Field Of Dye-sensitized Solar Cells Research Articles

Design and fabrication of NiCo2S4@rGO as an efficient Pt free triiodide reducing agent for dye-sensitized solar cell application

Exploiting efficient Pt-free counter-electrode materials with low cost and highly catalytic property is a hot topic in the field of Dye-sensitized solar cells (DSCs). Here, NiCo2S4/reduced graphene oxide (RGO) was prepared via an economical hydrothermal ynthesis route, and the as-prepared composite exhibited comparable electrocatalytic property with the conventional Pt electrode as the counter-electrode. Enhanced optoelectronic, optical and structural characteristics have been attained over the constructed heterojunction. Band gap energy of NiCo2S4 (2.35 eV) was suppressed to 2.11 eV owing to its supporting with 10 wt.% rGO bringing about upgraded absorption of visible light. Electrochemical studies confirmed the synergetic effect of nickel and cobalt ions with the high electrical conductive rGO networks that enhance the electrocatalytic activity of NiCo2S4 nanostructures. The efficiency achieved for the NiCo2S4@rGO counter electrode (CE) based DSSC is 8.17%, which is remarkably higher than that of pristine NiCo2S4 (7.31%), and Pt (7.14%) under the same experimental conditions. In outline, given their innovative synthesis approach, affordability, and remarkable electrocatalytic attributes, the newly developed NiCo2S4@rGO counter electrodes stand out as potent contenders in future dye-sensitized solar cell applications.

Performance evaluation of ruthenium complexes and organic sensitizers in ZnO-based dye-sensitized solar cells

Ruthenium (Ru) dyes are a well-known player in the field of dye-sensitized solar cells (DSSCs) due to their high efficiency and excellent stability. Their properties and complexes have been studied for almost three decades. Although these sensitizers show better performances, their high cost makes these third-generation solar devices less economical. Organic dyes have recently been explored as an alternative to Ru-based dyes due to their easy and low-cost synthesis. A comparative performance evaluation of Ru complexes and dicyanoisophorone and rhodanine organic dyes in ZnO-based DSSCs is here reported. All the Ru complexes showed better performance in comparison to organic dyes except R-4. Among the Ru sensitizers, R-3 exhibited the highest efficiency of 1.21% followed by R-2, which is attributed to the presence of several anchoring groups such as carboxyl, nitro and amine. However, the presence of more nitrogen-based groups has drastically reduced the performance as observed for R-4, which is the least performing dye among the Ru-based ones. On the contrary, organic sensitizers S-06 and P-4 revealed to be less efficient with respect to R-3 owing to the presence of only one anchoring group and weak photoanode/dye interaction.

Fully Additively Manufactured Counter Electrodes for Dye-Sensitized Solar Cells.

In dye-sensitized solar cells (DSSCs), the counter electrode (CE) plays a crucial role as an electron transfer agent and regenerator of the redox couple. Unlike conventional CEs that are generally made of glass-based substrates (e.g., FTO/glass), polymer substrates appear to be emerging candidates, owing to their intrinsic properties of lightweight, high durability, and low cost. Despite great promise, current manufacturing methods of CEs on polymeric substrates suffer from serious limitations, including low conductivity, scalability, process complexity, and the need for dedicated vacuum equipment. In the present study, we employ and evaluate a fully additive manufacturing route that can enable the fabrication of CEs for DSSCs in a high-throughput and eco-friendly manner with improved performance. The proposed approach sequentially comprises: (1) material extrusion 3-D printing of polymer substrate; (2) conductive surface metallization through cold spray particle deposition; and (3) over-coating of a thin-layer catalyzer with a graphite pencil. The fabricated electrodes are characterized in terms of microstructure, electrical conductivity, and photo-conversion efficiency. Owing to its promising electrical conductivity (8.5 × 104 S·m-1) and micro-rough surface structure (Ra ≈ 6.32 µm), the DSSCs with the additively manufactured CEs led to ≈2.5-times-higher photo-conversion efficiency than that of traditional CEs made of FTO/glass. The results of the study suggest that the proposed additive manufacturing approach can advance the field of DSSCs by addressing the limitations of conventional CE manufacturing platforms.

Alternative Sources of Natural Photosensitizers: Role of Algae in Dye-Sensitized Solar Cell

In this paper, the potential of marine algae to act as sensitizers is systematically studied and presented. We aim to find a feasible financial strategy to enhance the global efficiency of dye-sensitized solar cells (DSSC). Algae are mainly composed of chlorophylls, carotenoids, flavonoids, and Betalains, which are essential pigments that confer unique characteristics that are required in natural sensitizers. Therefore, this review aims to unveil and understand the underlying mechanism between algae pigments and photoelectrodes and to conduct a comprehensive analysis to determine the effect of algae dye on light absorption efficiency and electron transport. The structural, morphological, optical, and electrochemical impedance properties are deeply analyzed, and we show the current opportunities for natural dyes to be used in energy technologies through DSSC. A comparison of several bibliographic sources dealing with DSSC based on algae provided a general overview of the improvements in factors such as the recombination times, the filling factor, and the Voc values. The contributions of this paper relate to the conversion efficiency and future applications in the DSSC field. Finally, this review exemplifies that the nature of the pigment affects the photophysical properties of the cell. Thus, this paper may contribute to future investigations of DSSC when choosing efficient natural dyes according to their optical and electronic properties. Therefore, this work provides the knowledge required to efficiently merge materials and dyes, in which photovoltaic energy systems’ reproducibility and scalability still represent a challenge. Lastly, this document discusses the natural pigments’ stability and the approaches to improve their chemical stability.

Peptide Materials in Dye Sensitized Solar Cells

In September 2015, the ONU approved the Global Agenda for Sustainable Development, by which all countries of the world are mobilized to adopt a set of goals to be achieved by 2030. Within these goals, the aim of having a responsible production and consumption, as well as taking climate action, made is necessary to design new eco-friendly materials. Another important UN goal is the possibility for all the countries in the world to access affordable energy. The most promising and renewable energy source is solar energy. Current solar cells use non-biodegradable substrates, which generally contribute to environmental pollution at the end of their life cycles. Therefore, the production of green and biodegradable electronic devices is a great challenge, prompted by the need to find sustainable alternatives to the current materials, particularly in the field of dye-sensitized solar cells. Within the green alternatives, biopolymers extracted from biomass, such as polysaccharides and proteins, represent the most promising materials in view of a circular economy perspective. In particular, peptides, due to their stability, good self-assembly properties, and ease of functionalization, may be good candidates for the creation of dye sensitized solar cell (DSSC) technology. This work shows an overview of the use of peptides in DSSC. Peptides, due to their unique self-assembling properties, have been used both as dyes (mimicking natural photosynthesis) and as templating materials for TiO2 morphology. We are just at the beginning of the exploitation of these promising biomolecules, and a great deal of work remains to be done.

Adamantyl Side Chains as Anti-Aggregating Moieties in Dyes for Dye-Sensitized Solar Cells.

Designing and evaluating novel dye concepts is crucial for the development of the field of dye‐sensitized solar cells (DSSCs). In our recent report, the novel concept of tethering the anti‐aggregation additive chenodeoxycholic acid (CDCA) to dyes for DSSC was introduced. Based on the performance improvements seen for this modification, the aim of this study is to see if a simplified anti‐aggregation unit could achieve similar results. The following study reports the synthesis and photovoltaic characterization of two novel dyes decorated with the steric ethyladamantyl moiety on the π‐spacer, and on the triarylamine donor. This modification is demonstrated to be successful in increasing the photovoltages in devices employing copper‐based electrolytes compared to the non‐modified reference dye. The best photovoltaic performance is achieved by a device prepared with the adamantyl decorated donor dye and CDCA, this device achieves a power conversion efficiency of 6.1 % (Short‐circuit current=8.3 mA cm−2, Open‐circuit voltage=1054 mV, Fill factor=0.69). The improved photovoltaic performance seen for the adamantyl decorated donor demonstrate the potential of ethyladamantyl side chains as a tool to ensure surface protection of TiO2.

Synthesis of Different Sizes TiO2 and Photovoltaic Performance in Dye-Sensitized Solar Cells

For more than 2 decades, extensive research has been done in the field of Dye-Sensitized Solar Cells (DSSCs) due to their low cost, easy preparation methodology, less toxicity, and ease of production. In this work, the performance of DSSCs containing different particle sizes is studied. N2-doped TiO2was prepared by the sol-gel method, controlling the particle size through the addition of different H2O/Ti mole ratios R = 0, 20, 30, and 40. The dried samples at 100°C were characterized by X-ray diffraction, Optical Properties, High-Resolution Transmission Electron Microscope, Scanning Electron Microscope, Fourier-Transform Infrared Spectroscopy, N2-Adsorption-Desorption Isotherm, Raman Spectroscopy, and Dynamic Light Scattering (DLS). DLS results show that the size of TiO2decreases as the H2O/TiO2content increases from 0 to 40. It is found that TiO2nanoparticles with smaller particle size distribution has the lowest conversion efficiency of 0.95% with H2O/Ti ratio = 40, and the photoelectrode with higher size has a conversion efficiency of 1.59% for the water-free sample. This could be explained as the larger particles have better dye adsorption, indicating that it has an effective surface area for greater photon absorption and electron-hole generation. The results also indicate that trimodal distribution with larger size also absorbs different wavelengths due to the broad distribution of the particle size.

Design of sensitizer with suitable frontier molecular orbital via substitution on starburst triphenylamine derivative.

Herein, a series of organic molecules were designed through locating different substituents on the compound (WD8-c-1) to develop their performances used as the sensitizers in the field of dye-sensitized solar cells. The geometry and relevant electronic properties of WD8-c-1 and its derivatives were simulated at the B3LYP/6-31G(d,p) level. The absorption spectra were calculated using the TD-PBE0/6-31+G(d,p) method. These calculated results show that the type and position of the substituents strongly affected the distributions of frontier molecular orbitals and the energy gaps for the WD8-c-1-derived molecules. The reorganization energies results reveal that their hole charge transfer rates are higher than that of the representative hole transport material. Moreover, the mobility of the representative WD8-c-1 derivative also has been simulated. The starburst triphenylamine with suitable substituent has the more suitable FMO energy to match those of TiO2, broad absorption region, smaller reorganization energies, and high hole mobility.

Optical-electronic performance and mechanism investigation of dihydroindolocarbazole-based organic dyes for DSSCs

In recent years, organic dye molecules as photosensitizers have played a significant role in the field of dye-sensitized solar cells. In this context, two primary dihydroindolocarbazole-based organic dyes (sk201 and sk202), which were synthesized recently by Song et al., and three further designed dyes (DMZ1-3) were theoretically investigated based on density functional theory and time-dependent density functional theory. Molecular geometries, absorption spectra, charge transfer, molecular electrostatic potential and nonlinear optical properties were quantificationally studied and visually presented to reveal the relationships between the molecular structures and performances of dyes. The effects of joining the isolated dyes and TiO2 on the molecular absorption spectra and energy levels were analyzed. Moreover, several parameters, such as efficiency of light-harvesting, driving forces of electron regeneration and injection, excited-state lifetime and vertical dipole moment, were calculated to give the multi-angle demonstrations of the photovoltaic performances for these dyes.

Efficient green synthesis of antioxidant azacoumarin dye bearing spiro-pyrrolidine for enhancing electro-optical properties of perovskite solar cells

The challenge of increasing solar cell production in our life face with respect to the quality, efficiency, and environmental (eco-friendly) demand continuous improvement in solar cell study. Solar cells have emerged as powerful techniques for satisfying the increasing energy demand. One of the successful attitudes adopted in this field is using perovskite materials, which provide a cheap approach to be widely used in fabricating solar cells. For this reason, we focus in our work on enhancing the quality of perovskite materials in order to increase its efficiency towards light absorption and increase its photovoltaic behavior. Herein, different azacoumarin additives were prepared using a series of Spiro-indolone moieties and their structures were confirmed using Fourier transform infrared (FT-IR) spectroscopy and proton nuclear magnetic resonance (1H-NMR). The prepared compounds have been subjected to quantum chemical calculations to investigate the molecular orbital parameters and to study their quantitative structure–activity and structure–property relationships. The obtained results have indicated that these compounds are promising in the field of dye-sensitized solar cells. More interestingly, these compounds have proven to be effective as antioxidants for lubricating oils. All these claims have been confirmed by experimental evidences.

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.

New D–D′–A Configured Dye for Efficient Dye-Sensitized Solar Cells

D−π–A, D–A−π–A, and other configuration-based organic dyes have shown great potential in the field of dye-sensitized solar cells (DSCs). Compared with traditional configurations, D–D′–A offers several advantages such as enrichment of the electron-donating ability, absorption spectral region, and molar extinction coefficient and inhibits dye aggregation. Hence, in this work, a novel D–D′–A-type dye has been designed and synthesized for DSC applications. In this configuration, substituted imidazole has been used as a primary donor, phenothiazine as an auxiliary donor, and cyanoacetic acid as an acceptor/anchoring group. Structural characterizations of a D–D′–A-type dye were done by using NMR and electron ionization–mass spectrometry. Photophysical, electrochemical, and computational studies were systematically performed to evaluate its electronic transitions, light-harvesting property, highest occupied molecular orbital (HOMO)/lowest unoccupied molecular orbital (LUMO) levels, and redox behavior. The photop...

Lead free, air stable perovskite derivative Cs2SnI6 as HTM in DSSCs employing TiO2 nanotubes as photoanode

Cs2SnI6 is an air-stable and non-toxic perovskite variant photovoltaic material which exhibits p-type conductivity under doped conditions. In this work, we report the synthesis and stability studies of Cs2SnI6 towards its application as a solid-state Hole Transport Material (HTM) in Titania Nanotube (TNT) based Dye Sensitized Solar Cells (DSSCs). Cs2SnI6 crystals were synthesized using precipitation method and its stability was assessed using X-ray diffraction (XRD), X-ray Photoelectron Spectroscopy (XPS) and Thermogravimetric Analysis (TGA). Cs2SnI6 doped with SnI2 was deposited onto the TNT photo-anode as the HTM layer through dip coating. Deposition time was varied to obtain a continuous layer of Cs2SnI6 HTM over TNT photo-anode and cell characteristics were studied. We were able to fabricate air stable, all solid-state solar cells with a Jsc of 6 mA/cm2, Voc of 536 mV and PCE of 1.3%. The study propounds contemporary analysis on Sn based perovskite systems, in the field of DSSCs.

First Evidence of Electrode Reconstruction in Mesoporous NiO After Operation as Photocathode of Dye‐Sensitized Solar Cells

AbstractFor the first time it is shown that the NiO films operating as photocathodes in dye‐sensitized solar cells (DSCs), alter their X‐ray diffraction (XRD) pattern upon occurrence of the photoelectrochemical reaction of reduction. In particular, it has been observed that mesoporous NiO sensitized with Fast Green (FG) presents splitting and broadening of its characteristic XRD peaks after device operation in p‐type DSC (p‐DSC) and tandem DSC (t‐DSC). The nature of the changes in the diffraction pattern of NiO does not vary with the magnitude of the current passing through the p‐DSC and the t‐DSC with NiO photocathodes. Such a combination of facts would indicate that the photoelectrochemical process of holes photoinjection mediated by the sensitizer is responsible of the structural variations in NiO photocathode. At a microscopic level, we attributed such modifications to the reconstruction of the NiO electrode following the realization of the dye‐mediated process of electron transfer with lattice deformation possibly due to the inclusion of the chemisorbed sensitizer in the oxide structure. This observation opens up a completely new direction of research in the field of DSC and analogous devices as far as the analysis and the understanding of the interactions dye/semiconductor in the common operative conditions of a DSC are concerned.

The role of metals and dithiolate ligands on structural, electronic and optical properties of [M(bipyridine)(dithiolate)] complexes: A theoretical study

A series of [M(diimine)(dithiolate)] complexes of general formula [M(bpy)(dithiolate)] {bpy=2,2′-bipyridine;dithiolate=1,2-benzenedithiolate (bdt2−), 3,4-toluenedithiolate (tdt2−) and 4-cyanobenzene-1,2-dithiolate (cbdt2−); M=Ni(II), Pd(II) and Pt(II)} have been studied by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. The geometries, stabilities, electronic structures, optical absorption spectra in different phases as well as thermodynamic parameters are explored. The changes of metal ion center and dithiolate ligands on some molecular properties are also discussed. These calculated results are in good agreement with the experimental data. The bonding analyses show that the MS bond is covalent so that always polarized towards sulfur atom, whereas the MN bond exhibits a considerable amount of electrostatic interaction. Detailed NBO analysis indicates that these complexes can be easily oxidized than reduced, and acts as the reducing agent. The HOMO-LUMO energy gaps of all complexes under study are founded about 2eV and the strong absorption from 400 to 700nm which match with the solar spectra very well. Besides, the simulated absorption spectra are in accordance with the trends of energy gaps. Comparison of the absorption spectra in dichloromethane solution with those in gas phase show that the solvatochromic effect. The order of magnitude for light harvesting efficiencies (LHE) of all complexes is Pt>Pd>Ni and cbdt2−>bdt2−>tdt2−. Our results confirm the effect and role of metals and dithiolate ligands on enhancing the optical properties of these complexes. Thus, the result of this work can serve as a rational tool for the design and synthesis of diimine-dithiolate complexes and broadens the scope for further investigations into potential dyes for use in the field of dye-sensitized solar cells (DSSC).

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.

Economically synthesized NiCo2S4/reduced graphene oxide composite as efficient counter electrode in dye-sensitized solar cell

Exploiting efficient Pt-free counter-electrode materials with low cost and highly catalytic property is a hot topic in the field of Dye-sensitized solar cells (DSCs). Here, NiCo2S4/reduced graphene oxide (RGO) was prepared via an economical synthesis route, and the as-prepared composite exhibited comparable electrocatalytic property with the conventional Pt electrode as the counter-electrode. Notably, the introduction of RGO into the NiCo2S4 counter-electrode induces a significantly promoted electrocatalytic rate towards the triiodide reduction than that of pristine NiCo2S4 by increasing surface area in the composite electrode, as revealed by electrochemical impedance spectroscopic measurement and Tafel polarization measurement. The easy synthesis, low cost and excellent electrochemical performance of the NiCo2S4/RGO composites enable themselves to serve as promising counter-electrode candidates for efficient DSCs.

Design and synthesis of organic sensitizers with enhanced anchoring stability in dye-sensitized solar cells

Abstract D-π-A dyes have received a special attention in the field of dye-sensitized solar cells (DSSCs). In this kind of molecules, the acceptor group (A) generally acts as an anchor, enabling the adsorption of the dye onto the metal oxide substrate (TiO2) and providing a good electron injection. The search for new anchors represents a critical factor for the development of improved DSSCs and in recent years has been a very active research field. This mini-review focuses especially on our work on pyridine-derived anchoring groups for D-π-A dyes, with a special regard on the preparation and characterization of three different families of dyes and a critical evaluation of their stability and efficiency.

Effect of Nanodiamonds on the Optoelectronic Properties of TiO $$_{2 }$$ 2 Photoanode in Dye-Sensitized Solar Cell

Low charge transfer resistance and high light absorption ability of TiO $$_{2}$$ -based photoanodes are the crucial challenges in the field of dye-sensitized solar cells (DSSCs). In this study, nanodiamonds (NDs) have been introduced in TiO $$_{2}$$ matrix to investigate their effect on the performance of DSSCs. Colloidal suspension method has been employed for the synthesis of TiO $$_{2}$$ /NDs nanocomposites. Various concentrations of NDs, i.e., TiO $$_{2}$$ –0.2 wt%NDs, TiO $$_{2}$$ –0.5 wt%NDs, TiO $$_{2}$$ –1 wt%NDs, TiO $$_{2}$$ –3 wt%NDs and TiO $$_{2}$$ –5 wt%NDs, have been trialed for the fabrication of nanocomposite photoanode using doctor blade method with D719 dye as sensitizer. Scanning electron microscopy and X-ray diffraction methods were used to study the morphology, composition and dispersion of NDs in TiO $$_{2}$$ matrix. UV–visible absorption spectroscopy, photocurrent–voltage characteristics and electrochemical impedance spectroscopic measurements were conducted to characterize the performance of DSSCs. The results show that the photoconversion efficiency is highly dependent on the concentration of NDs in the photoanode due to high light absorption, dye loading and heterojunction symmetry of the system. A solar cell based on a photoanode containing 3 wt% NDs showed a power conversion efficiency of 0.47% compared to 0.26% efficiency of unmodified photoanode.

The revival of dye-sensitized solar cells

The scientific progress in the field of dye-sensitized solar cells (DSCs) is marked by a recent number of important breakthroughs. DSCs provide a technically and economically credible alternative concept to present-day p–n junction photovoltaic devices. Relentless efforts helped to achieve high efficiencies with DSCs. Some of the major progress was made by developing new panchromatic rigid structure dye systems, new redox shuttles and hole transport materials. Under full sun illumination (standard AM 1.5 G), conversion efficiencies have reached over 13% with Zn porphyrins and 14% with co-sensitized organic dyes. The new redox couples and electrolytes are able to regenerate the dye at less than 0.2 V. Current research and development is the perquisite to improve efficiencies beyond 20% for future applications with improved stability and sustainability.