Incident Photon Current Efficiency Research Articles

Gamma-irradiated stibnite thin films set a remarkable benchmark performance for photoelectrochemical water splitting.

The study sets out to show the positive impact of sulfur vacancy engineering on the structural, morphological, optical, electrical, and photoelectrochemical (PEC) properties of Sb2S3 films synthesized using the spin coating technique. The produced films were exposed to γ-irradiation with different doses from 0 to 20 kGy. We have demonstrated the formation of sulfur vacancies and loss of oxygen content in the irradiated samples. XRD measurements revealed that all films exhibit a polycrystalline structure, and the crystallite size increases with the rising radiation dose, reaching the highest value of 87.4 nm measured for the Sb2S3 film irradiated with 15 kGy. The surface roughness of the irradiated samples increases with increasing γ-irradiation dose. The increase in surface roughness not only raises the active sites but enhances the conductivity of the Sb2S3 material as well. The wettability properties of the irradiated films were affected by γ-irradiation doses and the sample irradiated with 15 kGy exhibited the lowest hydrophobicity compared to others. The Hall measurements reveal that irradiated samples exhibit p-type semiconductor behavior. The optical band gap decreased progressively from 1.78 eV to 1.60 eV up to the irradiation dose of 15 kGy and slightly increased thereafter. The irradiated sample with 15 kGy showed a maximum photocurrent density of ca. 1.62 mA cm-2 at 0 V vs. reverse hydrogen electrode (RHE) under AM 1.5 G illumination with applied bias photon-to-current efficiency (ABPE) of 0.82% at 0.47 V vs. RHE, suggesting superior PEC water splitting performance compared to other samples. At 0 V vs. RHE and 648 nm, the incident photon current efficiency (IPCE) and absorbed photon current efficiency (APCE) of the photocathode irradiated with 15 kGy are significantly higher than those of the other photocathodes with values of 9.35% and 14.47%, respectively. Finally, Mott-Schottky measurement was also performed on all photocathodes to estimate their acceptor density and flat band potential.

Photovoltaic Measurement Under Different Illumination of the Dye-Sensitized Solar Cell With the Photoanode Modified by Fe2O3/g-C3N4/TiO2 Heterogeneous Nanofibers Prepared by Electrospinning With Dual Jets

In this study, iron oxide (Fe2O3)/graphitic carbon nitride (g-C3N4)/titanium dioxide (TiO2) nanofibers (NFs) were used as an additional layer on photoanode in dye-sensitized solar cells (DSSCs) to improve the photovoltaic performance of DSSCs. The nanofibers were prepared by electrospinning with double jets. The heterogeneous nanofiber composite mainly includes Fe2O3, g-C3N4, and TiO2. The Fe2O3/g-C3N4/TiO2 NFs were characterized by X-ray diffractometer (XRD), and the surface morphology was observed by a field emission scanning electron microscope (Fe-SEM). The electrochemical impedance spectroscopy (EIS) was applied to analyze the impedance of the cell. The incident photon current efficiency (IPCE) measurements were applied to determine the quantum efficiency, and ultraviolet-visible (UV-Vis) spectrophotometer was applied to observe the dye adsorption and absorption wavelength. To understand the performance of the modified photoanodes in DSSCs, we analyzed the photovoltaic parameters. The results suggest that the addition of Fe2O3/g-C3N4/TiO2 NFs is able to improve the conversion efficiency of the modified DSSCs to 4.81%. In addition, the efficiency under different illumination was also analyzed, and the highest conversion efficiency was 6.81% at 30 mW/cm2.

Efficient and Stable MoOX@Mo-BiVO4 Photoanodes for Photoelectrochemical Water Oxidation: Optimization and Understanding

In this study, we propose a facilely dip-coated and intermediate heat-treated MoOX@Mo-BiVO4 photoanode that displays extremely efficient and stable photoelectrochemical H2 production. The formation of MoOX as an intermediate species is investigated using time of flight-secondary ion mass spectrometry (TOF-SIMS). The MoOX@2% Mo-BiVO4 photoanode exhibited a photocurrent density of approximately 1 mA cm–2 at 1.23 V versus the reversible hydrogen electrode (RHE), which was 5.5 times higher when compared with that of the BiVO4 photoelectrode because of the formation of MoOX and the induced oxygen vacancies (VOs), which are beneficial for the suppression of electron–hole recombination. The incident photon current efficiency of approximately 17.7% for the MoOX@2% Mo-BiVO4 photoanode is a noticeable improvement over the pure BiVO4 photoelectrode. The H2 and O2 productions of the MoOX@2% Mo-BiVO4 photoanode after 2 h were 32.46 and 15.85 μmol cm–2, respectively, which reached approximately 85% Faradaic efficiency, at 1.23 V versus RHE under 100 mW/cm2.

N, P Self-Doped Porous Carbon Material Derived from Lotus Pollen for Highly Efficient Ethanol-Water Mixtures Photocatalytic Hydrogen Production.

Porous biochar materials prepared with biomass as a precursor have received widespread attention. In this work, lotus pollen (LP) was used as the carbon source, a variety of the pollen carbon photocatalyst were prepared by a two-step roasting method. A series of characterizations were carried out on the prepared samples, and it was found that the average particle size was about 40 μm. They also exhibit a typical amorphous carbon structure and a porous structure with a network-like interconnected surface. The photocatalytic hydrogen production performances of lotus pollen carbon (LP-C) and commercial carbon black (CB) were measured under the full spectrum illumination. LP-C-600 showed the best hydrogen production performance (3.5 μmol·g−1·h−1). In addition, the photoelectrochemical (PEC) measurement results confirmed that the LP-C materials show better incident photon-current efficiency (IPCE) performance than the CB materials in the neutral electrolyte. This is because the unique surface wrinkling, hierarchical porous structure, and the N, P self-doping behavior of the LP-C samples are able to improve the light utilization efficiency and the carrier separation/transfer efficiency, thereby further improving the overall hydrogen production efficiency.

Highly efficient and stable WO3/MoS2-MoOX photoanode for photoelectrochemical hydrogen production; a collaborative approach of facet engineering and P-N junction

In this paper, we demonstrate a facet-controlled WO3 nanoplate heterojunction with MoS2-MoOX nanosheets that produces extremely efficient and stable photoelectrochemical H2 production. Furthermore, the effect of the hydrothermal process time (t = 1, 2, and 3 h) for the WO3 photoanode and drop-casting process of the MoS2 nanosheets (4, 8, and 12 times) to obtain the optimum amount of the material (MoS2 and MoOX) for the PEC performance of the WO3/#n-MoS2 and WO3/#n-MoS2-MoOX (n = 4, 8, and 12) photoanodes were investigated. The photocurrent density of the WO3/MoS2-MoOX photoanode was approximately 2.15 mA.cm−2 at 1.23 V vs. RHE, which was 8.6 and 1.2 times higher compare to pure WO3 and WO3/MoS2 photoelectrodes, respectively. The incident photon current efficiency of the WO3/MoS2-MoOX photoanode is approximately 27.5%, which is a significant improvement over that of bare WO3. The WO3/MoS2-MoOX photoanode produced 54.5 μmolcm−2 of H2 and 25.8 μmolcm−2 of O2 after 2 h, at 1.23 V vs. RHE and 100 mWcm−2. The electrochemical kinetics clearly showed that water oxidation reaction was accelerated. The WO3/MoS2-MoOX photoanode, which was developed through simple and facial drop casting of MoS2 nanosheets onto WO3 photoanode, resulted in effective photogenerated carrier separation and enhanced oxygen evolution reactions on the anode surface.

Materials characterization of TiO2 nanotubes decorated by Au nanoparticles for photoelectrochemical applications.

The structural and chemical modification of TiO2 nanotubes (NTs) by the deposition of a well-controlled Au deposit was investigated using a combination of X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Scanning Transmission Electron Microscopy (STEM), Raman measurements, UV-Vis spectroscopy and photoelectrochemical investigations. The fabrication of the materials focused on two important factors: the deposition of Au nanoparticles (NPs) in UHV (ultra high vacuum) conditions (1–2 × 10−8 mbar) on TiO2 nanotubes (NTs) having a diameter of ∼110 nm, and modifying the electronic interaction between the TiO2 NTs and Au nanoparticles (NPs) with an average diameter of about 5 nm through the synergistic effects of SMSI (Strong Metal Support Interaction) and LSPR (Local Surface Plasmon Resonance). Due to the formation of unique places in the form of “hot spots”, the proposed nanostructures proved to be photoactive in the UV-Vis range, where a characteristic gold plasmonic peak was observed at a wavelength of 580 nm. The photocurrent density of Au deposited TiO2 NTs annealed at 650 °C was found to be much greater (14.7 μA cm−2) than the corresponding value (∼0.2 μA cm−2) for nanotubes in the as-received state. The IPCE (incident photon current efficiency) spectral evidence also indicates an enhancement of the photoconversion of TiO2 NTs due to Au NP deposition without any significant change in the band gap energy of the titanium dioxide (Eg ∼3.0 eV). This suggests that a plasmon-induced resonant energy transfer (PRET) was the dominant effect responsible for the photoactivity of the obtained materials.

Ultrasonically prepared photocatalyst of W/WO3 nanoplates with WS2 nanosheets as 2D material for improving photoelectrochemical water splitting

A sonochemical treatment has been an emerged technique as an interesting method for fabricating different photocatalysts with unique photoelectrochemical (PEC) properties. This study investigated the PEC performance of WO3 with WS2 nanosheets as a 2D material before calcination (WO3/WS2-90) and after calcination (WO3/WS2-450) prepared with sonochemical treatment. The WS2 nanosheets were prepared from a liquid exfoliation phase with few-layer nanosheets, approximately 6.5 nm in thickness. The nanosheets were confirmed by UV–Vis spectroscopy and atomic force microscopy. Further, XPS, RAMAN, and SEM-EDAX analyses indicated that, following calcination of the WO3/WS2 electrode, the WS2 nanosheets initially transformed to 2D-WO3. After depositing the WS2 nanosheets on the WO3, the photocurrent density increased substantially. The WO3/WS2-450 films after calcination showed a photocurrent density of 5.6 mA.cm−2 at 1.23 V vs. Ag/AgCl, which was 3.1 and 7.2 times higher, respectively than those of the WO3/WS2-90 before calcination and pure WO3. Mott-Schottky and electrochemical impedance spectroscopy analyses confirmed the fabrication of the WO3/WS2 photoanode after calcination. The deposition of WS2 nanosheets onto pure WO3 increased the donor concentration (24-fold), reduced the space charge layer (4.6-fold), and decreased the flat band potential (1.6-fold), which could all help improve the photoelectrochemical efficiency. Moreover, the incorporation of WO3 with WS2 nanosheets as a 2D material (WO3/WS2-450) enhanced the incident photon current efficiency (IPCE) by 55%. In addition, the applied-bias photon-to-current conversion efficiency of the WO3/WS2-450 films was approximately 2.26% at 0.75 V (vs. Ag/AgCl), which is 5.6 and 9 times higher, respectively than those of WO3/WS2-90 and pure WO3.

Sensitization of SnO2 Single Crystals with Multidentate‐Ligand‐Capped PbS Colloid Quantum Dots to Enhance the Photocurrent Stability

AbstractA PbS quantum dot (QD) sensitized SnO2 solar cell has the advantage of producing photocurrent from near‐infrared to the ultraviolet that covers much of the higher energy solar spectrum. However, the long‐chain ligands, that are frequently used to cap as‐synthesized QDs, inhibit the charge transfer ability to the sensitized substrate, decreasing the photovoltaic efficiency in the device. Herein, we present a fast and efficient ligand‐exchange strategy for the replacement of synthetically convenient hydrophobic oleic acid (OA) ligands with short‐chain multidentate hydrophilic ligands such as meso‐2,3‐dimercaptosuccinic acid (DMSA) that increase the electronic coupling to the SnO2 substrate. Results from ultraviolet‐visible‐near‐infrared (UV‐Vis‐NIR) spectroscopy, X‐ray diffraction (XRD) measurements, and high‐resolution transmission electron microscopy (HR‐TEM) micrographs verify that this ligand‐exchange method produces no significant QD size or crystal‐structure changes. X‐ray photon spectra (XPS) results suggest that thiol groups from DMSA are likely bound to the PbS QDs compared to other bifunctional ligands. The PbS QDs sensitized SnO2 single crystals were characterized with atomic force microscopy (AFM), and with incident photon current efficiency (IPCE) spectra. Furthermore, it was shown that the IPCE of DMSA‐capped PbS QDs sensitized SnO2 single crystals retains >80% of its initial value after >7 hours of illumination within an electrolyte containing a high concentration of NaI whereas other ligand capped PbS QDs degraded much more rapidly.

Selective synthesis of methanol by photoelectrocatalytic reduction of CO2 over PANI-CuFe2O4 hybrid catalyst

In this work, a hybrid photocatalyst, PANI-CuFe2O4 was synthesized, characterized and used as a photocathode for the photoelectrocatalytic (PEC) reduction of CO2 to methanol selectively under 470 nm wavelength light irradiation at applied potential -0.4 V vs NHE. The PEC results showed that the combination of PANI with CuFe2O4 could increase the rate of PEC CO2 reduction to methanol owing to the increase of CO2 chemisorption at the photocathode surface and at the same time by facilitating the separation of photogenerated electron-hole (e−/h+) pairs during CO2 reduction. The rate of methanol formation was found maximum as 49.2 μmole g−1.h−1 with 73% Faradaic efficiency. The incident photon current efficiency (IPCE) and quantum efficiency (QE) for PEC CO2 reduction was achieved as 7.11% and 23.9% respectively. The PEC results demonstrated that the bias potential played a significant role in the separation of e−/h+ pairs and enhanced the PEC CO2 reduction activity of the hybrid photocatalyst.

Photoelectrochemical activity of CuO-CdS heterostructured catalyst for CO2 reduction

The present study explored the efficiency of a p-n heterostructured hybrid catalyst CuO-CdS to convert CO2 selectively into methanol by photoelectrochemical (PEC) method under concurrent visible light irradiation and a bias potential -0.4 V vs. NHE. The results showed that the inclusion of CdS with CuO significantly enhanced the activity of PEC CO2 reduction to produce methanol by facilitating the separation of photogenerated electron-hole (e−/h+) pairs through the p-n heterostructured architectures. The yield of methanol, the incident photon current efficiency (IPCE) and quantum efficiency (QE) in PEC CO2 reduction were achieved 35.65 μmoleL−1cm−2, 20.24% and 24.11%, respectively. The present work bears a new understanding into the fabrication of high-performable artificial p-n type heterostructured catalyst which is capable to function as a catalyst for photocathode for the reduction of CO2 and remarkable improvement in methanol yield under visible light illumination.

Photocharged molybdenum-doped BiVO4 photoanodes for simultaneous enhancements in charge transport and surface passivation

The two main drawbacks of monoclinic bismuth vanadate (BiVO4: BVO) as a photoanode, i.e., poor charge transport property and fast electron-hole recombination, were improved by simultaneous Mo doping and photocharged surface passivation methods. First, molybdenum-doped BiVO4 (BiVO4: Mo) was prepared to control the donor concentration without producing any secondary phase. Subsequently, photocharging treatment of the Mo-BVO photoanode induced a cathodic shift in onset potential, ~0.15 V (0.75–0.6 V vs RHE) and improved the photocurrent density (~2.2-fold). Moreover, the photocharged 2% Mo-BVO photoanode exhibited an enhanced incident photon current efficiency (IPCE) of about 50% compared to only around 30% (440 nm > λ > 330 nm range) for the non-photocharged photoanode. Mott-Schottky analysis revealed that 2% Mo doping greatly increased the donor concentration (~1000-fold), whereas the photocharging technique only slightly increased the donor concentration (~1.5-fold).

Enhancing the power conversion efficiency of SrTiO3/CdS/Bi2S3quantum dot based solar cell using phosphor

The role of down-conversion phosphorescence in the enhancement of power conversion efficiency (PCE) of TiO2: SrTiO3/CdS/Bi2S3/ZnS: Cu heterostructure solar cell is reported here. ZnS:Cu is used as phosphor which converts a fraction of the ultra violet energy to visible range, increasing the light harvesting capacity. Also this acts as a passivation layer, to reduce the charge recombination. SrTiO3 nanoparticles with spherical morphology were synthesized by co-precipitation technique and CdS, Bi2S3 and ZnS:Cu were grown on the SrTiO3 by successive ionic layer adsorption and reaction (SILAR) method after optimizing the Cu concentration. The structural, morphological and composition were studied by XRD, SEM, TEM and XPS measurements. J-V measurements of TiO2:SrTiO3/CdS/Bi2S3/ZnS:Cu3 structure based solar cell are done by solar simulator under 1.5 AM and found to exhibit an enhancement in PCE to the tune of 55% than SrTiO3/CdS/Bi2S3 (pristine) based solar cell. Incident Photon Current Efficiency (IPCE) spectrum covered a spectral range of 400 to 900 nm for TiO2:SrTiO3/CdS/Bi2S3/ZnS:Cu3 cell with the maximum IPCE ~51%. Electrochemical impedance analysis is also carried out in the form of Nyquist and Bode phase plots for the fabricated solar cells which possess low values of Rs, Rct and longer life time for the charge carriers which is favorable for higher PCE.

Photoelectrocatalytic Reduction of Carbon Dioxide to Methanol Using CuFe2O4 Modified with Graphene Oxide under Visible Light Irradiation

Photoelectrocatalytic reduction of CO2 into valuable products can provide energy in a sustainable way with leveling off of the concentration of CO2 in our environment. In this study, graphene oxide (GO) incorporated with copper ferrite (CuFe2O4) has been employed to enhance photoelectrocatalytic CO2 reduction under visible light. The TEM and XPS characterization indicated a strong interaction between the CuFe2O4 and GO in the hybrid catalyst. The GO incorporation reduced the e–/h+ recombination in the hybrid catalyst by trapping the photoexcited electrons from CuFe2O4 leading to high methanol yield of 28.8 μmol L–1 cm–2 at 20.5% quantum efficiency. The incident photon current efficiency (IPCE) and Faradaic efficiency for methanol formation were observed as 8.02% and 87%, respectively. The results showed that the photoelectrocatalytic activity for CO2 reduction can be improved by incorporating GO with CuFe2O4, and it provides a universal platform to fabricate GO–CuFe2O4 based hybrid photocatalyst with prom...

The photoelectrochemical properties of Sn2Nb2O7 photoanode

Sn2Nb2O7 photoanode has been fabricated by the electrophoretic deposition method and its photoelectrochemical (PEC) properties were studied carefully. The energy band structure of Sn2Nb2O7 was analyzed by Mott-Schottky plots, the results show that its energy band structure matches the requirement of PEC water splitting, the low absolute onset potential of −0.12 V vs NHE achieved with the Sn2Nb2O7/Co-Pi. The influence of film thickness and calcination temperature on the photocurrent of Sn2Nb2O7 was studied, and an optimum condition was identified. The obtained maximum photocurrent density was 0.18 mA/cm2. After surface modification with the water-oxidation electrocatalyst Co-Pi, the photocurrent density was improved furtherly, reached to 0.24 mA/cm2, and the incident photon current efficiency (IPCE) value increased to 2.25% when irradiated by 365 nm light. Water oxidation was carried out over Sn2Nb2O7 photoanode, the evolved oxygen reached to 3.5 μmol within 100 min at the experimental conditions. Electrochemical impedance spectroscopy has been performed to investigate the kinetics of electrolyte and electrode interface.

An organic thin film photodiode as a portable photodetector for the detection of alkylphenol polyethoxylates by a flow fluorescence-immunoassay on magnetic microbeads in a microchannel

An organic thin film photodiode (OPD) was successfully employed as a portable photodetector in a competitive enzyme-linked immunosorbent assay (ELISA) of a class of nonionic surfactants, namely alkylphenol polyethoxylates (APnEOs) which are an environmental pollutant. Microbeads that were chemically immobilized with an anti-APnEOs antibody were used in the assay. The OPD consisted of a layer of copper phthalocyanine (CuPc), C60 and a second layer of bathocuproine (BCP) with a bulk heterojunction composed of CuPc and C60 prepared by a vapor deposition method on an indium-tin oxide coated glass substrate. The OPD showed an incident photon-current efficiency (IPCE) of approximately 19% for light at a wavelength of 585 nm. This relatively high IPCE at 585 nm makes it suitable for detecting the fluorescence of resorufin (λem=585 nm), the product of the competitive ELISA, produced through the enzymatic reaction of Amplex Red with horseradish peroxidase (HRP) and H2O2. A fluorometric detector was assembled on a microchip by combining the fabricated OPD and a commercial LED as a photodetector and a light source, respectively. The photocurrent of the OPD due to the fluorescence of resorufin was proportional to the concentration of resorufin in the concentration range from 0 to 8 μM. When the fabricated OPD was used as a portable photodetector, the competitive ELISA of APnEOs using HRP labeled APnEOs (HRP-APnEOs) was performed on magnetic microbeads on which surface an anti-APnEOs antibody had been immobilized. A typical sigmoidal calibration curve was obtained and the data were in good agreement with a numerical simulation, where the photocurrent of the OPD was plotted against the concentration of APnEOs, determined via the competitive ELISA. The detection limit of the immunoassay for APnEOs was approximately 2 and 4 ppb in batch and flow system, respectively.

Near-infrared absorbing squaraine dye with extended π conjugation for dye-sensitized solar cells

A NIR absorbing squaraine dye has been synthesized as a sensitizer for use in dye-sensitized solar cells (DSCs). Following computational calculations, a benz[cd]indole moiety was selected as an electron-rich heterocyclic component and condensed with indole-based emisquaraine bearing a carboxyl group, as an anchor for their immobilization on TiO2, to obtain an unsymmetrical squaraine with extended absorption due to its extensive π conjugation. The cells based on this dye exhibited a spectral response in the near-infrared region over 750 nm in addition to the visible region with a light absorption edge at 900 nm. The cells showed 1.1% efficiency and Incident Photon Current Efficiency (IPCE) of 36% at 800 nm.

One-Dimensional (1D) ZnO Nanowires Dye Sensitized Solar Cell

High ordered one-dimensional (1D) Zinc oxide (ZnO) nanowires were grown on FTO substrate by using the hydrothermal method. Nanowires structures were used as the wide band-gap semiconducting photo-electrode in dye sensitized solar cell (DSSCs). Solar cell made from ZnO nanowire at 50 nm radius and several tens micron lengths showed high solar conversion efficiency (eta) of 2.1% and incident photon current efficiency (IPCE) 35% using nanowire/N719 dye/I-/I3- electrolyte. We also compared Ru N719 dye and N3 dye on ZnO nanowire against each other in respect to solar conversion efficiency and IPCE measurements. In the case of the N3 dye on ZnO nanowire conversion efficiency (eta) of 1.32% and IPCE 23% were obtained under an illumination of 100 mW/cm2. It was found that the performance of the Ru N719 dyes was better than about 50% that of the N3 dye in ZnO nanowire dye-sensitized solar cells.

Planar and textured heterojunction organic photovoltaics based on chloroindium phthalocyanine (ClInPc) versus titanyl phthalocyanine (TiOPc) donor layers

Planar and textured heterojunction solar cells (OPVs) are reported for vacuum deposited chloroindium phthalocyanine (ClInPc)/C 60 heterojunctions, and their response compared to previously explored OPVs based on titanyl phthalocyanine (TiOPc)/C 60 heterojunctions. As for TiOPc/C 60 OPVs, the photoelectrical activity of ClInPc/C 60 OPVs extends well into the near infrared, with good activity out to ca. 900 nm. As-deposited ClInPc films (Phase I) produce open-circuit photopotentials, V OC as high as ca. 0.8 V (Phase I form of ClInPc), ca. 0.15 V larger than previously observed for Phase I TiOPc/C 60 OPVs. The offsets in frontier orbital energies ( E HOMO Pc – E LUMO C 60 ) revealed by UV-photoemission studies (UPS) are slightly smaller for ClInPc/C 60 versus TiOPc/C 60 heterojunctions, and the interface dipole contribution (shift in local vacuum level) to these offsets is in the opposite direction for ClInPc/C 60 versus TiOPc/C 60 heterojunctions, or missing altogether, suggesting differences in molecular interaction at the Pc/C 60 interface. Higher V OC values are correlated with lower reverse saturation currents, J o , for ClInPc/C 60, versus other Pc or pentacene/C 60 heterojunctions, suggesting weak intermolecular interactions at the ClInPc/C 60 interface and large barriers to dark charge injection. Solvent annealing of the ClInPc films enhances the near-IR response, and textures the Pc film, enhancing the Pc/C 60 interfacial contact area and the short-circuit photocurrent, J SC . J SC under AM 1.5 illumination conditions was estimated by integration of the incident photon current efficiency (IPCE) response, to compare relative power conversion efficiencies for the two different device types. The estimated efficiency of Phase I ClInPc/C 60 OPVs is ca. 2.6%. The estimated AM 1.5 efficiency of ClInPc/C 60 OPVs with solvent annealed Pc layers is estimated to be ca. 3.3%, arising from the extensive texturing achieved of the Pc layer, which nearly doubles J SC for the Phase II versus Phase I Pc films.

Bubble-like CdSe nanoclusters sensitized TiO 2 nanotube arrays for improvement in solar cell

Solar cells were fabricated using novel bubble-like CdSe nanoclusters sensitized highly ordered titanium oxide nanotube (TiO 2 NT) array, prepared by anodization technique. The CdSe sensitization of TiO 2 NT arrays was carried out by a chemical bath deposition method with freshly prepared sodium selenosufite, ammonium hydroxide and cadmium acetate dehydrate at different deposition times: 20, 40 and 60 min. The adsorption of CdSe nanoclusters on the upper and inner surface of the TiO 2 NT arrays has been confirmed by field emission scanning electron and transmission electron microscopes. The results show the variation in cell a performance with different deposition times (20, 40, and 60 min) of CdSe on TiO 2 NT arrays. The solar cell with CdSe, deposited for 60 min, shows reasonably high photovoltaic property compared to the reported results of similar studies. This solar cell shows the maximum photoelectric conversion efficiency of 1.56% (photocurrent of 7.19 mA/cm 2; photovoltage of 0.438 V; and fill factor of 49.5%) and average incident photon to current efficiency of 50.2%. The photocurrent, incident photon-current efficiency and electron lifetime have been improved due to the increase of covered area and size of bubble-like CdSe nanoclusters on TiO 2 NT arrays with the increase of deposition time.

Dye-sensitized solar cell using natural dyes extracted from spinach and ipomoea

This study used spinach extract, ipomoea leaf extract and their mixed extracts as the natural dyes for a dye-sensitized solar cell (DSSC). Spinach and ipomoea leaves were first placed separately in ethanol and the chlorophyll of these two kinds of plants was extracted to serve as the natural dyes for using in DSSCs. In addition, the self-developed nanofluid synthesis system prepared a TiO 2 nanofluid with an average particle size of 50 nm. Electrophoresis deposition was performed to let the TiO 2 deposit nanoparticles on the indium tin oxide (ITO) conductive glass, forming a TiO 2 thin film with the thickness of 11.61 μm. This TiO 2 thin film underwent sintering at 450 °C to enhance the compactness of thin film. Finally, the sintered TiO 2 thin film was immersed in the natural dye solutions extracted from spinach and ipomoea leaves, completing the production of the anode of DSSC. This study then further inspected the fill factor, photoelectric conversion efficiency and incident photon current efficiency of the encapsulated DSSC. According to the experimental results of current–voltage curve, the photoelectric conversion efficiency of the DSSCs prepared by natural dyes from ipomoea leaf extract is 0.318% under extraction temperature of 50 °C and pH value of extraction fluid at 1.0. This paper also investigated the influence of the temperature in the extraction process of this kind of natural dye and the influence of pH value of the dye solution on the UV–VIS patterns absorption spectra of the prepared natural dye solutions, and the influence of these two factors on the photoelectric conversion efficiency of DSSC.