Dyes For Solar Cells Research Articles

Investigation of the impact of internal acceptor and π-linker in 2, 5-di(2-thienyl)pyrrole based organic dye photosensitizer for DSSCs

The effect of π-linkers and internal acceptor group on the optoelectronic characteristics of D-π-A and D-A′-π-A dyes for dye-sensitized solar cells (DSSCs) were examined. The DFT was used for estimating geometries and charge transport parameters, and the TD-DFT for calculating electronic excitations of these dyes. HOMO, LUMO, and HOMO-LUMO energy gap were also calculated for appreciating the suitable electron transfer, dye regeneration, and charge injection. For achieving the improved performance of dyes in DSSC, injection driving force (ΔGinj), short circuit current density (JSC), the open circuit voltage (VOC), light harvesting efficiency (LHE), dye regeneration energy (ΔGreg), and Power conversion efficiency were also determined. For suitable Power conversion efficiency of the DSSCs, electron affinity (EA), hole and electron extraction potential, Ionization potential (IP), Total density of states, and Electrostatic potential (ESP) were also calculated. The result shows that the internal acceptor and π-linkers affect the photovoltaic parameters and a small variations in the dye architecture increase the efficiency of DSSCs. The dyes containing biphenyl π-linkers showed maximum power conversion efficiency for solar cell.

Design and predict the potential of imidazole-based organic dyes in dye-sensitized solar cells using fingerprint machine learning and supported by a web application

This scientific paper presents a novel approach to explore and predict the potential of imidazole-based organic dyes for use in Dye-Sensitized Solar Cells (DSSCs) using a machine learning web application. The design of efficient and cost-effective organic dyes is critical to enhance the performance of DSSCs. Traditional experimental methods are time-consuming and resource-intensive, making it challenging to screen a large number of potential dyes. In this study, we propose a machine learning-based approach to accelerate the discovery process by predicting the photovoltaic performance of imidazole-based organic dyes. Machin learning predictions provide valuable insights into the expected PCE% and behaviors of the molecules toward DSSCs. Based on the RDKit library, several fingerprints such as Molecular ACCess System, Avalon, Daylight, Pharmacophore and Morgan with different radius (r2, r3, r4), were studied. In addition, more than 20 ML algorithms using different cross validation (3, 5, 7, 10) were also evaluated. Among of these, Deep Neural Network models of MLPRegressor algorithm based on the daylight fingerprint shows a significant coefficient of determination combined with the lowest errors. Utilize the trained ML models to screen of 50 million SMILE structure for identify promising imidazole and nitrogen-containing derivative as a doner group. By replacing the donor groups in the well-known MK2 dye structure with the top imidazole derivatives proposed by machine learning, significant improvements in PCE were observed, increasing from 7.70% to as high as 11.49%, representing nearly a 50% enhancement over the control. DFT calculations confirm the ML predictions and clarify the significantly higher oscillator strength and charge transfer properties of MK2-DM1, compared to MK2. This result provides a promising pathway for developing new dye materials that can push the efficiency limits of DSSCs, leading to more efficient solar energy conversion technologies in the future. In addition, a developed web application offers a user-friendly interface for researchers to input their molecular structures and obtain PCE% predictions toward DSSCs. This information can guide researchers in designing a new imidazole dye with high photovoltaic performance to validate and refine the predictions without time consuming.

Novel unsymmetrical squaraine dyes for dye-sensitized solar cells: Synthesis, characterization, and comparative photovoltaic performance of USQI-NPh2Me2 and USQI-OMe

This study presents the synthesis, characterization, and photovoltaic performance of two novel unsymmetrical squaraine dyes, USQI-NPh2Me2 and USQI-OMe, engineered for application in dye-sensitized solar cells (DSSCs). These chromophores were functionalized with distinct electron-donating groups, di-p-tolylamine for USQI-NPh2Me2 and methoxy for USQI-OMe. Their molecular structures were confirmed through FT-IR, 1HNMR, 13C NMR, and mass spectrometry. Comprehensive photophysical and electrochemical studies were conducted to fine-tune the HOMO and LUMO energy levels of both dyes, optimizing charge injection into the TiO2 conduction band and facilitating dye regeneration with the iodolyte (I₃⁻/I⁻) redox mediator. USQI-NPh2Me2 exhibited a strong absorption maximum at 661 nm, achieving a high short-circuit current density (JSC) of 13.17 mA/cm2, an open-circuit voltage (VOC) of 0.71V, and an overall efficiency of 7.01 %. USQI-OMe, with its absorption peak at 651 nm, reached a JSC of 11.88 mA/cm2, a higher VOC of 0.72 V, but a slightly lower overall efficiency of 6.41 %. Both dyes demonstrated reduced aggregation on the TiO2 surface, contributing to enhanced DSSCs performance. A Comparative analysis revealed that USQI-NPh2Me2 exhibits higher efficiency, while USQI-OMe provided a greater voltage output, highlighting the influence of electron-donating groups on photovoltaic properties. These findings provide valuable insights into structure-property relationships in unsymmetrical squaraine dyes, paving the way for future DSSCs chromophore design and optimization.

Investigation of heterocyclic azo dyes for dye-sensitized solar cells and non-linear optical properties: Synthesis and in-silico studies

Four thiophene-based donor-π-azo-acceptor dyes were designed and synthesized with benzoic and salicylic acids anchoring groups for dye-sensitized solar cells (DSSC). The results show that the orientation of the secondary donor significantly affects molecular planarity, which in turn affects the characteristics of charge transfer (CT) inside the backbones of thiophene-azo-benzoic or salicylic acids. These results have been confirmed by the time-dependent density functional theory (TD-DFT) study, which shows that the dyes' vertical absorption maximum increases as the secondary donors' providing strength increases. Photovoltaic parameters indicate an increase in DSSC performance from PG9 to PG12. Moreover, dye@TiO2 cluster investigations suggest that these dyes could combine with TiO2 to cause dye@TiO2 cluster absorbance to shift red.The synthesis of PG9 to PG12 confirms theoretical predictions, with initial absorption in dimethylformamide (DMF) and energies of the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) following a pattern like that seen in density functional theory (DFT) investigations. According to TGA data, PG9 to PG12 have exceptional thermal stability, making them suitable for DSSCs. The built-in DSSCs had varying efficiencies; PG10 had the highest efficiency at 4.73 ± 0.1, and PG12 had the lowest at 1.72 ± 0.1. According to the theoretical and practical DSSC results, secondary donors are essential in defining molecular properties and device performance.

Triazatruxene Amine Donor-Based Visible-Light-Responsive Unsymmetrical Squaraine Dyes for Dye-Sensitized Solar Cells

Triazatruxene Amine Donor-Based Visible-Light-Responsive Unsymmetrical Squaraine Dyes for Dye-Sensitized Solar Cells

Theoretical exploration of a di-carbazole based dye for 3rd generation dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) are known for their large potential in green, efficient and cost-effective solar energy technology. Therefore, investigating the solar-to-electricity conversion mechanism of photosensitizers in DSSCs can open up a new way for highly effective and stable solar cell devices. In this study, we used different molecular design strategies to develop various D-π-A photosensitizers based on dicarbazole. These approaches involved changing the positions of auxiliary acceptors and π-spacers as well as introducing new π-spacer units. To calculate the physical and electronic properties of these sensitizers, density functional theory (DFT) and time dependent density functional theory (TDDFT) were adopted. FMO analysis showed a significant charge transfer from the donor through the spacer to the acceptor which was also supported by DOS analysis. Energy gap of designed dyes have less than experimental Cz dye. NBO analysis has carried out the bond strength assessment and the studied molecule’s central nitrogen atoms related MOs. All the designed dyes exhibited good nonlinear optical (NLO) properties with maximum linear polarizability 〈α〉 amplitudes higher than first (βtotal) compared to the reference chromophore. Photovoltaic efficiency has been evaluated to electronic (Egap), open circuit voltage (VOC), short circuit current density (JSC), electron injection ability (∆Ginj), electron regeneration (∆Greg) and light harvesting efficiency.

Sosialisasi Pemanfaatan Pewarna Alami Pada Sel Surya di MAS Darrul Mukarram Barito Kuala

As many as 44 students have carried out community service at MAS DaruL Mukarram with the title socialization on the use of natural dyes in solar cells. The aim of this service is to educate students to have knowledge, be creative, apply and teach in society about one of the alternative energies in the form of solar cells based on natural raw materials. As for the results of knowledge regarding this socialization, there was an increase in students' understanding, as seen by the students' average score of 92.5 during the post test

Molecular Engineering Strategies of Spectral Matching and Structure Optimization for Efficient Metal-Free Organic Dyes in Dye-Sensitized Solar Cells: A Theoretical Study.

Metal-free organic dyes are promising dyes that can be applied widely in dye-sensitized solar cells (DSSCs). The rational design and selection of dyes with complementary absorption can promote the development of methods that can enhance the utilization of incident light by DSSCs, such as cosensitization and tandem devices. Based on these opinions, the structure of the reported high-performance metal-free organic dye ZL003 is used as a template to design two new metal-free organic dyes, HX-1 and HX-2, by replacing its donor unit with a 2-phenothiazine-phenylamine unit and fusing its three independent π-bridge units into a whole with the aim of driving the red shift and the blue shift of the absorption spectra of ZL003, respectively. Through theoretical investigation, it is demonstrated that the perfect complementary optical absorption of HX-1 and HX-2 can be realized as the shift of the absorption spectra of ZL003 to different directions, which means their feasibility to the application in cosensitization or tandem dye-sensitized solar cells (T-DSSCs). Furthermore, it is hypothesized that HX-1 may be the dye with better photovoltaic performance than ZL003 by modeling their intramolecular charge-transfer (ICT) processes, TiO2 surface adsorption, and photovoltaic parameters. The short-circuit current density (Jsc) and photoelectric conversion efficiency (PCE) of HX-1 are 23.10 mA·cm-2 and 21.26% in theory, compared to those of 20.68 mA·cm-2 and 19.64% in ZL003 at the same computational level, respectively. In view of the complementary optical properties, the combination of HX-1 with HX-2 may be a reasonable option for dyes for the development of a highly efficient cosensitization system or T-DSSCs in the future. In terms of such findings, these two novel metal-free organic dyes may have bright prospects in the research of highly efficient DSSCs, and this work can provide a reference for the design of dyes with complementary absorption through simple structural adjustments of the realistic dyes with high photovoltaic performance.

Photovoltaic performance enhancement via cocktail co-sensitization of D–A–π–A and D–π–A–π–A dyes in dye-sensitized solar cells

A novel organic dye (BIM37) featured with donor–auxiliary acceptor–π–acceptor (D–A–π–A) structure based on an acridine π–bridge has been designed and synthesized for dye-sensitized solar cells (DSSCs). Unlike the acridine-based D–π–A–π–A dyes (BIM25 and BIM26), BIM37 was obtained by inserting an auxiliary acceptor between the donor and π–bridge units. This modification leads to a significant red shift in the absorption spectrum compared to its counterparts. Thus, the DSSCs based on BIM37 achieved a power conversion efficiency (PCE) of 5.03%, which is higher than that of BIM25 (3.76%) or BIM26 (4.56%). To further improve the photovoltaic performance, the cocktail co-sensitization strategy was applied. In the presence of chenodeoxycholic acid (CDCA) as a co-adsorbent, the co-sensitized DSSC based on BIM37+BIM26 showed a high efficiency of 6.30%. This performance is superior to individual DSSCs with and without CDCA. The results show that molecular engineering for co-sensitization may be an effective strategy to improve the performance of DSSCs.

Investigating the effect of nitrogen and chlorine Co–doped carbon quantum dots in phenazine and quinoxaline sensitized solar cells

We investigated five dyes for dye-sensitized solar cells (DSSCs) relying upon derivatives of phenazine and quinoxaline and also studied their optical characteristics and the influence of functional groups such as (-CH3, -NO2, -C = O, -CN, and -OH) on these characteristics. When the prepared dyes are directly used at DSSCs, 9-Nitrobenzo[a]phenazin-5-ol (3b) dye device showed an improved Jsc (0.288 mA cm−2), Voc (0.437 V), FF (0.446), and η (0.056 %) than the sensitized solar cells by other dyes. In the following, nitrogen-doped carbon quantum dot and nitrogen, chlorine co-doped carbon quantum dot are used to improve the performance of DSSCs. The results showed that the device sensitized using the sensitizer (5-hydroxybenzo[α]phenazin-9-yl)(phenyl) methanone (3c)/NCQD has the highest photovoltaic efficiency with Jsc (0.979 mA cm−2), Voc (0.465 V), FF (0.370), and η (0.168 %). The N and Cl co-doped carbon dots were synthesized with a green approach to improve the performance of solar cells by the co-sensitization method. This approach is improving the efficiency of DCSSs with a simple, eco-friendly, and low-cost technique. Among the prepared sensitizers, (5-hydroxybenzo[α]phenazin-9-yl)(phenyl) methanone (3c)/N, Cl-CQD demonstrates the highest photovoltaic efficiency with Jsc (1.31 mA cm−2), Voc (0.495 V), FF (0.466), and η (0.303 %). FT-IR, XRD, 13C NMR, 1H NMR, TEM, EDS-Map, AFM, DLS, and PL studies were used to confirm the structure of the synthesized dyes and quantum dots.

Optimization of the structural, optical, and photovoltaic characteristics of a novel ruthenium(III) complex as a photosensitizer for solar cells

A novel ruthenium(III) complex, [Ru(DAP)2(H2O)2]Cl3 (where DAP = 5,6-Diamino-1,3-dimethylpyrimidine-2,4(1H,3H)-dione), was synthesized for potential application as a photosensitizer dye in solar cell. The ruthenium complex was made and precipitated as violet crystals by reaction of K2[RuCl5H2O] with the ligand DAP, in an aqueous ethanol (1:1; v/v)). Elemental analysis, magnetic, thermal, X-ray diffraction, electron scanning microscope and spectroscopic techniques were used for physico-chemical characterizations. Additionally, the electrochemical properties were studied by cyclic voltammetry and voltammogram showed different peaks with different oxidation potentials confirming an extraordinary electrochemical property for the complex. The fabrication of nanostructured films of ruthenium(III) complex was achieved through the thermal evaporation technique, and from which optical and electrical characterizations were studied and interpreted. A solar cell hybridizing organic and inorganic materials, incorporating a ruthenium(III) complex and silicon, was fabricated. The current-voltage characteristic of this cell was measured, and from which the photovoltaic parameters were estimated. The solar cell exhibits a filling factor of 0.40 and an efficiency of 3.58 %.

Synthesis and characterization of new purple and green heterocyclic dyes for dye-sensitized solar cells

Due to the growing demand for energy from industrial activities, solar energy has gained increasing attention globally. In recent years, heterocyclic dyes have gained attention due to their potential use as organic photosensitizers in dye-sensitized solar cells (DSSCs). To develop new and effective synthetic dyes for DSSCs, a study was conducted to create new purple dyes 8-(4-chlorophenyl)-5-(hydroxyimino)-3H-imidazo[4′,5′:3,4]benzo[1,2-c]isoxazol-4(5H)-ylidene)-2-arylacetonitriles. These dyes were synthesized by reacting nitro derivatives of imidazo benzoxazole with arylacetonitriles in an alkaline media. Additionally, new fluorescent heterocyclic systems 3-(4-chlorophenyl)-6H-imidazo[4,5-a]isoxazolo[4,3-c]acridine-7-carbonitriles were obtained by heterocyclization of the purple dyes with SOCl2. The highest yield achieved in the synthesis of the title dyes is 74 %. The structures of the new purple and green heterocyclic dyes were confirmed through elemental analysis and spectroscopic data. The photophysical properties of the dyes were investigated using a UV–visible spectrophotometer and a fluorophotometer. The electrochemical characteristics of the purple dyes and fluorescent heterocyclic systems were also studied using cyclic voltammetry. The geometries of the dyes, as well as their highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels, were determined through theoretical calculations using density functional theory (DFT). Furthermore, the photovoltaic performance parameters of the new dyes were examined by analyzing their incident photon-to-current efficiency (IPCE) spectra and current-voltage (I-V) curves. The experimental results showed that the purple dyes exhibited remarkable photovoltaic performances, up to 6.55 %.

Novel Zinc-porphyrin dyes for dye-sensitized solar cells that enables light capture in the near-ultraviolet and visible range

Two novel Zinc-porphyrin central dyes (T-5 and T-6) containing acetylene moiety have been designed and synthesized for application in dye-sensitized solar cells (DSSCs). The light-harvesting capabilities and photovoltaic performance of these dyes were investigated systematically through comparison of different donor (D) unit. Devices fabricated from phenoxazine (POZ)-based molecule T-5 showed higher short-circuit current (JSC, 11.32 mA cm-2) compared to T-6 which based on phenothiazine (PTZ) (10.1 mA cm-2) under standard global AM 1.5 G solar condition. This is due to the fact that the POZ unit has a greater electron supply capacity than the PTZ unit. The introduction of the acetylene moieties into the molecular structure broadens the light absorption range of the dye molecule to the entire visible range and the near-ultraviolet region. The conclusions of this paper demonstrate that incorporating strong electron donor groups in dye molecules, in synergy with conjugated groups, broadens the spectral range of light absorption, thereby enhancing the performance of the dye device.

The role of secondary donor in thiophene-based azo dyes for dye-sensitized solar cells and non-linear optics

The effect of altering the donating strength of secondary donors at the 4th position of the thiophene ring in a series of dyes labeled AB1 to AB9 is investigated in this study. According to the findings, the orientation of the secondary donor has a considerable impact on molecular planarity, resulting in changes in charge transfer (CT) properties within the thiophene-azo-benzoic acid backbone. The time-dependent density functional theory (TD-DFT) study supports these findings, indicating that the vertical absorption maximum of the dyes increases with the secondary donor's donating strength. From AB1 to AB5, photovoltaic parameters show an increase in DSSC performance. Furthermore, dye@TiO2 cluster experiments suggest the possibility of these dyes interacting with TiO2, resulting in red-shifted absorbance of dye@TiO2 clusters.Theoretical predictions are confirmed by the synthesis of AB1 to AB4, with initial absorption in dimethylformamide (DMF) and energies of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) following a similar pattern as observed in density functional theory (DFT) studies. TGA results show that AB1 to AB4 have remarkable thermal stability, enabling their practical application in DSSCs. The efficiencies of the constructed DSSCs varied, with AB4 having the highest (1.90 ± 0.1) and AB1 having the lowest (1.29 ± 0.1). Secondary donors play a critical role in determining molecular characteristics and device performance, according to the theoretical and experimental DSSC results.

Theoretical exploration of copper based electrolytes for third generation dye sensitized solar cells

Dye-sensitized solar cells (DSSCs) present a promising avenue for addressing the escalating need for clean energy solutions. These innovative cells offer a sustainable approach to meet the rising demands for environmentally friendly power sources. An assessment was conducted on a copper complex containing a hexadentate ligand, serving as a redox shuttle, alongside triphenylamine-based organic dyes in the construction of DSSC. This study thoroughly investigates the electronic structures, FMO, MEP surfaces, and photophysical properties of copper redox shuttle and triphenylamine dyes employing DFT and TDDFT calculations. The copper system, [Cu(bpyPY4)]2+/+, analyzed in this study, is anchored by the hexadentate polypyridyl ligand bpyPY4 (6,6′-bis(1,1-di(pyridine-2-yl)ethyl)-2,2′-bipyridine), scrutinized as a redox shuttle (RS). The assessed redox potential for [Cu(bpyPY4)]2+/+ is −4.67 eV. This indicates that the dye can effectively undergo regeneration by transferring electrons from the reduced form of the redox shuttle to the oxidized form of the dye. The photovoltaic efficiency has been analyzed with regard to various factors, including the energy gap between the HOMO and LUMO, the excited-state oxidation potential (Edye*), electron injection ability (∆Ginj), electron regeneration (∆Greg), light harvesting efficiency, short-circuit current density (JSC) and the open-circuit voltage (Voc). This study sheds light on present-day developments and forthcoming prospects in utilizing 3d transition metal-based redox shuttles, presenting them as compelling candidates for integration with organic dyes in Dye-Sensitized Solar Cells (DSSCs). This integration holds promise for more efficient solar spectrum absorption and enhanced performance of solar devices.

Unlocking the potential of anthocyanin-based dye-sensitized solar cells: Strategies for enhancing efficiency, stability, and economic viability

This study investigates the feasibility and potential of anthocyanins as natural dyes in dye-sensitized solar cells (DSSCs). The focus is on the efficiency, stability, and economic viability of using anthocyanins as green alternatives in renewable energy technology. While anthocyanins offer controlled modification of optical properties at a low cost, there are challenges to overcome in achieving high efficiency, long-term stability, and commercial affordability. The study analyzes recent research developments and proposes strategies to enhance efficiency, stability, and economic viability. Optimization techniques, such as dye mixing and co-pigmentation, as well as modifications to dye structure and protective coatings, are explored. Economic considerations, availability, scalability, and innovative approaches like dye engineering and novel device architectures are discussed. The findings highlight the potential of anthocyanin-based DSSCs as a sustainable and economically viable solar energy technology. The study concludes with recommendations for future research to overcome challenges and advance the field of anthocyanin-based DSSCs.

DFT and TD-DFT study of substituent effects on structure, spectroscopic and photoelectric characteristics of D-A dyes for solar cells

To study the structure, photophysical and photoelectric properties of chlorophyll derivatives, the chlorophyll derivative dyes (CHL-1 and CHL-6) were investigated to exploit their utility in solar cells. The two experimental dye systems were simulated using DFT and TD-DFT, and optimization of the structure, absorption spectroscopy, chemical parameters, electron transfer, and dye regeneration processes were studied to analyze their different performance. Furthermore, a functional group substitution strategy was adopted to improve PCE, and the electron-withdrawing groups were introduced into the acceptor group of CHL-6 to design new chlorophyll derivative molecules, in which the high efficiency for designed molecule CN-1 is 1.19 times that of the experimental molecule CHL-6. This study provides insights into the optoelectronic properties of chlorophyll derivatives, and introducing specific electron-withdrawing groups in the acceptor fraction helps to improve photoelectric efficiency.

Effects of Several Auxiliary Acceptors and Anchoring Groups on Charge Transfer and Photophysical Properties of D-A-π-A Type DSSCs: A DFT Study.

In this paper, we performed theoretical studies on the twelve D-A-π-A type organic dyes (G-1 ~ G-3, M-1 ~ M-3, J-1 ~ J-3, and S-1 ~ S-3) with 9-phenylcarbazole as the electron donor in anticipation of the application of these dyes in dye-sensitized solar cells (DSSCs). DFT and TD-DFT methods are applied to investigate in detail the molecular geometries, frontier molecular orbitals (FMOs), absorption spectra, charge density difference (CDD), and transition density matrix (TDM) of several dyes. The results show that the M-series (M-1 ~ M-3) dyes have the largest dihedral angles between the electron donor and the auxiliary acceptor and also has the largest energy gaps in HOMO-LUMO orbitals, which greatly reduces the charge transfer efficiency. Finally, the UV-Vis absorption spectra inferred that the anchoring groups modified with o-nitrobenzoic acid (G-3, M-3, J-3, S-3) can red-shift the absorption peaks of the dyes, which results in higher light-harvesting efficiency and improves the power conversion efficiency of DSSCs. Overall, all of these dyes contribute to the improvement of photovoltaic power conversion efficiency and have potential for application in DSSCs devices.

Application of machine learning-based read-across structure-property relationship (RASPR) as a new tool for predictive modelling: Prediction of power conversion efficiency (PCE) for selected classes of organic dyes in dye-sensitized solar cells (DSSCs).

The application of various in-silico-based approaches for the prediction of various properties of materials has been an effective alternative to experimental methods. Recently, the concepts of Quantitative structure-property relationship (QSPR) and read-across (RA) methods were merged to develop a new emerging chemoinformatic tool: read-across structure-property relationship (RASPR). The RASPR method can be applicable to both large and small datasets as it uses various similarity and error-based measures. It has also been observed that RASPR models tend to have an increased external predictivity compared to the corresponding QSPR models. In this study, we have modeled the power conversion efficiency (PCE) of organic dyes used in dye-sensitized solar cells (DSSCs) by using the quantitative RASPR (q-RASPR) method. We have used relatively larger classes of organic dyes-Phenothiazines (n=207), Porphyrins (n=281), and Triphenylamines (n=229) for the modelling purpose. We have divided each of the datasets into training and test sets in 3 different combinations, and with the training sets we have developed three different QSPR models with structural and physicochemical descriptors and validated them with the corresponding test sets. These corresponding modeled descriptors were used to calculate the RASPR descriptors using a Java-based tool RASAR Descriptor Calculator v2.0 (https://sites.google.com/jadavpuruniversity.in/dtc-lab-software/home), and then data fusion was performed by pooling the previously selected structural and physicochemical descriptors with the calculated RASPR descriptors. Further feature selection algorithm was employed to develop the final RASPR PLS models. Here, we also developed different machine learning (ML) models with the descriptors selected in the QSPR PLS and RASPR PLS models, and it was found that models with RASPR descriptors superseded in external predictivity the models with only structural and physicochemical descriptors: RMSEP reduced for phenothiazines from 1.16-1.25 to 1.07-1.18, for porphyrins from 1.60-1.79 to 1.45-1.53, for triphenylamines from 1.27-1.54 to 1.20-1.47.

Investigating the Effects of Fluorine Substituents on Organic Dyes in Dye-Sensitized Solar Cells

We synthesized and evaluated five organic dyes that featured both mono- and di-substituted fluorine atoms for application in dye-sensitized solar cells (DSSCs). The dye structure was designed with N, N-dimethylaniline as a donor, fluorophenyl as an π-conjugated bridge, and cyanoacetic acid as an anchoring and acceptor group. The fluorine substituents are strong electron-withdrawing groups, introducing different numbers and positions of fluorine atoms (ortho and meta) that were expected to the ability of the acceptor parts of the dye. The results showed that adding the fluorine mono-substitution in the ortho position can enhance the efficiency of the solar cells in comparison with the meta-substitution and unsubstituted one. However, the di-substitution by fluorine atoms in two ortho positions and ortho, meta positions reduced the performance of the solar cells. The reason was related to the effect of π-conjugation between the fluorine substituent and the carbonyl group of the carboxylic acid. The DSSCs based on dye 14 achieved the best results with power conversion efficiency (PCE) = 3.33%, (Jsc = 5.43 mA cm-2, Voc = 0.81V and FF = 75.85%) under standard conditions with I3-/I- as the electrolyte.