Dyes For Dye-sensitized Solar Cells Research Articles

Theoretical analysis on D-π-A triphenylamine-based dyes for dye-sensitized solar cells: effect of π-bridges on the optoelectronic, and photovoltaic properties.

The dye-sensitized solar cell is a technology unique in its light conversion properties as it operates with record efficiencies in diffused light conditions. The choice of the appropriate sensitizer is one of the important strategies to improve photovoltaic performance of DSSC devices. This theoretical study mainly aims to determine the impact of the π-spacer on the geometric and optoelectronic parameters of sensitizer dyes. For that, we have chosen six organic dyes of Donor-π-Acceptor structure based on triphenylamine unit as electron donor, cyanoacrylic acid as electron acceptor with various π-bridges. The results indicated that the doping process modify dihedral angles and electronic properties by enhancing the planarity and decreasing the gap energy. We have examined the optoelectronic and photovoltaic properties of studied triphenylamine based-dyes. Introducing thiophene and furan as π-spacer groups in D6 dye can effectively decrease the gap energy (Egap = 2.21 eV), broaden the absorption range (λmax = 671.19 nm), and promote the light-harvesting properties. The D2 dye based on two pyrrole units presents an improved electron injection driving force (ΔGinject = - 2.269 eV) and regeneration driving force corresponding to better charge separation. The π-bridge groups can efficiently tune the optoelectronic and photovoltaic properties of sensitizers, which contribute to the efficiency of solar cells. The geometrical and electronic properties of all systems were studied by the DFT method using the correlation exchange functional B3LYP combined with 6-31G(d, p) basis set. On the other hand, the maximum absorption wavelengths λmax and the corresponding oscillator strengths were calculated using the hybrid functional BHandHLYP and 6-31+G(d) basis set. The solvent tetrahydrofuran (THF) are used to study the effect of the solvent, using the "Conductor-Polarizable Continuum" (C-PCM) model. All calculations were performed using Gaussian 09 program.

Exploring the impact of structural rigidification of amino-substituted bio-inspired flavylium dyes in DSSCs

Sharing with anthocyanins the 2-phenyl-1-benzopyrylium structural motif, flavylium derivatives are strongly colored bio-inspired dyes that have been explored in dye-sensitized solar cells (DSSCs). Following on the fact that the most efficient flavylium-based dyes for DSSCs require amine electron-donating groups, a diethylamino group and the corresponding rigidified julolidine group were introduced in the benzopyrylium core. This structural variation was combined with another structural parameter – increased planarization of the flavylium ring system – to yield four flavylium derivatives all with a catechol anchoring group. The several pKa values of the new dyes and the UV–vis absorption data at different pH values and upon adsorption to TiO2 (corroborated by TD-DFT calculations) demonstrate a stronger delocalization of the nitrogen lone pair in the julolidine systems when compared to the diethylamino ones, reflecting the stronger electron-donating ability of the former. However, the julolidine-based dyes resulted in a decrease in all DSSC parameters, with efficiencies of 0.6% vs. 2.3% for the diethylamino devices. Discarding eventual increased self-aggregation processes of the more planar julolidine derivatives through studies with a de-aggregating agent (CDCA), and determining comparable dye loadings for all dyes, the presence of increased back-electron transfer processes for the julolidine-based compounds is advanced to explain their lower efficiencies. Rigidification of the flavylium dyes by bridging the benzopyrylium and the phenyl rings is demonstrated by higher fluorescence quantum yields and by electrochemical data and leads to a slight increase in the efficiency of the respective DSSCs. The results contribute to consolidate the potential of flavylium dyes as sensitizers for DSSCs.

Influence of spacer and donor groups as tetraphenylethylene or triphenylamine in asymmetric zinc phthalocyanine dyes for dye-sensitized solar cells

Based on the available literature, the carboxylic acid is a suitable electron-withdrawing group for the development of push–pull type AB3 phthalocyanines that can be used in dye-sensitized solar cell (DSSC). This study aims to assess the impact of carboxylic acid groups on solar cell energy conversion efficiency. Two types of carboxylic acid groups were selected as electron-withdrawing groups for this purpose. These groups were attached to the phthalocyanine (Pc) core either directly or via conjugated linker groups. Two novel push–pull zinc phthalocyanine dyes (GT-52 and GGC-22) containing tetraphenylethylene (TPE) or triphenylamine (TPA) substituents as electron donor groups and carboxylic acid or phenoxy carboxylic acid as anchoring groups, respectively, have been synthesized to construct DSSCs. The optical, electrochemical, and photovoltaic properties of the effect of the spacer and electron donor groups in these phthalocyanines are evaluated. Both dyes exhibit good anti-aggregation ability owing to the presence of the bulky donor groups. On the other hand, the DSSC based on GGC-22 showed a significantly higher power conversion efficiency (PCE) of 2.15% than that of GT-52 (0.26%) under AM 1.5G solar conditions. The superior performance of GGC-22 is attributed to the introduction of a phenoxy spacer, which results in a longer distance between the donor groups and the TiO2 surface compared to GT-52 without any spacer. This allows for higher dye loading, resulting in higher JSC, VOC, and PCE for GGC-22. As a result, the presence of a longer anchoring group for the donor groups is an important synthetic strategy for efficient phthalocyanine-based DSSCs.

Hydrazonothiazole dyes for enhanced dye-sensitized solar cells in greenhouse applications: Achieving high power conversion efficiency and long-term stability

Dye-sensitized solar cells (DSSCs) offer a cost-effective and attractive alternative to traditional solar cells for greenhouse applications. Hydrazonothiazole dyes (MHS-1-4) have been investigated as a viable DSSC technology, with researchers designing dyes that absorb light in the green region, while transmitting light in the red and blue regions, making them the ideal fit for plant growth. Sensitized devices display impressive power conversion efficiency (PCEs) ranging from 6.27 to 8.85%, with MHS-4 DSSCs achieving an 8.85% power conversion efficiency, a short-circuit photocurrent density of 17.90 mA cm−2, and a maximum incident monochromatic photon-to-electron conversion efficiency (IPCE) of 80%. Furthermore, DSSCs based on MHS-4 demonstrate excellent long-term stability, sustaining nearly constant power conversion efficiency after exposure to one-sun illumination for 1000 h. This breakthrough study demonstrates the potential for hydrazonothiazole dyes in DSSCs, marking a significant step forward in the development of cost-effective solar cell technology compatible with plant growth. With MHS-1-4 dyes' ability to effectively convert photoelectric energy throughout the visible range, and even into the near-infrared (NIR) region up to 900 nm, they offer a new benchmark for DSSC technology.

Design of a D–Di–π–A Architecture with Different Auxiliary Donors for Dye‐Sensitized Solar Cells: Density Functional Theory/Time‐Dependent‐Density Functional Theory Study of the Effect of Secondary Donors

AbstractIn this work, five novel D–Di–π–A molecules based on ethoxy donor moiety are designed from the reference molecule R to optimize the photovoltaic performance of dye‐sensitized solar cell (DSSC) systems. The geometrical, electronic, optical, and photovoltaic characteristics of the D1–D5 compounds are analyzed. D1–D5 show band gaps (Egap) in the range of 2.13–2.25 eV with the maximum absorption wavelength (λabs) in 427–451 nm. Charge transport characteristics are examined by employing frontier molecular orbitals and density of states. The transition density matrix is employed to predict the characteristics of the electronic excitation mechanisms and the localization of the electronic holes betwixt the donor and acceptor moieties. The data obtained indicate that adding the various auxiliary donors to dye (R) facilitate its electron injection and improve the impact of intramolecular charge‐transfer (ICT), which lead to a red‐shifted absorption. The open‐circuit voltage (Voc) data obtained from theoretical computations vary from 1.26 to 1.30 eV, while the data for the light harvesting efficiency range from 0.97 to 1.00. Indeed, this study may help chemists to synthesize efficient dyes for DSSC.

Blueberries as a Source of Energy: Physical Chemistry Characterization of Their Anthocyanins as Dye-Sensitized Solar Cells’ Sensitizers

This work aimed to show the possibility of applying anthocyanins extracted from blueberries following a straightforward path as potential impregnation dyes in dye-sensitized solar cells (DSSCs), particularly in the presence of co-adsorbents, such as silver nanoparticles, as an alternative in order to profit from large amounts of discarded fruits. Following a simple procedure, anthocyanins (mainly delphinidin-3-glucoside) were obtained from blueberries (Southern Highbush type). Complete characterization was carried out in order to prove the utility of delphinidin-3-glucoside as a sensitizer in DSSCs. The analyzed anthocyanin is suitable for sensitizing because of its high molar absorptivity values within the visible region of the light spectra, the adsorption ability to a FTO/TiO2 electrode (FTO, fluorine-doped tin oxide) as confirmed by Fourier transform infrared (FTIR) as well as thermogravimetry coupled to differential scanning calorimetry (TG-DSC), a potential oxidation value near 1 V, and adequate thermal as well as light stabilities. Moreover, the cell’s conversion efficiency is improved in the presence of silver nanoparticles, reaching 0.24% (nearly a 25% increase). The sum of all these characteristics points to the application of delphinidin-3-glucoside as a sensitizer in DSSCs, offering a technological use with potential interest for countries where agricultural production offers an abundant origin of extraction.

The impact of aromatic π-spacers and internal acceptors in triphenylamine dyes for DSSCs: A DFT approach

In present work, the influence of internal acceptors and π-spacers on optoelectronic properties for dye-sensitized solar cells (DSSCs) is investigated. The dyes consist of various internal acceptors (A), a triphenylamine donor and π-spacers combined with cyanoacrylic acid acceptor. Density functional theory (DFT) was employed to inspect the dye geometries, charge transport characteristics and electronic excitations. The frontier molecular orbitals (FMOs), highest occupied molecular orbital, lowest unoccupied molecular orbital and HOMO-LUMO energy gap are assisted in the determination of suitable energy levels for electron transfer, electron injection and regeneration of dye. The required photovoltaic parameters like JSC, ΔGreg, ΔGinj, LHE and other associated parameters are presented. The results demonstrate that altering the π-bridge and adding an internal acceptor to the D-π-A scaffold changes the photovoltaic properties and absorption energies. Therefore, the key objective of the current effort is to launch a theoretical groundwork for suitable operational alterations and scheme in creating successful DSSCs.

Theoretical calculation of the influence of internal acceptor on photovoltaic performances in triphenylamine-based dyes for dye-sensitized solar cells

Novel series of D-A2-π-A1 metal-free organic dyes are taken into consideration to investigate the influence of different internal acceptors on their efficiency in dye sensitized solar cells (DSSCs), these dyes are designed based on C218 reference dye. The crucial parameters affecting open circuit photovoltage (VOC) and short circuit current density (JSC), as well as light harvesting efficiency (LHE), driving force of regeneration (ΔGreg), electronic injection driving force (ΔGinj), vertical dipole moment (μnorm), electron reorganization energy (λe), hole reorganization energy (λh), ionization potential (IP), electron affinity (EA), chemical hardness (h), electrophilicity (ω), electroaccepting power (ω+), and the conduction band shift (ΔECB) are theoretically investigated in detail using density functional theory (DFT) and time dependent density functional theory (TD-DFT) methods. The results indicate that the insertion of internal acceptor between donor and π-bridge moieties leads to red-shifted for the UV–vis absorption spectra and improves the photovoltaic properties. Thus, this study is expected to provide a theoretical basis for proper design and structural modifications in the development of dyes in dye-sensitized solar cells (DSSCs).

Double Fence Porphyrins Featuring Indacenodithiophene Group as an Effective Donor for High‐Efficiency Dye‐Sensitized Solar Cells (Adv. Energy Mater. 20/2023)

Dye-Sensitized Solar Cells In article number 2300353, Tzu-Chien Wei, Chen-Yu Yeh, and co-workers report new porphyrin dyes for dye-sensitized solar cells. The indacenodithiophene unit is used for improving the light-harvesting ability of dyes, and appropriate alkoxyl chains are chosen to balance dye loading amount and molecular aggregation, and retard the approach of the electrolyte to the surface of TiO2.

Molecular Photoinduced Charge Separation: Fundamentals and Application

Abstract We have designed and synthesized a number of donor-acceptor linked systems to elucidate the science of photoinduced charge separation. In particular, porphyrin-fullerene and polymer-fullerene linked molecules have been found to be very useful as model systems for addressing issues in excited-state generation, charge separation, and charge dissociation. We have also proposed a new concept, “dynamic exciton” to establish new comprehensive photochemistry dealing with manipulation of locally excited state, charge-transfer state, and charge-separated state involving mutual transformation. Simultaneously, it is pivotal to adopt time-dependent dynamic effects on electron and spin behaviors entangled with movement of atomic nuclei (i.e., vibration, rotation, and fluctuation) and their collective motion into molecular donor-acceptor systems. Versatile dyes for dye-sensitized solar cells as well as donor/acceptor molecules for bulk heterojunction organic solar cells have also been tailored toward better understanding the underlying mechanism as well as improving their photovoltaic performances. Meanwhile, giant dipole moment produced from donor-acceptor linked molecules by light has been successfully utilized to regulate the membrane potential of living biological cells. This is the first example of the use of charge-separated state in optogenetics and is promising as neuronal therapy by light.

Synthesis and characterization of cobalt (II) pincer complexes and their application as dyes in dye-sensitized solar cells

A series of eight cobalt(II) pincer complexes were prepared by using NNN tridentate and NN bidentate pincer ligand systems. All the ligands and complexes were completely characterized using various spectroscopic techniques and analytical methods including single crystal X-ray analysis. Optimization of the molecular structures of all the compounds was done by B3LYP computational method and the HOMO-LUMO energy gaps of the compounds were calculated. The optical band-gaps of the cobalt complexes were determined by using electronic spectral data and the corresponding electrochemical gaps were obtained from cyclic voltammetry studies. All the cobalt (II) complexes were used as dyes in the dye-sensitized solar cell and the photovoltaic parameters of the constructed solar cells were investigated. Complex C7, comprising of bis(benzimidazole) system with an ethylene backbone exhibited highest power conversion efficiency among the tested compounds.

Double Fence Porphyrins Featuring Indacenodithiophene Group as an Effective Donor for High‐Efficiency Dye‐Sensitized Solar Cells

AbstractPorphyrins are an important category of dyes for efficient dye‐sensitized solar cells (DSSCs). However, the efficiency improvement of DSSCs lags behind those of organic and perovskite solar cells owing to deficiencies in new design strategies of dye molecular structures. Recently, double fence porphyrins with superior photovoltaic performance were reported, in which eight alkoxyl chains were introduced to wrap the porphyrin core and retard the approach of the electrolyte to the surface of TiO2. On the basis of the design strategy of double fence porphyrins, novel porphyrins bJS8, YS2, YS3, YS7, and MC1 featuring dual functional indacenodithiophene group are synthesized and their photovoltaic performance in DSSCs are studied. Among these new double fence porphyrin dyes, YS7 exhibits an improved power conversion efficiency of 11.4% (short circuit photocurrent (JSC) = 17.34 mA cm−2, open circuit photovoltage (VOC) = 0.864 V, and fill factor (FF) = 0.758) compared to the previously reported double fence porphyrin bJS2 of 10.7% (JSC = 16.59 mA cm−2, VOC = 0.849 V, and FF = 0.759) and the benchmark porphyrin dye GY50 of 10.1% (JSC = 16.14 mA cm−2, VOC = 0.863 V, and FF = 0.725) under optimized conditions, providing a new molecular design strategy for high‐efficiency porphyrin dyes in DSSCs.

Application of Covalent Organic Frameworks (COFs) as Dyes and Additives for Dye-Sensitized Solar Cells (DSSCs).

Five Covalent Organic Frameworks (COFs) were synthesized and applied to Dye-Sensitized Solar Cells (DSSCs) as dyes and additives. These porous nanomaterials are based on cheap, abundant commercially available ionic dyes (thionin acetate RIO-43, Bismarck brown Y RIO-55 and pararosaniline hydrochloride RIO-70), and antibiotics (dapsone RIO-60) are used as building blocks. The reticular innovative organic framework RIO-60 is the most promising dye for DSSCs. It possesses a short-circuit current density (Jsc) of 1.00 mA/cm2, an open-circuit voltage (Voc) of 329 mV, a fill factor (FF) of 0.59, and a cell efficiency (η) of 0.19%. These values are higher than those previously reported for COFs in similar devices. This first approach using the RIO family provides a good perspective on its application in DSSCs as a dye or photoanode dye enhancer, helping to increase the cell's lifespan.

Novel pyridoquinazolindone-containing triphenylamine dyes for dye-sensitized solar cells

Four novel “A-D-π-A” pyridoquinazolinone-containing triphenylamine dyes were synthesized for dye-sensitized solar cell (DSSCs), which consist of triphenylamine as the electron donor, thiophene or CC bond as π-bridge, cyanoacrylic acid as the electron acceptor and pyridoquinazolinone as the auxiliary acceptor. Their photophysical, electrochemical properties and photovoltaic performance were investigated. Moreover, density functional theory (DFT) was performed for theoretical calculations. The results show that the incorporation of additional pyridoquinazolinone unit enables dyes with larger charge recombination resistance than the dyes with single pyridoquinazolinone unit, which benefits the increase of Voc. Besides, the introduction of thiophene bridge can broaden and red-shift the absorption region, which endows the dyes with better light-harvesting ability and subsequently brings about superior IPCE and Jsc. Therefore, dye with double pyridoquinazolinone units and thiophene bridge exhibits the best photoelectric conversion efficiency 5.19 % (Jsc = 11.71 mAcm−2, Voc = 0.67 V, ff = 0.70).

Potential Dye Suji Leaves (Pleomele angustifolia) Chlorophyll and Red Dragon Fruit Peel (Hylocereus polyrhizus) Anthocyanins as Natural Dyes for Dye-Sensitized Solar Cells

In this study, the quality analysis of chlorophyll and anthocyanin extraction dyes from suji (Pleomele angustifolia) leaves and red dragon fruit (Hylocereus polyrhizus) peel was extracted using ethanol as a natural dye for dye-sensitized solar cells (DSSCs). Dye characterization was carried out using UV-visible spectrophotometry to determine the wavelength absorption and bandgap using the Tauc plot method, electrochemical characterization of dye was carried out using cyclic voltammetry. The efficiency of DSSC was measured using a digital multimeter. In this study, chlorophyll was produced with absorption wavelengths at 663 nm and 439 nm while anthocyanin dye was at a wavelength of 532 nm. The bandgap of chlorophyll was calculated to be 2.51 eV and that of anthocyanins to be 2.1 eV using the Tauc plot method.. The electrochemical results shows that chlorophyll dye of suji leaves has HOMO energy (highest occupied molecular orbital) at -5.68 eV and a LUMO energy (lowest unoccupied molecular orbital) at -3.17 eV while anthocyanin has HOMO energy of -5.16 eV and a LUMO energy of -3.06 eV. The efficiency produced by DSSC with chlorophyll dye was 3.4163 × 10-3 % and anthocyanins were 6.3994 × 10-3 %. These results show that chlorophyll and anthocyanin dyes from suji leaves and red dragon fruit peel are promising reagents to be used as DSSC dyes.

Design, synthesis and functionalization of BODIPY dyes: applications in dye-sensitized solar cells (DSSCs) and photodynamic therapy (PDT)

The present review focuses on the design, synthesis, functionalization, and application of BODIPY dyes in dye-sensitized solar cells and photodynamic therapy.

Halogen functionalized D–A–D-type unsymmetrical squaraine dyes for dye-sensitized solar cells

A series of alkyl-group-wrapped and halogen atom functionalized unsymmetrical squaraine dyes (ISQ) were designed and synthesized. A maximum DSSC device efficiency of 7.80% was achieved for iodine funtionalized ISQ-I dye in Z-150 with CDCA.

Machine learning-based q-RASPR modeling of power conversion efficiency of organic dyes in dye-sensitized solar cells

The novel quantitative read-across structure–property relationship approach was used to model the power conversion efficiency of four classes of organic dyes.

Energy level tuning of push-pull porphyrin sensitizer by trifluoromethyl group for dye-sensitized solar cells

We have introduced trifluoromethyl groups into meta-positions of two meso-phenyl rings of a push-pull-type porphyrin dye (ZnP-CF[Formula: see text] to modulate the energy levels of the porphyrin dye for dye-sensitized solar cells (DSSCs). The light-harvesting ability of ZnP-CF[Formula: see text] is almost comparable to those of reference porphyrins where the trifluoromethyl groups are replaced with methyl (ZnP-CH[Formula: see text] or tert-butyl groups (YD2). We revealed that the introduction of the electron-withdrawing trifluoromethyl groups is effective to lower the excited-state oxidation potential of the porphyrin (–0.80 V vs NHE), which is consistent with the theoretical calculation. Meanwhile, DSSCs with ZnP-CF[Formula: see text] exhibited a lower power conversion efficiency ([Formula: see text] of 5.95% than DSSCs with ZnP-CH[Formula: see text] ([Formula: see text] = 7.33%) and YD2 ([Formula: see text] = 8.97%) because of the severe aggregation tendency of ZnP-CF[Formula: see text] arising from the trifluoromethyl groups. In addition, the insufficient steric bulkiness of the trifluoromethyl and methyl groups relative to tert-butyl groups would result in the lower short circuit current and open circuit voltage for ZnP-CF[Formula: see text] and ZnP-CH[Formula: see text] due to fast charge recombination between electrons in the conduction band of TiO2 and I[Formula: see text]in the electrolyte solution. Overall, introducing both trifluoromethyl groups and bulky substituents into a porphyrin core would be necessary to boost cell performance.

Enhancement of Power Conversion Efficiency with Zinc Oxide as Photoanode and Cyanococcus, Punica granatum L., and Vitis vinifera as Natural Fruit Dyes for Dye-Sensitized Solar Cells

Ruthenium N719 is a well-known material used as the dye in commercial dye-sensitized solar cell (DSSC) devices. However, it poses risks to human health and the environment over time. On the other hand, titanium dioxide (TiO2) has low electron mobility and high recombination losses when used as a photoanode in this photovoltaic technology device. In addition, using Ruthenium as the dye material harms the environment and human health. As an alternative sensitizer to compensate Ruthenium on two different photoanodes (TiO2 and ZnO), we constructed DSSC devices in this study using three different natural dyes (blueberry, pomegranate, and black grape). In good agreement with the anthocyanin content in the fruits, black grape, with the highest anthocyanin content (450.3 mg/L) compared to other fruit dyes (blueberry—386.6 mg/L and pomegranate—450.3 mg/L), resulted in the highest energy conversion efficiency (3.63%) for the natural dye-based DSSC. Furthermore, this research proved that the electrical performance of natural dye sensitizer in DSSC applications with a ZnO photoanode is better than using hazardous Ru N719 dye with a TiO2 photoanode owing to the advantage of high electron mobility in ZnO.