Surface Of TiO2 Film Research Articles

Photochemistry of fac-[Re(CO)3(dcbH2)( trans-stpy)]+: New Insights on the Isomerization Mechanism of Coordinated Stilbene-like Ligands.

In this work, a novel complex fac-[Re(CO)3(dcbH2)( trans-stpy)]+, (dcbH2 = 4,4'-dicarboxylic acid-2,2'-bipyridine; trans-stpy = trans-4-styrylpyridine) was synthesized and characterized toward its spectroscopic, photochemical, and photophysical properties. The experimental data provide new insights on the mechanism of photochemical trans-to- cis isomerization of the stilbene-like ligand coordinated to Re(I) polypyridyl complexes. The new complex exhibits an unusual and strong dependence of the isomerization quantum yield (Φt →c) on the irradiation wavelength. Φt →c was 0.81 ± 0.08 for irradiation at 365 nm and continuously decreased as the irradiation wavelength is shifted to the visible. At 405 nm irradiation Φt →c is almost 2 orders of magnitude lower (0.010 ± 0.005) than that observed at 365 nm excitation. This behavior can be explained by the low-lying triplet metal-to-ligand charge-transfer excited state (3MLCT) that hinders the triplet photoreaction mechanism under visible light absorption. Under UV irradiation, direct population of styrylpyridine-centered excited state (1IL) leads to the occurrence of the photoisomerization via a singlet mechanism. Further experiments were performed with the complex immobilized on the surface of TiO2 and Al2O3 films. The nonoccurrence of isomerization at the oxide surfaces even under UV excitation evidences the role of energy gap between the 1IL/1MLCT states on the photochemical/photophysical processes. The results establish important relationships between the molecular structure and the photoelectrochemical behavior, which can further contribute to the development of solid-state molecular switches based on Re(I) polypyridyl complexes.

The coverage control and electric desorption kinetics of polypyridyl ruthenium dye molecule fixed on the interface of nanoporous TiO2

This paper conducted researches on electric desorption kinetics, desorption mechanism and quantitative desorption of the adsorbed polypyridyl ruthenium based dye on the surface of nanoporous TiO2 film under negative potential. Change external negative potential to obtain the relationship between dye desorption amount of sensitized-TiO2 film and potential. After the negative potential exceeds about −0.5 V, amount of dye left on the surface of TiO2 film decreases rapidly. According to the pseudo-first-order kinetic equation, dye desorption rate kd under potential of −0.6 V is 6.92 × 10−3 s−1. Research the relationship between the amount of desorbed dye and the potential duration, ionic concentration in supporting electrolyte solution as well as film thickness. It implies that the amount of adsorbed dye can be accurately controlled. Based on the measurement and analysis of the adsorption property of desorbed dye through UV–Visible absorption spectroscopy, there is no change of number of absorption peaks of the desorbed dye or no occurrence of new peak, while the absorption peak position of the desorbed dye shows a blue shift. Cyclic voltammetry is used to research the TiO2/dye/electrolyte interface and TiO2/electrolyte interface, and analyze the influence of dye desorption on the cyclic voltammetric response. Two possible dye desorption mechanisms are provided: one is the fracture of ester bond between dye and TiO2 under negative potential; another is the electrostatic repulsion desorption mechanism. Work in this paper is of theoretical guiding significance for compounding new dyes, defining assembly mechanism of dye, enhancing the stability of solar cell, and improving solar cell efficiency.

Characterization of Co:TiO2 Thin Film Grown by MOCVD Technique

The Co:TiO2 thin film was grown on n-type Si(100) by metal organic chemical vapor deposition (MOCVD) technique. The film’s growth parameters are as follow: substrate temperature of 450°C, bubbler temperature of 70°C, reactor chamber pressure of 2 militorr, and growth time of 2 hours. We characterized the structure of film by X-ray Difractometer (XRD), the morphology was characterized by Scanning Electron Microscope (SEM), and the fraction of Co atoms in TiO2 was characterized by Energy Dispersive x-ray Spectroscopy (EDS). The XRD result shows that the Co:TiO2 thin film is an anatase phase crystal dominated by A(213) orientation. Using Warren-Scherrer’s formula, the average grain size of Co:TiO2 is 169 nm. The SEM result shows that the Co:TiO2 film surface is quite coarse with relatively homogeneous grain shape. the average growth rate of Co:TiO2 film is 0.78 μm/h. In addition, the EDS result shows that Co atoms have been incorporated into the film replacing a portion of the Ti atoms by 0.085%.

Kinetics of in situ desorption of dye molecules on sensitized TiO2 nanoparticles in a high concentration solution: ion parasitic adsorption process and mass reference.

The reverse process of dye molecule adsorption on the surface of nanoparticles, that is, the desorption process, has long been neglected in the field of dye-sensitized solar cells (DSCs). It is crucial to develop an in situ technology that controls the rate of dye desorption. Meanwhile, controlling the coverage of dye-sensitized films is still a major challenge. The work presented in this paper applies a simple and effective method to study the in situ mass change responses on dye-sensitized TiO2 films over different potential ranges. The result shows that dye molecule desorption is accompanied by the adsorption of ions in solution. Due to this parasitic adsorption process, the frequency responses in the electrochemical quartz crystal microbalance (EQCM) test cannot be completely attributable to dye molecule desorption. We established a new model to eliminate the impact of this parasitic adsorption process. The kinetics of in situ desorption of dye molecules on sensitized TiO2 nanoparticles in a high-concentration solution was studied. We found that the in situ desorption of dye could be described by pseudo-first-order kinetics. The results suggest that the dye in situ desorption rate is dependent on the bias voltage, and the coverage of dye on the surface of TiO2 films can be further controlled. In-depth research of the dye desorption process is theoretically significant to study DSC stability, new dye synthesis and complex interface structures.

Dye-Sensitized Solar Cells Employing Extracts from Four Cassia Flowers as Natural Sensitizers: Studies on Dye Ingredient Effect on Photovoltaic Performance

Natural dyes extracted from four different flowers, namely, Cassia surattensis, Cassia tora, Cassia alata and Cassia occidentalis were used as sensitizers for TiO2-based dye-sensitized solar cells (DSSC). The dye extracts from flowers were obtained by a simple extraction technique and used without any further purification. Optical characteristics of dye extracts were studied. Fourier-transform infrared (FTIR) spectra were used to identify the constituents of extracted dyes. The photovoltaic performance of DSSC employing dye-capped TiO2 photoanodes was measured. The sensitization performance related to anchoring groups present and interaction between dyes with TiO2 surface is demonstrated. An attempt has been made to rationalize the observations by light absorption of the dye extracts and their adsorption on TiO2. The short-circuit current density (I SC) values ranged from 0.06 mA/cm2 to 0.20 mA/cm2; open circuit voltage (V OC) from 0.292 V to 0.833 V; fill factor (FF) from 0.7 to 0.9; efficiencies (η) from 0.013% to 0.15% and incident photon-to-current conversion efficiency from 13% to 20%, were obtained for DSSC using these natural dye extracts. Cassia occidentalis showed the highest current density of 0.20 mA/cm2 and power conversion efficiency of 0.15%, which was due to better interaction between the carbonyl and hydroxyl group of the anthocyanin molecule of C. occidentalis and surface of TiO2 film. The red and blue shift of absorption wavelength of C. surattensis and the blue shift of absorption wavelength of the C. tora, C. alata and C. occidentalis extract in ethanol solution compared to that on TiO2 film has been used for the interpretation of obtained results.

Performance of E. conferta and G. atroviridis fruit extracts as sensitizers in dye-sensitized solar cells (DSSCs)

Natural dyes extracted from Eleiodoxa conferta and Garcinia atroviridis were used for the first time as photosensitizers in dye-sensitized solar cells (DSSCs). Anthocyanin was identified as the main pigments that sensitize the semiconductor of TiO2 film. Anthocyanin pigment contains hydroxyl and carboxylic groups in the molecule that can attach effectively to the surface of TiO2 film. The optical characteristics of the extracted dye and photovoltaic performance of the cells were studied. The extracts showed UV–vis absorptions in the range of 530–560 nm with broad maxima absorption at ~ 430 nm. FTIR spectra of extraction revealed the presence of anchoring groups. For E. conferta, the photovoltaic performance of the sample with 3.16-μm-thick TiO2 produced the best results with open-circuit voltage (VOC), short-circuit current density (JSC), fill factor (FF), and energy conversion efficiency (ɳ) values of 0.37 V, 6.56 mA/cm2, 0.49, and 1.18%, respectively. The best photovoltaic performance for G. atroviridis was also obtained from the sample with 3.16-μm-thick TiO2 with VOC, JSC, FF, and ɳ values of 0.35 V, 3.74 mA/cm2, 0.65, and 0.85%, respectively.

In situ construction of g-C3N4/TiO2 heterojunction films with enhanced photocatalytic activity over magnetic-driven rotating frame

Corn-shaped TiO2 nanofilms were fabricated by a glycerol-assisted hydrothermal method, and then g-C3N4 was deposited on the surface of TiO2 films using melamine as precursor under air atmosphere by an in site microwave-heating technique. The investigations indicate that microwave-heating process is a facile strategy to obtain g-C3N4 by thermal polymerization of melamine, which can achieve in situ constructing of g-C3N4/TiO2 heterojunction films with high stability. The as-prepared TiO2 films with crack and holes have visible light scattering capability, and the scattering light overlaps with the intrinsic absorption of g-C3N4, leading to an absorption plateau in the range of 400–550nm. Besides, a magnetic-driven rotating frame was developed to enhance the mass transfer processes during the photocatalytic water splitting. The result shows that g-C3N4/TiO2 films exhibit excellent activities under simulated-sunlight irradiation, in addition to the enhanced mass transfer, the overlapped visible light absorption, stable contact and effective charge transfer between g-C3N4 and TiO2 can facilitate the hydrogen production and light utilization efficiency as well. The hydrogen production rate can reach 13.8mmolh−1m−2 over g-C3N4/TiO2 films prepared using 0.5g of melamine and 16.0cm2 of TiO2.

Enhanced photo-catalytic activity of TiO2 films by removal of surface carbon impurities; the role of water vapor

We have studied the photo-catalytic degradation of acetaldehyde over the surface of TiO2 films under UV light (365nm) irradiation both at dry and humid air conditions using a high vacuum chamber equipped with on-line gas-chromatography as a batch-type reactor. Changes of TiO2 surfaces upon the photo-catalysis experiments were studied by X-ray photoelectron spectroscopy. The competitive adsorption of water and acetaldehyde resulted in the reduction of reaction rate of photo-catalytic degradation of acetaldehyde under the UV light irradiation. The photo-catalytic reaction rate of TiO2 films towards acetaldehyde mineralization increased when the photo-catalysis experiments were performed repeatedly and it was much more pronounced under humid conditions. Our XPS analysis revealed that carbon impurities on the surface of TiO2 films were removed by UV-light driven photo-catalytic mineralization under humid conditions. Water vapor facilitated the photo-catalytic removal of carbon impurities from TiO2 surface generating additional active sites of TiO2 which resulted in the enhanced photo-catalytic activity of TiO2 films.

Enhance photovoltaic performance of tris(2,2′-bipyridine) cobalt(II)/(III) based dye-sensitized solar cells via modifying TiO2 surface with metal-organic frameworks

A very thin blocking layer of a metal organic framework ZIF-8 has been successfully coated on the surface of mesoporous TiO2 films. Compared to the uncoated samples, dye-sensitized solar cells with such films exhibit enhanced open circuit voltage (VOC) and short circuit current (JSC) by 3% and 21%, respectively, leading to a 9.42% energy conversion efficiency using tris(2,2′-bipyridine) cobalt(II)/(III) redox mediator. The electron lifetimes as well as dye loading on TiO2 working electrodes were found to increase after ZIF-8 treatment, which is responsible for the improvement of JSC. An increase of charge recombination resistance between working electrode and organic electrolyte, as is characterized by electrochemical impedance spectra, is proposed to be the reason for the increased VOC, as there is no TiO2 conduction band shift after the treatment of ZIF-8.

Influence of humidity on the photo-catalytic degradation of acetaldehyde over TiO2 surface under UV light irradiation

We have studied the influence of water vapors on the activity of the photo-catalytic oxidation of acetaldehyde on the surface of TiO2 film under UV light (365nm) irradiation. Photo-catalysis experiments were performed at atmospheric conditions under various humidity levels (0, 16.8, and 33.6 relative humidity%) using a high vacuum chamber equipped with online gas-chromatography as a batch-type reactor. Acetaldehyde and H2O molecules competitively adsorbed on the surface of TiO2 film and the increase in the humidity decreased both the acetaldehyde removal and CO2 evolution rates. The rate of CO2 evolution was even more influenced by the humidity level of the gas mixture compared to the acetaldehyde removal rate, particularly over the certain level of relative humidity. We evidenced that the total oxidation of acetaldehyde was majorly mediated by oxygen molecules rather than H2O vapor under our experimental conditions. It is suggested that photo-catalytic total oxidation of acetaldehyde was promoted by the presence of large active sites ensemble near the adsorbed acetaldehyde, which were available to oxygen. Increase of humidity level disturbed this large ensemble, resulting in the reduction of photo-catalytic degradation rate of acetaldehyde under UV light irradiation.

Buried Charge at the TiO2/SrTiO3 (111) Interface and Its Effect on Photochemical Reactivity

High-temperature annealing in air is used to produce SrTiO3 (111) surfaces with two types of atomically flat terraces: those that promote photoanodic reactions and those that promote photocathodic reactions. Surface potential measurements show that the photocathodic terraces have a relatively more positive surface potential than the photoanodic terraces. After depositing thin TiO2 films on the surface, from 1 to 13 nm thick, the surface of the film above the photocathodic terraces also has photocathodic properties, similar to those of the bare surface. While a more positive surface potential can be detected on the surface of the thinnest TiO2 films (1 nm thick), it is undetectable for thicker films. The persistence of the localized photocathodic properties on the film surface, even in the absence of a measurable difference in local potential, indicates that the charge associated with specific terraces on the bare SrTiO3 (111) surface remains localized at the TiO2/SrTiO3 interface and that the buried charge influences the motion of photogenerated carriers.

Application of highly reflective spacer layer in monolithic dye-sensitized solar cells

Monolithic dye-sensitized solar cells (DSSCs) based on TiO2/spacer/carbon triple mesoporous films are low-cost, ease of fabrication with screen printing technology, possessing great potential to produce electricity from sunlight. The power conversion efficiency is still low compared to commercial photovoltaic technology. For DSSCs with platinum coated FTO or gold as counter electrode, the mirror like surface of counter electrode can reflect visible light back to be re-absorbed by dye-sensitized TiO2 film. However, for monolithic DSSCs, there is no reflection layer. To enhance absorbance of incident photons is an important way to improve photocurrent of monolithic DSSCs. Spacer film can be used as scattering layer to reflect visible light. However, spacer usually absorbs large amount of dyes due to large surface area and surface basic sites. Here, we report highly reflective spacer with no dyes anchoring onto surfaces of spacer. The scattering centers are sub-micrometer voids created by decomposing sub-micrometer polystyrene (PS) spheres. The building blocks are composed of rutile TiO2@SiO2. Rutile TiO2 was selected due to its large refractive index. SiO2 was coated on surface of rutile TiO2 to avoid dye adsorption. Moreover, the sub-micrometer voids provide fast transporting channels for redox species. To fabricate spacer paste that can be used with screen printing method to produce film, rutile TiO2@SiO2 nanoparticles and PS spheres with diameter of 400nm were first synthesized separately and then, they were mixed homogeneously by ball milling with addition of ethyl cellulose binder and organic dispersant medium (α-terpineol). Rutile TiO2 was obtained by reaction of TiCl4 in HCl aqueous solution at 80°C and sub-micrometer PS spheres were synthesized with emulsion polymerization of styrene monomer at 70°C. Rutile TiO2@SiO2 core@shell nanoparticles were obtained by hydrolysis of tetraethyl silicate on the surface of rutile TiO2. The UV-visible reflection spectra of sintered spacer film at 500°C showed that the spacer film with ratio (rutile TiO2@SiO2 to polystyrene) of 1:0.2 or 1:0.4 have maximum reflectivity in the visible range. However, the conventional ZrO2 spacer film with the same thickness has much weaker reflectivity. The dye absorption test of bilayer film with spacer lying top of TiO2 film reveals that the dye molecules can easily go through spacer film to absorb onto surface of mesoporous TiO2 film while the spacer film on the top keeps white color unchanged. Scanning electron images of spacer film also showed that sub-micrometer voids distributed uniformly in the film and the diameter of voids is similar to that of PS spheres. These sub-micrometer voids in spacer film can provide fast transporting channels for redox species, facilitating dye regeneration. By replacing the conventional ZrO2 spacer with the advanced spacer, photocurrent density of monolithic DSSCs was increased by 25%. As a result, the power conversion efficiency has been improved to 4.61% from 3.95% with non-volatile iodine-free polymer gel electrolyte. These results endow spacer a new ability in the device and provide another guideline to enhance photocurrent of monolithic dye-sensitized solar cells. The design of spacer in this work may find other applications in the area of optics, catalyst, etc.

Harnessing Photovoltage: Effects of Film Thickness, TiO2 Nanoparticle Size, MgO and Surface Capping with DSCs.

High photovoltage dye-sensitized solar cells (DSCs) offer an exceptional opportunity to power electrocatalysts for the production of hydrogen from water and the reduction of CO2 to usable fuels with a relatively cost-effective, low-toxicity solar cell. Competitive recombination pathways such as electron transfer from TiO2 films to the redox shuttle or oxidized dye must be minimized to achieve the maximum possible photovoltage (Voc) from DSC devices. A high Voc of 882 mV was achieved with the iodide/triiodide redox shuttle and a ruthenium NCS-ligated dye, HD-2-mono, by utilizing a combined approach of (1) modulating the TiO2 surface area through film thickness and nanoparticle size selection, (2) addition of a MgO insulating layer, and (3) capping available TiO2 film surface sites post film sensitization with an F-SAM (fluorinated self-assembled monolayer) treatment. The exceptional Voc of 882 mV observed is the highest achieved for the popular NCS containing ruthenium sensitizers with >5% PCE and compares favorably to the 769 mV value observed under common device preparation conditions.

Photoelectrocatalytic reduction of CO2 to methanol over the multi-functionalized TiO2 photocathodes

The photoelectrocatalytic (PEC) reduction of CO2 to chemical fuels was achieved by utilizing the multi-functionalized TiO2 film photocathodes. On the surfaces of TiO2 films, Pd nanoparticles were introduced to catch protons, molecules of Eosin Y disodium salt were embedded to absorb solar energy, and four different amine ligands were immobilized to capture and activate CO2. In the novel PEC cells, multi-functionalized TiO2 and Co-Pi/W:BiVO4 films were served as photocathode and the counter electrode, respectively. It was found that methanol was the major liquid product. Besides, some ethanol and acetone can be detected as well. The maximum formation rate and the highest selectivity of methanol were 43.6μMcm−2h−1 and approximately 100%, respectively. The Faradaic efficiencies of the PEC cells can exceed 1000% with the aid of photoelectrons. The 13CO2 labeling experiments verify that methanol and carbon monoxide are derived from CO2.

Effect of surface morphology on wettability conversion

A hierarchical structural surface of TiO2 film with reversibly light-switchable wettability between superhydrophobicity and superhydrophilicity on metal substrate was fabricated through simply dip-coating method from TiO2 precursor solution containing TiO2 nanoparticles with the average diameter 25 nm (P25), followed by heat-treatment and modification with fluoroalkylsilane (FAS) molecules. The morphology, phase and crystallographic structure, and chemical composite of the as-prepared TiO2 film were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The wettability of TiO2 film was characterized by a drop shape analyzer. The water contact angle of superhydrophobic TiO2 film was up to 165.6°. Under UV irradiation, the water contact angle decreased and the superhydrophobic TiO2 film became superhydrophilic because of hydroxyl groups absorption on the TiO2 surface. Meanwhile, the surface morphology of TiO2 film, which resulted from the TiO2 nanoparticles added in TiO2 precursor solution, had a significant effect on the wettability conversion of TiO2 film and enhanced the switch from hydrophobicity to hydrophilicity. The wettability could be reversibly switched between superhydrophobicity and superhydrophilicity via alternation of UV exposure and dark storage.

Study on the chemical bond structure and chemical stability of N doped into TiO 2 film by N ion beam implantation

Titanium dioxide (TiO2) film was deposited by DC pulse magnetron sputtering technique. The surface of TiO2 film was implanted by N ion beam at room temperature and N doped TiO2 (N-TiO2) film was obtained. X-ray diffractometer result showed that with the increase of sputtering power, the crystal structure of TiO2 film changed from amorphous to anatase polycrystalline structure. Transmission electron microscopy result revealed that nanoscale clusters existed in amorphous TiO2 film. The bandgap of TiO2 film was about 3.28 ± 0.05 eV. X-ray photoelectron spectroscopy results revealed that N ion was doped into TiO2 film as Ti–N and Ti–NO bonds. With increasing TiO2 film crystallinity, N atom-percent and ratio of Ti–N to Ti–NO decreased and increased, respectively. TiO2 film deposited with 900 W in sputtering power, N atom-percent decreased to 6.6 at.% and ratio of Ti–N to Ti–NO increased to 0.81:1. The bandgap of N-TiO2 film was about 3.02 ± 0.07 eV. N atom-percent and ratio of Ti–N to Ti–NO kept at 2.73 ± 0.26 at.% and (0.87 ± 0.03):1 for all annealed N-TiO2 films. The bandgap of annealed N-TiO2 film was about 3.16 ± 0.03 eV. So, the crystallinity of TiO2 film was one of most important parameters, which influenced the chemical bond structure and chemical stability of N in TiO2 films.

Visible-Light-Driven Water Oxidation on a Photoanode by Supramolecular Assembly of Photosensitizer and Catalyst.

A ruthenium water oxidation catalyst (WOC) bearing hydrophobic ligands was incorporated on the surface of a dye-sensitized nanostructured TiO2 film by formation of a host-guest adduct with the dye. This provides a new strategy for constructing photocatalytically active electrodes for water oxidation. The resultant photoanode exhibits a photocurrent of 800 μA cm-2 under visible-light illumination (λ>400 nm, 300 mW cm-2 ) and 240 μA cm-2 under simulated sunlight illumination (AM 1.5G, 100 mW cm-2 ) with an applied bias of 0.2 V vs. NHE in neutral phosphate buffer.

Influence of an Al-blended TiO2 photoanode on the photovoltaic properties of n-DSSCs

ABSTRACTThe performance of n-type dye-sensitized solar cells (n-DSSCs) based on a Co complex redox electrolyte were investigated with a photoanode composed with mixer consists of both TiO2 and AlCl3. The surface of TiO2 films coated on FTO glass substrates was amended by soaking them in a TiCl4:AlCl3 blended aqueous solution at different molar ratios, and calcining them to yield the surface-modified photoelectrodes (Ti:Al/TiO2). An enhancement in the power conversion efficiency 2.02% of the resulting n-DSSCs with Ti:Al (9:1)/TiO2 compared to the reference cell by the plain TiO2. The dark current measurements, incident photon-to-current conversion, and efficiency electrochemical impedance spectroscopy (EIS) revealed that the combination of a mixer onto the TiO2 film led to the delay of the charge recombination among the photo-injected electrons and Co complex redox electrolyte, resulting in an enhanced short-circuit current and open-circuit current, compared to device without surface modification.

The investigation of band gap and N chemical bond structure of N–TiO2 film prepared by N ion beam implantation

Titanium dioxide (TiO2) film was deposited by the direct current pulse magnetron sputtering technique. Then the surface of TiO2 film was implanted by the N ion beam at room temperature. Through this way, N-doped TiO2 (N–TiO2) film was obtained and the band gap of N–TiO2 film was decreased to 2.97 eV. XPS result revealed that N ion was doped into TiO2 film as Ti–N and Ti–NO bonds. N ion was substitutionally/interstitially doped into TiO2 crystal lattice and Ti–N bond was formed. N ion was doped into amorphous TiO2 and Ti–ON bond was formed. The polycrystal TiO2 film could result in that more N ion was substitutionally/interstitially doped into TiO2 crystal lattice, which could effectively narrow the band gap of N–TiO2 film. This work provides a potential N doping method which could be applied commercially.

Fabrication of three-dimensional CuInS2 solar-cell structure via supercritical fluid processing

In this study, we fabricated a three-dimensional CuInS2 solar-cell structure using supercritical fluid deposition and sulfurization, in which p-n junction is formed at the large surface of a nanoporous n-type TiO2 film filled with a p-type CuInS2 semiconductor to facilitate the efficient collection of photoinduced electrons and holes. Using the reductive reaction of organometallic precursors dissolved in supercritical fluid at the surface, we successfully and efficiently deposited Cu–In film inside the nanoporous film consisting of TiO2 nanoparticles with a diameter of a few tens of nanometers. The CuInS2 film formed following the sulfurization of the Cu–In film exhibited an ideal band gap (1.5eV) and photoconductivity. The results obtained in this study expand the applicability of supercritical fluid technology to the fabrication of chalcogenide semiconductors inside nanostructured materials and will contribute to the future development of or improvement in various types of energy devices.