Photoelectrochemical Solar Cells Research Articles

Thymus schimperi Ronniger plant flower extract dye-sensitized solar cells

The demand for energy is greatly increasing due to the world’s population growth and technological advancement. Natural dye-sensitized solar cells are attracting research as an alternative and renewable energy source due to their simple preparation technique, availability, cost effectiveness and environmental friendliness. In the present work, we have successfully fabricated dye-sensitized solar cells (DSSCs) from Thymus schimperi Ronniger plant flowers for the first time. The solvents used for extraction of the flower dye were deionized water and its mixture with ethanol. The T. schimperi Ronniger flower extract dye solutions and sensitized photoanodes were characterized by Fourier transform infrared and ultraviolet–visible techniques. The crystallinity of TiO2 films was analyzed by x-ray diffraction, and the films showed pure anatase phase behavior. The photoelectrochemical solar cell performance parameters, such as short circuit current density, open circuit voltage, fill factor and efficiency, were evaluated from current density–voltage measurements using a Keithley 2450 source meter. DSSCs sensitized with dye solution extracted by a mixture of water and ethanol showed better performance (1.37%) than those sensitized with dye solution extracted by deionized water alone (1.02%).

Novel Phenothiazine and Coumarin based Sensitizers: Design, Synthesis and Photoelectrochemical Application by Anchoring on CdS Nanowires

Novel metal-free organic dyes (E)-2-cyano-3-(10-(prop-2-yn-1-yl)-10H-phenothiazin-3-yl)acrylic acid (PPC) and (E)-2-cyano-3-(10-((1-((7-methyl-2-oxo-2H-chromen-4-yl)methyl)-1H-1,2,3-triazol-4-yl)methyl)-4a,10a-dihydro-10H-phenothiazin-3-yl)acrylic acid (PCTC) was synthesized and then anchored to 1D cadmium sulfide nanowires (1D CdS NWs) for application in photoelectrochemical dye-sensitized solar cell (DSSC). The 1D CdS nanowires were interconnected into a nanonetwork using solution chemistry in a straightforward and efficient manner. The UV-visible spectroscopy, cyclic voltammetry and density functional theory (DFT) were effectively employed to analyze the characteristics of PPC and PCTC. The sensitizer-anchored CdS nanowires have a broader range of light absorption in the UV-visible spectrum compared to bare CdS nanowires. The complete device has the assembly FTO, compact CdS, CdS nanowires, synthesized dye and counter electrode. In photovoltaic assessment, the PCTC and PPC devices yield 3.19 and 3.04 times, respectively, more efficiency than naked CdS nanowires under conventional sunshine illumination (100 mW/cm2, AM 1.5G). The obtained results provide strong evidence supporting the presence of rising external quantum efficiency (EQE) and show a high level of consistency with the optical tests.

The stability improvement of photoelectrochemical solar cells with Bi2S3 quantum dots sensitized photoanodes

Bi2S3, Bi2MoO6 and TiO2 composite photoanodes were fabricated using three different preparation routes to improve its photoelectrochemical (PEC) stability. The microstructure of three photoanodes are distinct significantly according to the results of XRD, SEM and TEM. The ordered TiO2 nanorod arrays (NRAs) and thinner Bi2MoO6 sheet crystals in flower-ball structure facilitate carrier transport and suppresses electron-hole recombination efficiently. The results of PEC tests indicate that the photoanode with Bi2MoO6 sheet crystals in flower-ball structure and TiO2 NRAs shows significant enhancement in PEC performance stability due to its ordered microstructure facilitating carrier transport and transfer and also good adherence of photoanode layer on FTO glass substrate. This photoanode in Bi2S3 quantum dots/Bi2MoO6@TiO2 NRAs structure exhibits satisfactory properties, achieving a PEC stability of 86.41% after 48 h.

Fabrication of single-step novel synthesis of ZnCd(S0.5Se0.5)2 thin films for photoelectrochemical (PEC) cell application

In our study, we use a new method called the arrested precipitation technique (APT) to create CdZn(SSe)2 (CZSS) thin films. We obtain samples at different deposition times, ranging from 2.5 to 4 h, and analyze the effects of deposition time on the opto-structural, morphological, compositional, and photoelectrochemical (PEC) solar cell properties. As a result, we find that the band gap energy increases from 2.366 to 2.60 eV with prolonged growth time, as shown by UV–Vis spectra. X-ray diffraction (XRD) analysis confirms that the crystal structure is hexagonal, with the crystallite size increasing from 76 to 93 nm. The dislocation density and microstrain, determined by the Scherrer formula, decrease from 1.72 to 1.14 lines m−2 and from 4.75 × 10−3 to 3.87 × 10−3 (lines m−2), respectively. These results are validated using the Williamson-Hall (WH) plot and size-strain plot. The average grain size, evaluated using the standard scale bar method in scanning electron microscopy (SEM), ranges from 80 to 150 nm across CZ1 to CZ4 samples. Transmission electron microscopy (TEM) images of CZ4 and CZ2 reveal particle sizes of 101 nm and 87 nm, respectively, while selected area electron diffraction (SAED) patterns confirm the polycrystalline nature of the material. Energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analyses confirm the presence of Cd, Zn, S, and Se elements in their intended stoichiometry. Notably, CZSS photoelectrodes deposited over 4 h show better performance in Photoelectrochemical cells (PEC), achieving the highest photoconversion efficiency (ɳ) at 2.33 %, as evidenced by J-V measurements.

Advancing Photoelectrochemical Systems: Unleashing the Remarkable Performance of In : SnO2/Nd4In5S13 for Sustainable Energy Applications

AbstractNeodymium Indium sulphide (Nd4In5S13) photoactive electrode was produced by spin‐coating for photoelectrochemical cell. The photoactive electrode is analysed for its crystalline, structural and elements makeup in addition to its optical and electrical responses. A 56 nm sized orthorhombic crystallite was found and geometrical compact structures were observed. The presence of chief elements with core levels of In3d, Nd4d and S2p were detected. The bandgap energy was found to be 4.1 eV. Electrochemical investigations were performed to evaluate the photoactive efficiency of the electrode. Photo‐cyclic voltammetry present a specific capacitance under illumination to be 570 Fg−1, as contrasting to 481 Fg−1 when in dark. A photocurrent density of 282 mA cm−2 was obtained from photo‐linear sweep voltammetry. It had also been discovered that the transient chronoamperometry provided a photocurrent density of 46.1 mA cm−2. Whereas electrical impedance spectroscopy presented internal resistance (Rs) to be 232 Ω. All scan rates show an increase in the specific capacitance of photo‐electrode when illuminated. The research created an effective photo‐electrode for renewable energy structures. It can be posited that the study presented a pragmatic photoelectrode, which had the potential to be employed in sustainable energy frameworks, including but not limited to photovoltaics, supercapacitors, and photoelectrochemical solar cells.

Fabrication of Dye Sensitized Solar Cell using Baccate (Berry) and Citrullus Lanatus (Water Melon) as Dye

The DSSC (dye-sensitized solar cell) is a photo electrochemical solar cell using redox mediator to transport electrons and become an attractive alternative to the widely used Si-based solar cell due to its low processing cost, ease of fabrication, moderate efficiency, and economical friendly. In this work DSSCs were fabricated using berry and watermelon as dye. Our results shows that DSSC with berry have higher efficiency than one with watermelon. The open circuit voltage (Voc), short circuit current, fill factors (FF), maximum power point (PMPP) and efficiency (η) for these cells were obtained and analyzed. The efficiencies for these cells are below prohibitive efficiency and this could be as a result of using ordinary glass because there were no availability of FTO. Further research work is ongoing with the use of FTO and comparative analysis will be carry out.

Novel 1,2,4-triazole sensitizers using N-arylsydnone as Synthon: Synthesis, Spectral, electrochemical, DFT and photovoltaic properties

Two novel 1,2,4-triazolone derivatized triphenylamine (TPA) and phenothiazine (PTZ) based metal-free organic dyes have been designed, synthesized and anchored on 1D CdS nanowires to serve as photoelectrochemical (PEC) dye-sensitized solar cells (DSSCs). Solution chemistry is employed simply and efficiently to link cadmium sulfide nanowires (CdS NWs) into a nano-network. Optical, electrochemical and density functional theory (DFT) have been well utilized to examine the properties of synthesized dyes (TPA and PTZ). In the visible range, sensitizer-anchored CdS NWs exhibit a wider region of light absorption referenced to naked CdS NWs. Comprehensive photovoltaic assessment showed that TPA and PTZ devices respectively showed IPCE 3.02 and 3.13 times more efficient than bare CdS NWs under standard sunlight (100 mW/cm2, AM 1.5G) illumination. The collected findings offer solid evidence for the existence of increasing external quantum efficiency (EQE) and exhibit good agreement with the optical experiments.

Efficiency Improvement of Photoelectrochemical Solar Cell Applications by Using Ternary Hybrid MoS2/g-C3N4/Cu2O

In this paper, molybdenum disulfide MoS2 was hybridized with graphene carbon nitrite (g-C3N4) and Cu2O in order to enhance the photoelectrochemical (PEC) activity and increase the light absorption range of Cu2O thin film. The melamine powder was poured in an empty container and then heated in a furnace to attain the powder. The ternary hetero-epitaxial growth was achieved by growing of MoS2/g-C3N4 on the Cu2O hybrid by a partial thermal oxidation process. The characteristics of MoS2/g-C3N4/Cu2O hybrid film were investigated through XRD, FT-IR and photoelectronchemistry-related measurements. The PEC behavior of the ternary hybrid electrode was investigated using current-voltage test under illumination. The efficiency calculated from current-voltage test under illumination shows that the presence of graphene carbon nitrite and molybdenum disulphide within the film networks, despite its low content, could stimulate substantial improvement in maximum photoconversion efficiency from 0.036% to 0.33%. This improvement is attributable to the enhancement of the electron-transferring proficiency upon the insertion of g-C3N4 and, MoS2 as confirmed by X-Ray Diffraction Analysis (XRD). The PEC test results signify that the photoelectrochemical activity of the MoS2/g-C3N4/Cu2O ternary hybrid is much higher than that of subtrate. The mechanisms accountable for the enhanced PEC behavior of the MoS2/g-C3N4/Cu2O ternary hybrid are discussed in detail.Keywords: Cuprous Oxide, J-V Characteristic, Hetero-structure, Photoelectrochemical, Thermal Oxidation.

Nano structured diatom frustules incorporated into TiO2 photoelectrodes to enhance performance of quasi-solid-state dye-sensitized solar cells

Diatom frustules are incorporated into multilayer photoelectrodes intending to enhance efficiency in dye-sensitized solar cells utilizing their light interaction properties. A specific, but ubiquitous in all oceans, pennate-type diatom frustules were used to form the composite layers. Single, double, and triple-layer photoelectrodes were constructed with pure TiO2 (control measurements) as well as with a TiO2/diatom frustule composite. The electrodes were prepared using TiO2 nanoparticles of two sizes (13 and 21 nm) and were analyzed using UV visible absorption and XRD spectra. The morphology of frustules and electrodes were analyzed using scanning electron microscopy. The performance for each photoanode configuration was measured by assembling photoelectrochemical solar cells fabricated with a Pt counter electrode and a gel polymer electrolyte that excludes volatile solvents. The efficiency of the control cell is 3.37%. After replacing the topmost TiO2 layer with a TiO2/diatom frustule composite layer, efficiency increases to 6.78%. This is an impressive efficiency enhancement of 101%. The short circuit current density of frustule-incorporated three-layer cells is 18.1 mA cm−1 while for the control cell it is 8.98 mA cm−1. The enhanced efficiency of cells made with TiO2/diatom frustule composite electrodes and a polyethylene oxide-based gel polymer electrolyte can be attributed to the improved light absorption by the photoanode due to optical scattering and light-trapping effects caused by the presence of diatom frustules. Frustules also can assist in enhancing dye adsorption by increasing the effective specific surface area of the composite photoelectrode due to their nanoporous structure.

Transferable Highly (001) Oriented Sb2Se3 Nanorod Films on Flexible Substrates for Innovative Optoelectronic Devices

AbstractThin films of antimony chalcogenides, Sb2X3 (X = S, Se, or SxSe1−x), comprised of (001) oriented nanorods are highly desirable for optoelectronic applications owing to their light trapping capacity and highly efficient charge transport along the optimally aligned quasi‐1D (Sb4X6)n ribbons. Here, highly (001) oriented Sb2Se3 nanorod (Sb2Se3NR) layers are obtained via a novel template growth method, and transfer these layers to functional substrates via a polymer‐assisted technique. Transferable layers overcome the current challenges associated with achieving oriented growth directly on the desired substrate. Using a combination of a low‐temperature processable SnO2 nanoparticle transport layer and encapsulation/etching techniques photodetector devices are fabricated with excellent electrical contact. The optimized transferred devices show broad range photoresponse with signal‐to‐noise ratios up to 105 and responsivities reaching 0.96 mA W−1. Importantly, access to low‐temperature processing enables the fabrication of flexible devices. Based on this platform, a proof‐of‐concept self‐powered flexible heart rate monitor is fabricated. The achievement of transferable Sb2Se3NR layers introduced in this work is expected to be readily applicable to generate new (001) Sb2Se3 device architectures that may otherwise not be achievable via direct deposition, with application in photoelectrochemical water splitting, battery electrodes, and solar cells.

(Invited) Solar Flow Batteries: Integrated Photoelectrochemical Solar Energy Conversion and Redox Flow Battery Systems

Due to the intermittent nature of sunlight, practical solar energy utilization systems demand both efficient solar energy conversion and inexpensive large scale energy storage. We have developed hybrid solar-charged storage devices called solar flow batteries (SFBs) that integrate photoelectrochemical solar cells with redox flow batteries (RFBs). In these devices, photoexcited carriers collected at the semiconductor-liquid electrolyte interface convert the redox couples to charge up the RFB without external electric bias; which can be discharged to generate the electricity when needed. By matching various silicon solar cells and tandem III-V solar cells (Chem 2018, 4, 2644) with various organic redox couples and optimizing the SFB device design, we improved their round trip solar-to-output electricity efficiency (SOEE) and eventually achieved a record SOEE of 20% with a 500-hour lifetime using high performance tandem perovskite/silicon solar cells (Nature Mater. 2020, 19, 1326). The design principles and the quantitative analysis model for voltage matching solar cells with RFBs (Acc. Chem. Res. 2020, 53, 2611) light up the pathways for achieving even better performance and stability yet maintaining a low cost, which would make these SFBs practical for standalone solar energy conversion and storage systems in remote off-grid locations.

Highly conducting flake-like CuS nanostructured counter electrode for photoelectrochemical solar energy conversion

Fabrication of platinum (Pt) free, low cost, environmentally friendly counter electrode is highly attractive for electrochemical solar energy conversion. In this report, highly conducting flake-like CuS nanostructured counter electrode has been prepared for photosensing study and semiconductor sensitized solar cell application. Flake-like CuS nanostructures were synthesized by sulfuration of CuO nanorods grown by hydrothermal process. Scanning electron microscopy and atomic force microscopy study confirmed the growth of flake-like CuS nanostructures on glass substrates. CuS nanoflakes were highly crystalline with hexagonal phase. The various electronic states of Cu and S in CuS nanoflakes were studied using X-ray photoelectron spectroscopy. Chemically grown CuS films were highly conducting and highest conducting film was obtained at 85°C growth temperature with sheet resistance ∼20.02±0.02Ω/sq. Photoelectrochemical solar cell (PEC) was fabricated using CdS decorated TiO2 nanorods as working electrode and CuS film as counter electrode. The short circuit current density, open circuit voltage and power conversion efficiency of the PEC device were found to be ∼4.8 A/m2, ∼0.38 V and ∼0.17%, respectively.

Hot carrier extraction from 2D semiconductor photoelectrodes

Hot carrier-based energy conversion systems could double the efficiency of conventional solar energy technology or drive photochemical reactions that would not be possible using fully thermalized, "cool" carriers, but current strategies require expensive multijunction architectures. Using an unprecedented combination of photoelectrochemical and insitu transient absorption spectroscopy measurements, we demonstrate ultrafast (<50 fs) hot exciton and free carrier extraction under applied bias in a proof-of-concept photoelectrochemical solar cell made from earth-abundant and potentially inexpensive monolayer (ML) MoS2. Our approach facilitates ultrathin 7 Å charge transport distances over 1cm2 areas by intimately coupling ML-MoS2 to an electron-selective solid contact and a hole-selective electrolyte contact. Our theoretical investigations of the spatial distribution of exciton states suggest greater electronic coupling between hot exciton states located on peripheral S atoms and neighboring contacts likely facilitates ultrafast charge transfer. Our work delineates future two-dimensional (2D) semiconductor design strategies for practical implementation in ultrathin photovoltaic and solar fuel applications.

In:SnO2/Yb2S3:Cu2S:ZnS: A Rare Earth Metal Sulfide‐Conjugated Transition Metal Sulfide Photoactive Electrode

Spin coating from a single source precursor is used to produce a transparent conductive electrode for a photoelectrochemical cell. Yb2S3:Cu2S:ZnS is discovered in the composite using X‐ray diffraction analysis with a crystallite size of 44 nm. Energy‐dispersive X‐ray analysis and X‐ray photoelectron spectroscopy reveal that the composite comprises Yb, Cu, Zn, and S with an optical bandgap of 2.49 eV. Electrical investigations in a photoelectrochemical cell are measured using cyclic voltammetry, linear sweep voltammetry, transient chronoamperometry (CA), and electrical impedance spectroscopy (EIS). Every experiment shows that the photocurrent density of the electrode is higher than when it is in the light. At all scan rates, light causes the photoelectrode's specific capacitance to increase. Specific capacitance is found to have a maximum value under illumination of 789 Fg−1 as opposed to 745 Fg−1 in the absence of a light source. The highest photocurrent density achieved by the electrode through CA is 23.5 mA. Rs value of 23.4 Ω is subsequently obtained by the EIS investigation. It might be stated that this work introduces a useful photoelectrode that can be used in renewable energy systems such as photovoltaics, supercapacitors, and photoelectrochemical solar cells.

Answering old questions with new techniques: Understanding performance-limiting factors in transition metal dichalcogenide photoelectrochemical solar cells

In the late 1970s and early 1980s, several research groups reported high-efficiency and stable photoelectrochemical solar cells based on transition metal dichalcogenides (TMDS; e.g., MoS 2 , WSe 2 , and MoSe 2 ) immersed in iodide/tri-iodide electrolytes. A consensus emerged that smooth crystals were necessary for high efficiency based on significant evidence that rough crystals with exposed edge sites produced lower photocurrents and fill factors. However, anecdotal observations in the literature hinted at significant performance variation among apparently smooth crystals with the possibility of highly active “hot” edge sites. This mini-review article is a case study on how spatially resolved photoelectrochemical techniques developed in the 2020s are answering old questions regarding the origin of performance variation in high efficiency n-type TMD|I – ,I 3 – |Pt photoelectrochemical solar cells.

Hybrid potentiodynamic/potentiostatic electrodeposition of thin and compact tin dioxide on indium tin oxide electrodes

Electrodeposition of conformal and compact SnO2 films on transparent conductive oxides (TCOs) has been hardly achieved thus limiting its application in fully solid solar cells such as those based in perovskite absorbers. Here are presented high-quality n-type semiconducting tin (VI) oxide (SnO2) thin films, successfully grown using a hybrid potentiodynamic/potentiostatic approach on both ITO and FTO coated glass substrates after a detailed optimization that included both annealing steps between eletrodepositions. A solution chemistry study together with a spectrophotometric analysis was useful to determine the one-hour time window of stability for the chosen electrolyte as source of tin. Formation mechanisms based in thermodynamic data and accumulated mass measurements using an electrochemical quartz crystal microbalance (EQCM) are discussed. From the EQCM study the growth rate of films was also estimated in good agreement with high resolution transmission electron microscopy (HR-TEM) analysis. Field emission scanning electron microscopy (FE-SEM) images and X-ray diffraction (XRD) data revealed that substrates are well-covered, crystalline, conformal and free of defects (e.g. without pinholes). The absence of these defects was also well supported by cyclic voltammetry measurements using the ferricyanide/ferrocyanide redox couple. XPS also confirmed the presence of Sn4+ in optimized films. From the optical properties, after carefully eliminating the influence of oscillations due to interference, a direct bandgap energy at 3.60 eV can be deduced. Another indirect bandgap energy at 3.30 eV can also be possible. The hybrid potentiodynamic/potentiostatic protocol to prepare SnO2 paves a way to prepare compact, transparent and well covering films suitable as electron transporting layer (ETL) for applications in both photoelectrochemical and solid-state solar cells.

Review of thin film deposition and techniques

The main aim of this paper is to review different thin film deposition techniques and their significance in photovoltaic applications. Chemical methods for preparing thin films are currently attracting due to their relative affordability, simplicity, and suitability for large-area deposition. Since these are low temperature techniques, they prevent substrate oxidation and corrosion and can be employed with a range of substrates, including insulators, semiconductors, and metals. These are gradual processes that enable crystallites to have improved grain structure and better orientation. All deposition techniques entail building a layer on an existing substrate with a thickness that can range from tens of Å to a millimetre depending on various working circumstances. Film growth may occur through ion-by-ion condensation of the materials on the substrates, depending on the deposition circumstances. Thin film deposition can be influenced by various parameters such as PH, temperature, deposition time etc are also described in the present article. Solar selective coatings, solar control, photoconductors, solid state and photoelectrochemical solar cells, optical imaging, hologram recording, optical mass memories etc. are some of the applications of metal chalcogenide films.

Successful 2D MoS2 nanosheets synthesis with SnSe grid-like nanoparticles: Photoelectrochemical hydrogen generation and solar cell applications

Preparing a two-dimensional (2D) lateral heterostructure film with n and p-type materials in the same film with high control distribution remains challenging so far. In this paper, a lateral heterostructure film based on 2D MoS2 nanosheets (NSs) with SnSe nanoparticles (NPs) “ SnSe/MoS2 ” is prepared via a facile one-step electrophoretic deposition method. MoS2 NSs are stacked vertically to form a film while SnSe NPs are incorporated to form nanoparticles of geometric grid-like inside the film. The film structure was confirmed through a scanning electron microscope. Such a heterostructure improves the performance of PEC hydrogen generation due to the fast separation of electron-hole pairs and hindering recombination. The short-circuit current density (JSC), as well as the open circuit voltage (VOC) of heterostructure film, reaches 1.75 mA cm−2 and 0.17 V, respectively, under a visible light illumination of 100 mW cm-2. The produced (Jph) values increase from 0.52 to 1.75 mA cm−2 under a light intensity ranging from 10 to 100 mW.cm−2, respectively. The grid-like structure of the SnSe/MoS2 heterostructure advantages its application for solar cells owing to the important potential difference that ensures the formation of p and n-type materials in the same film. This is the aim of our future work, where a complete synthesis of solar cells with high efficiency will be given, in which the p and n types of materials will face the sunlight directly.

Bi2S3-sensitized TiO2 nanorods by bottom-up approach for photoelectrochemical solar cell

Bi2S3-sensitized TiO2 nanorods by bottom-up approach for photoelectrochemical solar cell

(Invited) Efficient and Selective Electrocatalytic and Photoelectrochemical Conversion of Energy and Chemicals

Due to the intermittent nature of most renewable energy sources (such as solar and wind), practical large scale renewable energy utilization demands both efficient energy conversion and large scale energy storage or alternative usage. Earth-abundant but highly active and selective electrocatalysts are needed to enable efficient and sustainable production of fuels and chemicals using electrocatalytic and photoelectrochemical (PEC) energy conversion. We developed earth-abundant electrocatalysts for highly efficient hydrogen evolution reaction (HER) and oxygen evolution (OER). We recently combined computations and experiments to develop metal compounds as selective catalysts for two-electron oxygen reduction reaction (2e- ORR) to produce hydrogen peroxide (H2O2) and the subsequent electro-Fenton process for upgrading biomass molecules. We have integrated these earth-abundant electrocatalysts with efficient semiconductor materials to demonstrate efficient photoelectrochemical hydrogen generation systems. We also developed high performance hybrid solar-charged storage devices that integrate photoelectrochemical solar cells and redox flow batteries (RFBs). In these integrated solar flow batteries (SFBs), solar energy is absorbed by semiconductor electrodes to directly charge up the redox couples without external electric bias. Such charged redox molecules can then be either discharged to generate the electricity when needed or used to produce fuels and chemicals.