltaic performance of dye-sensitized solar cells by Au-ion implantation of titania film electrodes

Plasmonic metal nanoparticles are known to work as light-harvesting antennae and to enhance photocurrents of photovoltaic cells. Therefore, in this work, the effect of gold (Au) ions distribution on the efficiency of dye sensitized solar cells (DSSCs) has been investigated. Thin films of TiO2 have been deposited on FTO glass substrates by the doctor tape method. Au ions were then implanted on these films with different fluence rates (i.e., 2 × 1014, 4 × 1014 and 6 × 1014 ions/cm2). XRD results confirmed that TiO2 is present in the anatase phase up to a 4 × 104 ions/cm2 fluence rate. At a 6 × 1014 ions/cm2 fluence rate, one peak of rutile is obtained which confirmed that the film has mixed phases of TiO2. UV results show that dye is adsorbed into all photoanodes. Maximum dye absorption is seen at a fluence rate of 4 × 1014 ions/cm2. The energy conversion efficiency of DSSC is highly dependent on the fluence rate of Au. At a fluence rate of 4 × 1014 ions/cm2, the cell has a high short circuit current density (JSC) of 7.21 mA/cm2, resulting in a high efficiency (×) of 2.92%. Impedance spectroscopy shows that the cell formed by Au ions fluence rate of 4 × 1014 ions/cm2 has a low recombination rate of electron/hole pairs.

Facile Synthesis of CoNi Bimetallic Nanoparticle Decorated Reduced Graphene Oxide as Efficient and Low-Cost Counter Electrode for Dye-Sensitized Solar Cells.

In this paper, CoNi bimetallic nanoparticle decorated reduced graphene oxide (CoNi-RGO) was synthesized by a facile hydrothermal method. When applied this CoNi-RGO into counter electrode for dye-sensitized solar cells (DSSCs), it shows smaller charge-transfer resistance and better electrocatalytic activity than that of pure reduced graphene oxide (RGO). At the optimized conditions, the energy conversion efficiency of DSSCs based on CoNi-RGO counter electrode was 3.79%, indicating a higher photovoltaic performance of DSSCs based on CoNi-RGO counter electrode than that of DSSCs based on RGO counter electrode (1.37%), and comparable to the value of DSSCs based on Pt counter electrode as a reference (4.95%). Additionally, the photovoltaic performance of DSSCs based on CoNi-RGO counter electrode strongly depends on its composition. The molar ratio of Co/Ni and the weight ratio of CoNi/GO that used to prepare CoNi-RGO counter electrode are key factors to affect the performance of their cell devices. When both the molar ratio of Co/Ni and the weight ratio of CoNi/GO are 1:1, the CoNi-RGO counter electrode shows the best performance, indicating the potential of such bimetallic nanoparticle decorated RGO as low-cost and efficient counter electrode to replace noble metal Pt counter electrode for the practical application of DSSCs devices.

电沉积-置换法制备Pt/Ti对电极及其对染料敏化太阳能电池性能的提升

采用电沉积-置换法在Ti片上制备了染料敏化太阳能电池（DSSC）的对电极Pt/Ti. 形貌表征结果显示，与传统热解法制备的Pt/FTO对电极相比，Pt/Ti对电极Ti基底上Pt催化颗粒的粒径和分散性得到显著改善. 光电流-光电压特性曲线测试结果表明，以Pt/Ti为对电极的DSSC与以Pt/FTO为对电极的DSSC相比，光电转化效率提高了20.8%. 由于Pt颗粒分散性和粒径的改善所引起的Pt催化性能的提高、Pt/Ti对电极更低的电阻以及Ti基底更好的反光性能是提升DSSC性能的原因.

Photovoltaic Performance Analysis of Dye-Sensitized Solar Cell Based on the Ag(4,4′-Dicyanamidobiphenyl) Complex as a Light-Scattering Layer Agent and Linker Molecule on TiO2 Photoanode

Light trapping inside the dye-sensitized solar cell (DSSC) is the most effective way to develop the traveling distance by restricting light propagation within the photoanode and promote interaction of incident photons with the sensitizer molecules. This paper covers the role of string shape of Ag(4,4′-dicyanamidobiphenyl) complex (Ag(DCBP)) as a modifier of TiO2 photoanode, to achieve significant progress in the energy conversion efficiency of DSSCs. To study the photovoltaic properties of the standard N719 DSSC, nanocomposite TiO2 suspension with different amount of Ag(DCBP) prepared and deposited on a Fluorine-doped tin oxide (FTO) photoanode as a modified thin film by electrophoretic deposition (EPD). The DSSCs performances studied by monitoring current density–voltage (J–V), open-circuit voltage decay, impedance spectroscopy, and intensity-modulated photocurrent spectroscopy. T he results showed DSSCs made of Ag(DCBP)/TiO2 nanocomposite represented unique optical properties and plasmonic effects because of the presence of Ag(DCBP) complex. In this case, more absorption of dyes occurred because of the high specific surface area of proposed designed photoanode. Under the optimized conditions, the obtained solar cell efficiency was 5.17% which in compare to that obtained from a pure TiO2 cell as 3.06%, i.e., increased by 69.0%, when Ag(DCBP) contained 1.5% of the photoanode composition.

Improvement in Energy Conversion Efficiency by Modification of Photon Distribution within the Photoanode of Dye-Sensitized Solar Cells.

The dye-sensitized solar cell (DSSC) is a potential alternative to the widely used Si-based solar cell, with several advantages including higher energy conversion efficiency under weak and indirect illumination conditions, and the possibility of practical application in urban life due to their exterior characteristics. However, despite these advantages, the energy conversion efficiency of DSSCs has remained low at ∼10%. To improve the efficiency of DSSCs, research has been done on modifying the materials used in DSSC component parts, such as the photoanode, electrolyte, and counter electrode. Another approach is to modify the photoanode to increase the diffusion coefficient, reduce the recombination rate, and enhance the light behavior. One of the most popular methods for improving the efficiency of DSSCs is by trapping and dispersing the incident light using a scattering layer. Use of a scattering layer has shown various and interesting results, depending on the application, but it is currently used only in a simple form and there has been no deep research on the further potential of the scattering layer. In this study, the scattering center was introduced to maximize the effect of scattering. Light distribution near the scattering center, within or on the photoanode, was investigated using finite differential time domain (FDTD) numerical methods. Based on the FDTD analysis, an optimized, dome-shaped three-dimensional modified structure of a transparent photoanode with minimized scattering centers was introduced and indicated the possibility of modifying the photon distribution in the photoanode to enhance the performance of DSSCs. In addition to using the scattering center, we have introduced the structure of the dome-shaped three-dimensional structure to utilize the light distribution within the photoanode. This novel three-dimensional transparent photoanode and scattering center design increased the energy conversion efficiency of DSSCs from 6.3 to 7.2%. These results provide a foundation for investigating the role of the scattering center via further in-depth research. This new three-dimensional photoanode design provides a means to overcome the previous limitations on DSSC performance.

Light Harvesting and Direct Electron Injection by Interfacial Charge-Transfer Transitions between TiO2 and Carboxy-Anchor Dye LEG4 in Dye-Sensitized Solar Cells

Dye-sensitized solar cells (DSSC) have attracted much attention as a promising candidate for next-generation solar cells. Recently, the solar-to-electrical energy conversion efficiency of DSSC was improved up to ca. 14%. Nevertheless, further improvement of the solar energy conversion is required for practical applications of DSSC. The performance of DSSC is limited by energy loss larger than ca. 0.3 eV in the electron injection from photoexcited dyes to TiO2. Interfacial charge-transfer transitions (ICT) between TiO2 and dyes provide a direct electron-injection mechanism with internal quantum efficiency of 100% and without energy loss. Recently, we demonstrated efficient photoelectric conversion due to ICT transitions between TiO2 nanoparticles and 2-anthracenecarboxylic acid. In this paper, we report that ICT transitions between TiO2 nanoparticles and a donor–acceptor organic dye called LEG4 bearing a carboxy anchor group extend the spectral sensitivity of the LEG4-based DSSC to the near IR region. Our ...

Enhanced Efficiency in Dye-Sensitized Solar Cells by Electron Transport and Light Scattering on Freestanding TiO₂ Nanotube Arrays.

Dye-sensitized solar cells (DSSCs) were fabricated with closed- or open-ended freestanding TiO2 nanotube arrays as photoelectrodes that were decorated with carbon materials and large TiO2 nanoparticles (NPs) to enhance energy conversion efficiency. The energy conversion efficiency of DSSCs based on open-ended freestanding TiO2 nanotube arrays increased from 4.47% to 5.39%, compared to the DSSCs based on closed-ended freestanding TiO2 nanotube arrays. In DSSCs based on the open-ended freestanding TiO2 nanotube arrays, the energy conversion efficiency with carbon materials increased from 5.39% to 6.19% due to better electron transport, and that with a scattering layer from 5.39% to 6.24% due to more light harvesting compared to the DSSCs without carbon materials or scattering layer. Moreover, the energy conversion efficiency of DSSCs based on the open-ended freestanding TiO2 nanotube arrays with both carbon materials and scattering layer increased from 5.39% to 6.98%, which is an enhancement of 29.50%. In DSSCs based on the TiO2 nanotube arrays, the carbon materials can improve electron transport by π-π conjugation, and the large TiO2 NPs can enhance the capacity to light-harvest by scattering.

Single-crystalline anatase TiO2 nanoleaf: Simple topochemical synthesis and light-scattering effect for dye-sensitized solar cells

A topochemical process was used to synthesize {010}-faceted leaflike anatase TiO2 nanocrystals from exfoliated layered titanate nanosheets. A light scattering effect of the leaflike anatase nanocrystals with a crystal size of 300nm in length and 30nm in width was studied as a light scattering layer on a P25 nanocrystalline-TiO2 film for dye-sensitized solar cells (DSSCs). The light scattering layer fabricated using the leaflike nanocrystals exhibits a synergistic effect of light scattering and dye-loading for enhancement of light harvesting, which enhanced 28% of energy conversion efficiency of DSSCs by enhancing 33% of Jsc. The leaflike nanocrystals oriented to the direction vertical to the direction of incident light in the scattering layer improve the scattering effect of the scattering layer, and the dye molecules adsorbed on the {010}-faceted anatase exhibit high performance for photoelectron generation.

Surface modification of porous TiO2 electrode through pulse oxidative hydrolysis of TiCl3 as an efficient light harvesting photoanode for dye-sensitized solar cells

A compact thin TiO2 layer suitable for I3−/I− electrolyte could be uniformly deposited along the pore walls in porous TiO2 film by pulse oxidative hydrolysis of TiCl3 solution. When applied the continuous anodic current, the TiO2 layer might be deposited at the entrance to the pores, leading to a decrease in the penetration of electrolyte into the pores of the porous TiO2 film. By tuning the pulse duty cycle and current density, the thin TiO2 layer could provide more active sites for adsorption of dye and improve the electrical contact between TiO2 nanoparticles. Moreover, the compact thin TiO2 layer could deposit on the exposed surface of fluoride-doped tin oxide substrate, giving rise to a suppression of charge recombination. Surface modification of porous TiO2 photoanode through pulse oxidative hydrolysis turned out to have positive effect on the photovoltaic characteristics of dye-sensitized solar cell (DSSC). DSSC with modified photoanode could significantly suppress the dark current density and increase the short-circuit current density in comparison to that with untreated photoanode. The energy conversion efficiency of DSSC was significantly enhanced from 7.12 to 8.47% when using the photoanode post-treated by pulse oxidative hydrolysis of TiCl3.

Composite thin films of titanium dioxide nanoparticles with particle size distribution prepared by electrophoresis

In order to improve the energy conversion efficiency of dye-sensitized solar cells (DSSCs), deposition of anatase titanium dioxide (TiO2) composite thin films as the negative electrode was attempted using constant-current electrophoresis with a colloidal mixture of two types of TiO2 nanoparticles with different sizes and surface properties. The first type was synthesized in the present study and had a size of about 5 nm; these are referred to as TNPs. The second type was commercially obtained TiO2 nanoparticles (P25) with a size of about 20 nm. The P25-to-TNP mass ratio was changed during electrophoresis. Because the TNPs were small and the film had a high specific surface area, the film was deposited to minimize the P25-to-TNP mass ratio in the region close to the entrance window of the DSSC. The upper limit of the film thickness was markedly increased compared to deposition in a colloid consisting of one or two kinds of TiO2 nanoparticles, but without a particle size gradient. A method for calculating the P25-to-TNP mass ratio, the gradient of the number average particle size, and the specific surface area of thin films with a particle size gradient was proposed. The harvesting efficiency for incident light was improved over a wide wavelength range, and as a result, the energy conversion efficiency of DSSCs fabricated using these thin films was increased.

Performance Enhancement of Dye-Sensitized Solar Cells Based on TiO₂ Thick Mesoporous Photoanodes by Morphological Manipulation.

This study is an attempt to give an account of the preparation of mesoporous TiO2 thick templated films of nonsimilar pore architecture and their use in dye-sensitized solar cells (DSSCs). Highly crystallized mesoporous titania thick templated films with four different morphologies including hexagonal, wormlike, cubic, and gridlike mesostructure, have been successfully synthesized through an evaporation-induced self-assembly (EISA) route followed by layer-by-layer deposition. Stabilization, followed by each coating, and calcinations, carried out after every five layers, were used to produce crack-free thick films. These mesoporous templated titanium dioxide samples were characterized by TEM, XRD, SEM, BET, and UV-vis measurements and used as a photoelectrode material in DSSCs. The mesostructured films with a thickness of about 7 μm demonstrated better performance in comparison to nanocrystalline TiO2 films (NC-TiO2) at a film thickness of 13 μm as the most typical films utilized in DSSCs. The findings reveal that a surfactant/Ti ratio change undergone for developing cubic mesostructures can enhance the crystallinity and roughness factor and therefore increase the energy conversion efficiency of DSSC. The cell performances derived from these mesofilms were enhanced compared to the efficiencies reported thus far. The best photovoltaic performance of 8.73% came from DSSC using the cubic mesoporous TiO2 photoelectrode with the following properties: open circuit voltage of 743 mV, short circuit photocurrent density of 16.35 mA/cm(2), and fill factor of 0.72.

Properties of Working Electrodes with Diamond Blends in Dye Sensitized Solar Cells

We prepared blocking layers by adding 0.0 ~ 0.6 wt% nano diamond blends (DBs) to TiO₂ blocking layers to improve the energy conversion efficiencies (ECEs) of dye sensitized solar cells (DSSCs). TEM and micro-Raman spectroscopy were used to characterize the microstructure and phases of DBs, respectively. Optical microscopy and FE-SEM were used to analyze the microstructure of the TiO₂ blocking layer with DBs. UV-VIS-NIR spectroscopy was used to determine the absorbance of the working electrodes. A solar simulator and a potentiostat were used to determine the photovoltaic properties and the impedance of the DSSCs with DBs. From the results of the DBs analysis, we determined a 6.97 ㎚ combination of nano diamonds and graphite. We confirmed that ECE increased from 5.64 to 6.48 % when the added DBs increased from 0.0 to 0.2 wt%. This indicates that the effective surface area and electron mobility increased when DBs were added to the TiO₂ blocking layer. Our results indicate that the ECE of DSSCs can be enhanced by adding an appropriate amount of DBs to the TiO₂ blocking layers.

Effect of ZnO films immersion duration in N719 dye on energy conversion efficiency of DSSCs

In this research, ZnO films composed of porous spherical nanoparticles were prepared by a sol–gel method and used to fabricate dye-sensitized solar cells (DSSCs). ZnO films with different thicknesses and different lengths of immersion duration the films in N719 dye were used for solar energy conversion. Among them, the DSSC of ZnO film 5.6–6.2 µm thick immersed in N719 dye for 30 min has the highest performance efficiency. Inappropriate duration for soaking ZnO films in the dye can cause lower efficiency of the DSSCs caused by dye loading, detachment of ZnO films, reduction in number of free electrons, promotion of the recombination process, and transformation of porous films into denser ones.

Properties of Dye Sensitized Solar Cells with Adding Nano Carbon Black into Blocking Layer

Blocking layers with nano carbon blacks (NCBs) were prepared by adding 0.0 ~ 0.5 wt% NCBs to the TiO₂ blocking layer. Then, dye sensitized solar cells (DSSCs) were fabricated with a 0.45 ㎠ active area. TEM and micro-Raman spectroscopy were used to characterize the microstructure and phases of the NCBs, respectively. Optical microscopy and AFM were used to analyze the microstructure of the TiO₂ blocking layer with NCBs. UV-VIS-NIS spectroscopy was used to determine the band gap of the TiO₂ blocking layer with NCBs. A solar simulator and potentiostat were used to determine the photovoltaic properties and impedance of DSSCs with NCBs. The energy conversion efficiency (ECE) increased from 3.53 to 6.20 % when the NCB content increased from 0.0 to 0.3 wt%. This indicates that the effective surface area and electron mobility increased in the TiO₂ blocking layer with NCBs. However, the ECE decreased when the NCB content was increased to over 0.4 wt%. This change occurred because the effective electron transport area decreased with the addition of excessive NCBs to the TiO₂ blocking layer. The results of this study suggest that the ECE of DSSCs can be enhanced by adding the appropriate amount of NCBs to the TiO₂ blocking layer.