Dye-sensitized Solar Cells Devices Research Articles

Effect of TiCl4‐based TiO2 compact and blocking layers on efficiency of dye‐sensitized solar cells

The effect of the number and arrangement of TiO2‐based photoanode layers on the efficiency of dye‐sensitized solar cells (DSSCs) was investigated. Compact, mesoporous, and blocking layers of TiO2 were prepared to form monolayer, bilayer, and trilayer photoanodes. Compact and blocking TiO2 layers were prepared using dip‐coating technique, whereas the doctor‐blade method was employed to prepare TiO2 paste layers using nanoparticles prepared by the sol–gel method. The crystalline structure of photoanodes was characterized by X‐ray diffraction (XRD) measurements and their morphology and thickness were characterized by the scanning electron microscopy (SEM) technique. The photovoltaic performance of constructed DSSC devices was investigated and the optimum arrangement was identified and explained in terms of dye loading enhancement and recombination reduction at the fluorine‐doped tin oxide (FTO)/electrolyte interface.

Rapid, 5 min, low temperature aqueous platinization for plastic substrates for dye-sensitized solar cells

This paper reports a rapid (5 min), low temperature (120 °C) method to platinize the counter electrodes of dye-sensitized solar cell (DSC) devices. This new method uses aqueous solutions and is based on chemical bath deposition of an activating Pd layer followed by Pt only using H2 gas as the reductant. This method has been tested on flexible, plastic substrates (indium tin oxide-coated polyethylene terephthalate or polyethylene naphthalate, ITO-PET or ITO-PEN, respectively). We report device efficiencies up to 7.2% on ITO-PET which is comparable to devices made using high temperature (400 °C) processing on rigid, fluoride-doped tin oxide (FTO) glass counter electrodes. The method is scalable and suitable for continuous roll-to-roll production.

Characteristics of transparent indium zinc oxide electrode prepared on poly(ethylene naphthalate) by radio frequency magnetron sputtering for flexible dye-sensitized solar cells

In this study, for the use as a transparent electrode in flexible dye-sensitized solar cells (DSSCs), the indium zinc oxide (IZO) thin films on unheated poly(ethylene naphthalate) (PEN) substrate in pure argon ambient by radio frequency (RF) magnetron sputtering method have been prepared, and their characteristics with respect to RF power were investigated. It has been found that the IZO films on PEN show a dense amorphous structure and the surface microstructure of the films is hardly sensitive to the RF power. The electrical and optical properties of RF magnetron sputtered IZO thin films on PEN are strongly influenced by RF power. At a RF power of 60 W, it is obtained the IZO thin film with the sheet resistance of about 7.65 Ω/sq. and optical transmittance of about 80% at 550 nm wavelength, resulting in the highest value for figure of merit. The flexible DSSC device embedded with the transparent IZO electrode deposited at 60 W shows the high power conversion efficiency, which is the value of 4.7% under simulated air mass 1.5 irradiation.

Synthesis and DSSC Applications of Ru(II) Complexes Bearing Benzimidazole Type Ligands

In this study, the synthesis of 7 Ru(II) polypyridine complexes (C1–7) and their characterization by FT-IR, UV–Vis, 1H-NMR and ESI–MS spectroscopic methods have been reported. The use of the complexes as photosensitizers in dye-sensitized solar cells (DSSCs) has been investigated. The photovoltaic characteristics of the fabricated DSSC devices were examined under 1.5 G solar simulation and TiO2 was used as a semiconductor. Absorption and emission spectra of the complexes were examined, cyclic voltammograms of the Ru complexes were performed and HOMO–LUMO energy levels were calculated. Thus, electrochemical properties of the complexes and the energy diagrams, which shows the charge transfer characteristics of the complexes were studied. The alterations in the current–potential characteristics of the Ru sensitizers by modifications in ligands have been investigated. The effects of the substitutions on ligands are evaluated and power conversion efficiency value up to half of the reference sensitizer was obtained by C6 complex.

Effect of Different π-Conjugated Dyes Containing 4,5-Diazafluorenone-9- Hydrazone on The Performance of Dye-Sensitized Solar Cells

In this study, two ligands and their ruthenium complexes are synthesized and their photovoltaic properties for dye-sensitized solar cells (DSSCs) of new substances substituted by 4,5-diazafluorenone-9-hydrazone groups is investigated. The structures of the compounds are determined by FTIR, UV-Vis, HNMR, CNMR, and MS spectroscopic techniques. The photovoltaic and electrochemical properties of these compounds are investigated and the applicability in DSSCs as photo sensitizers is studied. Photovoltaic cell efficiencies (PCEs) of the devices are in the range 0.08-1.54% under simulated AM 1.5 solar irradiation of 100 mW/cm2, and the highest open-circuit voltage (Voc) reaches 0.43 V. When the photovoltaic performance of the DSSC devices is compared, it indicates that PCEs assume the following: P1–Ru > > P2–Ru > P1 > P2. The PCE value of 1.54% is obtained with DSSC based on P1–Ru under AM irradiation (100 mW/cm2). DSSC based on the P1–Ru produced efficiency of 1.54% whereas DSSC-based P1 exhibits the device performance with an efficiency of 0.08% under illumination. These results suggest that a larger π-conjugated bridge and a richer electron donor of P1–Ru are beneficial for the photovoltaic performance of DSSC.

Low temperature sintering of aqueous TiO2 colloids for flexible, co-sensitized dye-sensitized solar cells

Colloidal TiO2 films have been prepared using a binder-free aqueous paste with Degussa P25 and hexafluorotitanic acid (H2TiF6), which was optimised for different substrates. Dye-sensitized solar cells (DSSC) fabricated using this paste were sintered at (ca. 393 K) and efficiencies (η) of 3.0, 4.2 and 6.1% were measured for devices using titanium foil (ca. 1 mm thickness), indium-doped tin oxide on polyethylene terephthalate (ITO-PET), and for co-sensitized devices on fluorine-doped tin oxide (FTO) glass substrates, respectively. Electrochemical impedance measurements show that the charge transport resistance is less consistent for devices fabricated at low sintering temperature (ca. 393 K) by comparison to devices sintered at 773 K. These measurements correlate with the increased variation in device efficiency (η) for low temperature sintered DSSC devices.

Homo- and Heterodimeric Dyes for Dye-Sensitized Solar Cells: Panchromatic Light Absorption and Modulated Open Circuit Potential.

The design of dyes for panchromatic light absorption has attracted much attention in the field of dye-sensitized solar cells (DSSCs). An approach to enhance panchromatic light absorption utilizes mixtures of complementary light-absorbing dyes as well as dyes with specific anchoring groups that facilitate interfacial charge transfer with TiO2 . Dipole-dipole interactions between the dye molecules on the surface broaden the spectrum, which results in decreased DSSC device performance. However, controlled aggregation of dyes results in broadening the spectral profile along with enhanced photocurrent generation. To control the dye-dye interaction, dimeric dyes with different dipole lengths D1 -Dsq , Dsq -Dsq were systematically designed and synthesized. The photophysical and electrochemical properties were evaluated and the EHOMO and ELUMO levels were determined; these energy levels determines the electron injection from ELUMO of the dye to ECB of TiO2 and regeneration of oxidized dye by the electrolyte, respectively. The absorption spectra of Dsq -Dsq , D1 -Dsq were broadened in solution compared to model dye Dsq ; this indicates that the dye-dye interaction is prominent in solution. In D1 -Dsq excitation energy transfer between photoexcited D1 and Dsq was explained by using Förster resonance energy transfer (FRET). The homodimeric dye showed a device performace of 2.8 % (Voc 0.607, Jsc 6.62 mA/cm2 , ff 69.3 %),whereas the heterodimeric dye D1 -Dsq showed a device performance of 3.9 % (Voc 0.652 V, Jsc 8.89 mA/cm2 , ff 68.8 %). The increased photocurrent for D1 -Dsq is due to the panchromatic IPCE response compared to Dsq -Dsq . The increased Voc is due to the effective passivation of the TiO2 surface by the spirolinker, and the effective dipole moment that shifts the conduction band on TiO2 . Hence, the open circuit potential, Voc , for the devices prepared from Dsq , D1 -Dsq and Dsq -Dsq were systematically modulated by controlling the intermolecular π-π and intramolecular dipole-dipole interactions of the dimeric dyes.

Influence of CdS Morphology on the Efficiency of Dye-Sensitized Solar Cells.

Cadmium sulfide (CdS) used in dye-sensitized solar cells (DSSCs) is currently mainly synthesized by chemical bath deposition, vacuum evaporation, spray deposition, chemical vapor deposition, electrochemical deposition, sol–gel, solvothermal, radio frequency sputtering, and hydrothermal process. In this paper, CdS was synthesized by hydrothermal process and used with a mixture of titanium dioxide anatase and rutile (TiO2(A+R)) to build the photoanode, whereas the counter electrode was made of nanocomposites of conductive polymer polyaniline (PANI) and multiwalled carbon nanotubes (MWCNTs) deposited on a fluorine-doped tin oxide substrate. Two morphologies of CdS have been obtained by using hydrothermal process: branched nanorods (CdSBR) and straight nanorods (CdSNR). The present work indicates that controlling the morphology of CdS is crucial to enhance the efficiency of DSSCs device. Indeed, the higher power conversion energy of 1.71% was achieved for a cell CdSBR–TiO2(A+R)/PANI–MWCNTs under 100 mW/cm2, whereas the power conversion energy of 0.97 and 0.83% for CdSNR–TiO2(A+R)/PANI–MWCNTs and TiO2(A+R)/PANI–MWCNTs, respectively. Therefore, by increasing the surface to volume ratio of CdS nanostructures and the crystallite size into those structures opens the way to low-cost chemical production of solar cells.

Visible Light Absorption and Photo-Sensitizing Characteristics of Natural Dye Extracted from Mangosteen Pericarps Using Different Solvents

Dye is an important factor in determining the efficiency of a dye-sensitized solar cell (DSSC) device. One of the dyes derived from natural resource is anthocyanin. At the same time, one of the natural resources containing anthocyanin is a tropical plant called mangosteen. In this work, the characteristics of anthocyanin extracted from mangosteen pericarps using different solvents have been examined. The anthocyanin was extracted from mangosteen pericarps using various different solvents, i.e. dry ethanol, ethanol containing 1% HCl, and ethanol containing 1% acetic acid. Absorption characteristic of dye extracted from different solvents was determined using ultraviolet-visible spectroscopy (UV-Vis). Fourier transform infrared (FTIR) was used to examine the functional groups of the extracted dye. Visible light absorption and photo-sensitizing characteristics of the extracted natural dye were then investigated through their applications in a DSSC device. The results from infrared characterization showed that all of the extracted dyes indicated the same tendency with the characteristic of anthocyanin. At the same time, the UV-Vis examination revealed that the dye extracted using solvent HCl 1% acidified ethanol was found to have a visible light absorption at a wavelength of 533 nm. This result indicated that HCl 1% acidified ethanol was the best solvent to extract anthocyanin from mangosteen pericarps. The activity of the DSSC device sensitized using the extracted dye through a photocurrent-voltage examination showed a power conversion efficiency of 0.23% and 0.18% for the device using the commercial dye and the mangosteen extracted dye, respectively. This result is quite convincing and promising for the next DSSC device development using natural dye extracted from mangosteen pericarps.

Indenoquinaldine-Based Unsymmetrical Squaraine Dyes for Near-Infrared Absorption: Investigating the Steric and Electronic Effects in Dye-Sensitized Solar Cells.

A series of near-infrared (NIR)-responsive unsymmetrical squaraine dyes (ISQ1-3) incorporating a fused indenoquinaldine-based donor have been designed and synthesized. C12 alkyl chains were incorporated at the sp3 -hybridized carbon center of the indene unit of the indenoquinaldine in an out-of-plane orientation to control dye aggregation on the surface of titanium dioxide, and indole (ISQ1), benzo[e]indole (ISQ2), and quinoline (ISQ3) moieties were included as the donor component bearing the anchoring carboxy group to extend the absorption in the NIR region and to systematically study the effect of the electronic modification on the performance of dye-sensitized solar cells (DSSC). All the dyes exhibit intense absorption (ϵ≥105 m-1 cm-1 ) in the NIR region, and the dye-adsorbed TiO2 films exhibit broad panchromatic absorption. The incident photon-to-current efficiency (IPCE) spectrum of the ISQ3-based DSSC device displays a panchromatic IPCE response up to 880 nm. Additionally, the ISQ3-sensitized device provides the best efficiency of 4.15 % with a short circuit current density (JSC ) of 10.02 mA cm-2 , open-circuit voltage (VOC ) of 0.58 V, and fill factor (ff) of 72 % in the presence of 10 equivalents of 3α,7α-dihydroxy-5β-cholanic acid (CDCA). Electrochemical impedance spectroscopy analysis showed attenuated charge recombination in the ISQ3-sensitized DSSC, which contributes to its higher value of VOC compared with the other dyes.

Research Progress on Photosensitizers for DSSC.

Dye sensitized solar cells (DSSC) are considered one of the most promising photovoltaic technologies as an alternative to traditional silicon-based solar cells, for their compatibility with low-cost production methods, their peculiar optical and mechanical properties and the high indoor efficiency. Photosensitizers represent one of the most important components of a DSSC device and probably the most thoroughly investigated in the last twenty years, with thousands of dyes that have been proposed and tested for this kind of application. In this review we aimed to provide an overview of the three main classes of DSSC photosensitizers, namely ruthenium(II) polypyridyl complexes, Zn-porphyrin derivatives and metal-free organic dyes. After a brief introduction about the architecture and operational principles of a DSSC and the state of the art of the other main components of this type of device, we focused our discussion on photosensitizers. We have defined the numerous requirements DSSC photosensitizers should satisfy and have provided an overview of their historical development over the years; by examining specific dyes reported in the literature, we attempted to highlight the molecular design strategies that have been established for the optimization of their performance in real devices both in terms of efficiency (which recently reaches an outstanding 14.3%) and operational stability. Finally, we discussed, in the last section, the possible future developments of this intriguing technology.

Characteristics of PANi/rGO Nanocomposite as Protective Coating and Catalyst in Dye-sensitized Solar Cell Counter Electrode Deposited on AISI 1086 Steel Substrate

One of the possibilities to mass-produce dye-sensitized solar cell (DSSC) device is if it could be embedded to the area atop metal roof. However, the use of metal substrate is constrained by the corrosion caused by the electrolyte solution used in the DSSC device such as iodide/tri-iodide (I-/I3-). In this study, we propose the utilization of polyaniline/reduced graphene oxide (PANi/rGO) nanocomposite as protective coating and at the same time as catalyst for the DSSC counter electrode on AISI 1086 steel substrates. The work was started by synthesizing PANi and rGO and assembling the PANi/rGO nanocomposite in a DSSC device. The characterization was performed using X-ray diffraction (XRD) for crystal structure, infrared (FTIR) for functional groups, scanning electron microscope (SEM) for surface morphology, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) for corrosion testing, and semiconductor parameter analyzer (SPA) for the DSSC device performance. The result showed that the decrease of corrosion rates in AISI 1086 steel was proportional to the rGO concentrations in PANi/rGO nanocomposites. The lowest corrosion rate was obtained at the highest rGO composition, i.e. PANi/rGO 8 wt% with corrosion rate (CR) of 0.2 mm/year and protection efficiency of 80.3 %. The DSSC performance test revealed that PANi/rGO composite could be used as an alternative catalyst for I-/I3- based redox electrolyte in the DSSC solar cell applications in replacement for platinum. The highest power conversion efficiency of 5.38 % was obtained from PANi/rGO 4 wt%.

Interfacial electron transfer yields in dye-sensitized NiO photocathodes correlated to excited-state dipole orientation of ruthenium chromophores

Interface dynamics of nanocrystalline NiO thin films sensitized with two ruthenium polypyridyl chromophores have been investigated to examine the influence that excited-state dipole orientation and the position of the bipyridine radical formed in the charge-separated state have on interfacial electron transfer yields. In ultrafast transient absorption experiments, the charge separated state is observed on the nanosecond timescale for the trifluoromethyl-substituted chromophore, [Ru(flpy)2(dcb)]2+ (flpy = 4,4′-bis(trifluoromethyl)-2,2′-bipyridine, dcb = 4,4′-dicarboxy-2,2′-bipyridine), but not for [Ru(bpy)2(dcb)]2+ (bpy = 2,2′-bipyridine). Differences are attributed to the positioning of the bipyridine radical formed in the charge separated state; for [Ru(flpy)2(dcb)]2+, the electron is localized on the flpy ligand distal to the surface, whereas for [Ru(bpy)2(dcb)]2+, the electron is localized on the dcb ligand, proximal to the NiO surface. Enhanced photovoltaic performance is observed for dye-sensitized solar cell devices prepared with [Ru(flpy)2(dcb)]2+, demonstrating that enhanced charge separation can be correlated with device efficiency.

Spin-Doctoring Cobalt Redox Shuttles for Dye-Sensitized Solar Cells.

A new low-spin (LS) cobalt(II) outer-sphere redox shuttle (OSRS) [Co(PY5Me2)(CN)]+, where PY5Me2 represents the pentadentate ligand 2,6-bis(1,1-bis(2-pyridyl)ethyl)pyridine, has been synthesized and characterized for its potential application in dye-sensitized solar cells (DSSCs). Introduction of the strong field CN- ligand into the open axial coordination site forced the cobalt(II) complex, [Co(PY5Me2)(CN)]+, to become LS based upon the complex's magnetic susceptibility (1.91 ± 0.02 μB), determined by the Evans method. Interestingly, dimerization and subsequent cobalt hexacyanide cluster formation of the [Co(PY5Me2)(CN)]+ monomer was observed upon long-term solvent exposure or addition of a supporting electrolyte for electrochemical characterization. Although long-term stability of the [Co(PY5Me2)(CN)]+ complex made it difficult to fabricate liquid electrolytes for DSSC applications, short-term stability in neat solvent afforded the opportunity to isolate the self-exchange kinetics of [Co(PY5Me2)(CN)]2+/+ via stopped-flow spectroscopy. Use of Marcus theory provided a smaller than expected self-exchange rate constant of 20 ± 5.5 M-1 s-1 for [Co(PY5Me2)(CN)]2+/+, which we attribute to a Jahn-Teller effect observed from the collected monomer crystallographic data. When compared side-by-side to cobalt tris(2,2'-bipyridine), [Co(bpy)3]3+, DSSCs employing [Co(PY5Me2)(CN)]2+ are expected to achieve superior charge collection, which result from a smaller rate constant, ket, for recombination based upon simple dark J- E measurements of the two redox shuttles. Given the negative redox potential (0.254 V vs NHE) of [Co(PY5Me2)(CN)]2+/+ and the slow recombination kinetics, [Co(PY5Me2)(CN)]2+/+ becomes an attractive OSRS to regenerate near IR absorbing sensitizers in solid-state DSSC devices.

Quinoxaline-Based Dual Donor, Dual Acceptor Organic Dyes for Dye-Sensitized Solar Cells

A novel metal-free quinoxaline-based molecular framework with a dual donor and dual acceptor (DD-π-AA) motif has been introduced. Four sensitizers (AP6, AP8, AP9, and AP12) have been synthesized and fully characterized via UV–Vis absorption, cyclic voltammetry, density functional theory (DFT) calculations, time-correlated single photon counting (TCSPC), and in dye-sensitized solar cell (DSC) devices. Structural modifications to both the donor and acceptor/anchor regions were evaluated via structure–property relationships without altering the quinoxaline π-bridge. Through careful dye design, a broadly absorbing near-infrared (NIR) sensitizer extending electricity production to 800 nm is realized in DSC devices. Ground- and excited-state oxidation potentials were measured to show energetically favorable charge transfer events. Importantly, the dye structure was found to have a strong influence on dye energetics in different environments with structural elements allowing for either similar or dramatically different solution versus film measurements. The DSC device electrolyte was also found to have a significant influence on dye energetics as well. Electron transfer events were probed for each dye with DSC device measurements and with TCSPC studies. The results are correlated to the dye structures.

Efficient and Stable Dye-Sensitized Solar Cells Based on a Tetradentate Copper(II/I) Redox Mediator.

The identification of an efficient and stable redox mediator is of paramount importance for commercialization of dye-sensitized solar cells (DSCs). Herein, we report a new class of copper complexes containing diamine-dipyridine tetradentate ligands (L1 = N, N'-dibenzyl- N, N'-bis(pyridin-2-ylmethyl)ethylenediamine; L2 = N, N'-dibenzyl- N, N'-bis(6-methylpyridin-2-ylmethyl)ethylenediamine) as redox mediators in DSCs. Devices constructed with [Cu(L2)]2+/+ redox couple afford an impressive power conversion efficiency (PCE) of 9.2% measured under simulated one sun irradiation (100 mW cm-2, AM 1.5G), which is among the top efficiencies reported thus far for DSCs with copper complex-based redox mediators. Remarkably, the excellent air, photo, and electrochemical stability of the [Cu(L2)]2+/+ complexes renders an outstanding long-term stability of the whole DSC device, maintaining ∼90% of the initial efficiency over 500 h under continuous full sun irradiation. This work unfolds a new platform for developing highly efficient and stable redox mediators for large-scale application of DSCs.

Transparency, moisture barrier property, and performance of the alternative solar cell encapsulants based on PU/PVDC blend reinforced with different types of cellulose nanocrystals

Two different types of cellulose nanocrystals, derived from water hyacinth fibers and microfibrillated cellulose (MFC), were prepared using an acid hydrolysis treatment. These cellulose nanocrystals (CNCs) were further used as barrier enhancing fillers for polyurethane (PU) blended with 25 wt% of poly(vinylidene dichloride) (PVDC). The aim of this study was to investigate the effects of types and concentration of CNCs on mechanical, optical and barrier properties of polymer composite films. The feasibility of applying the obtained composite films as an encapsulating material for enhancing the lifetime of dye sensitized solar cells (DSSC) was also of interest. The acid hydrolysis of the MFC-yielded rod-shaped cellulose nanocrystals (CNCm) while the acid-hydrolyzed water hyacinth led to a formation of spherical-shaped cellulose nanocrystals (CNCw). Regardless of the types of CNCs, the optical transparency of the composite films was maintained well above 60%. According to results in this study, the most efficient film with the lowest water vapor transmission rate of 0.0517 g m−2 day−1 was the PU/PVDC film reinforced with 0.1 wt% of CNCm. The encapsulants made from this composite could prolong the lifetime of the DSSC devices for up to 14 days, with the normalized PCE value of 0.78. Overall, this work showed that the considerations of the barrier properties of the polymer encapsulants alone are insufficient to ensure that the system would be effective. An interfacial adhesion between the encapsulants and the electrodes, as well as some side reactions between polymers and chemicals inside the fabricated cell, should also be taken into account.

A Smart Flexible Solid State Photovoltaic Device with Interfacial Cooling Recovery Feature through Thermoreversible Polymer Gel Electrolyte.

Quasi-solid-state dye-sensitized solar cells (DSSCs) fabricated with lightweight flexible substrates have a great potential in wearable electronic devices for in situ powering. However, the poor lifespan of these DSSCs limits their practical application. Strong mechanical stresses involved in practical applications cause breakage of the electrode/electrolyte interface in the DSSCs greatly affecting their performance and lifetime. Here, a mechanically robust, low-cost, long-lasting, and environment-friendly quasi-solid-state DSSC using a smart thermoreversible water-based polymer gel electrolyte with self-healing characteristics at a low temperature (below 0 °C) is demonstrated. When the performance of the flexible DSSC is hindered by strong mechanical stresses (i.e., from multiple bending/twisting/shrinking actions), a simple cooling treatment can regenerate the electrode/electrolyte interface and recover the performance close to the initial level. A performance recovery as high as 94% is proven possible even after 300 cycles of 90° bending. To the best of our knowledge, this is the first aqueous DSSC device with self-healing behavior, using a smart thermoreversible polymer gel electrolyte, which provides a new perspective in flexible wearable solid-state photovoltaic devices.

Optimization of Ni2+/Ni3+ ratio in reduced graphene oxide/nickel oxide nanohybrids for platinum free dye sensitized solar cells

A strategy has been explored to design a novel network of reduced graphene oxide (rGO)/nickel oxide (NiO) nanohybrids with optimized Ni2+/Ni3+ ratio for the fabrication of compact, flexible, and large area Pt-free dye sensitized solar cells (DSSCs). The rGO/NiO nanohybrids were synthesized by a hydrothermal method and characterized by field emission scanning electron microscopy, Brunauer-Emmett-Teller analysis, X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform infrared spectroscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. These studies demonstrate that the rGO/NiO nanohybrids with Ni2+ rich species show high catalytic activity toward the I¯/I3¯ redox reaction. This led to the fabrication of improved DSSCs with power conversion efficiency as high as 3.69% with these nanohybrids as counter electrodes in comparison with DSSC devices containing counter electrodes based on rGO (1.71%) and NiO (0.75%).

Enhancing the efficiency of quasi-solid-state dye-sensitized solar cells by adding bis(trifluoromethane)sulfonimide lithium salt and camphorsulfonic acid to gel-based electrolytes

In this study, gel-based electrolytes were produced by mixing a liquid-based electrolyte with poly(methyl methacrylate) (PMMA), which served as a gelator to enhance the stability of the electrolytes and dye-sensitized solar cells (DSSCs). Furthermore, bis(trifluoromethane)sulfonimide lithium salt (LiTFSI) and camphorsulfonic acid (C10H16O4S) were separately added to the gel-based electrolytes. The results indicate that adding LiTFSI and C10H16O4S to the gel-based electrolytes effectively enhanced the device efficiency. In particular, the device with the 1:1 + 0.1 M LiTFSI gel-based electrolyte exhibited the optimal efficiency (7.33%), which was higher than that observed in the device with the liquid-based electrolyte. The results also proved that the DSSC devices with the gel-based electrolytes exhibited a longer stability. Therefore, using optimized gel-based electrolytes can enhance the power conversion efficiency and stability of DSSC devices.