Performance Of Dye-sensitized Solar Cells Research Articles

Design and construction of MoS2/Ni3S2 nanosheets decorated on multi-walled carbon nanotubes as a sustainable counter electrode for dye-sensitized solar cells: An experimental and computational investigation

To achieve a satisfactory photovoltaic performance in dye-sensitized solar cells (DSSCs), counter electrode (CE) catalysts with low cost, superior catalytic activity and excellent conductivity should be developed. Herein, we successfully prepared the MoS2/Ni3S2 heterostructures via the hydrothermal method and decorated on multi-walled carbon nanotubes (MWCNTs) by sonication method. The performance of the prepared CEs was investigated by various electrochemical techniques. Based on the electrochemical tests, the MoS2/Ni3S2/MWCNTs ternary nanocomposite displayed high electron transfer ability, remarkable catalytic activities, and good stability in the I3−/I− electrolyte. The power conversion efficiency (PCE) of DSSCs based on MoS2/Ni3S2/MWCNTs CE reached 8.27 %, which was even higher than that of the DSSC with Pt CE (7.23 %). The excellent performance of the catalyst is related to the structural properties, synergistic effect of MoS2/Ni3S2 and MWCNTs, and high porosity of MoS2/Ni3S2/MWCNTs composite. The results of calculations indicated that by decorating the MoS2/Ni3S2 on carbon nanotubes (CNTs), the bandgap decreased to 2.79 eV, which was smaller than the individual CNTs (6.27 eV). This finding depicted that synergistic effect between MoS2/Ni3S2 and MWCNTs can reduce the bandgap of MoS2/Ni3S2/MWCNTs composite. The lower bandgap mostly results in higher electrical conductivity and lower charge-transfer resistance, which plays an important role in improving the efficiency of DSSCs.

Synergistic Co-sensitization: Unlocking the potential of carbohydrazide chromophores and metal complexes for high-performance dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) have emerged as a promising alternative to traditional silicon-based photovoltaic devices due to their low-cost fabrication and tunable optical properties. One effective strategy to improve the light-harvesting capabilities of DSSCs is co-sensitization, which involves combining multiple dyes with complementary absorption properties. In this study, we report the co-sensitization of carbohydrazide-based organic chromophores, namely MRK-1–2, with a benchmark metal-complex dye (black dye) to enhance the photovoltaic performance of DSSCs. The synthesis of MRK-1–2 sensitizers is described, and their photophysical properties are thoroughly analyzed. The absorption spectra of the co-sensitizers revealed distinct absorption bands associated with intramolecular charge transfer and localized aromatic π-π* transitions. Sensitization by MRK-1–2 resulted in photovoltaic efficiencies ranging between 5.02–5.88 %. The ternary co-sensitization system of carbohydrazide-based chromophores (MRK-1–2 + black dye) showed promising potential for enhancing the short-circuit current density (JSC) (20.32–21.45 mA/cm2), open-circuit voltage VOC (691–729 mV), and overall power conversion efficiency (PCE) (9.52–9.90 %). This significant improvement in photovoltaic performance is attributed to the complementary light-harvesting abilities of the co-sensitizers, leading to enhanced light absorption and efficient charge separation and injection processes. The superior performance, with a (PCE) of up to 9.90 %, can be attributed to complementary light absorption, efficient charge injection facilitated by the carboxylic acid moiety in MRK-2, and suppressed charge recombination within the co-sensitized system. The findings of this study will contribute to the advancement of DSSC technologies and bring us closer to sustainable and renewable energy solutions.

Characterization and Application of Natural Photosensitizer and Poly(vinylidene Fluoride) Nanofiber Membranes-Based Electrolytes in DSSC

This comprehensive research has explored the potential of enhancing dye-sensitized solar cells (DSSC) by harnessing environmentally friendly natural dyes, such as chlorophyll pigments from pandanus (664.1 nm) and papaya leaves (664.0 nm), as well as betacyanin pigments from sappan-mangosteen (536.2 nm). Electrochemical analyses elucidated the energy band gaps, revealing a hierarchy with the smallest band gap observed for papaya leaves (1.387 eV), followed closely by sappan-mangosteen (1.389 eV) and pandan leaves (1.396 eV). This research effectively addressed the persistent issue of electrolyte leakage in DSSC development by introducing a polymer electrolyte derived from polyvinylidene fluoride (PVDF) through electrospinning and phase inversion techniques. SEM characterization results and thermogravimetric analysis underscored the superior characteristics and high thermal stability of the PVDF nanofiber polymer for DSSC applications. The study's pivotal findings underscore the remarkable DSSC performance achieved with chlorophyll pigment from papaya leaves, reaching 1.31% efficiency without a polymer electrolyte. Moreover, the sappan-mangosteen dye emerged as a promising contender with the highest efficiency values when applied with polymer electrolyte, recording rates of 1.17% for PVDF NF and 0.95% for PVDF, which are notably comparable to the efficiency of liquid electrolyte at 1.26%.

Influence of surface passivation by MgO on photovoltaic performance of SnO2 based dye-sensitized solar cells

The study highlights effect of surface modification of SnO2 photoelectrode by MgO coating on photovoltaic properties of dye-sensitized solar cells (DSSCs). A thin coating of MgO on SnO2 photoelectrode was prepared using sol-gel-derived dip coating technique. The bare SnO2 and MgO coated SnO2 composite photoanodes was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and UV–vis spectrophotometer. The optical absorption study revealed that the modification in SnO2 by MgO coating caused an increase in absorption by photoanode in visible region. The solar cell was demonstrated by preparing FTO|SnO2|Dye|MgO|Electrolyte|Pt coated FTO device structure and tested with current density-voltage (J-V) measurement. The effect of precursor concentration of MgO coating on the performance of DSSCs were investigated. It was found that, optimized coating of MgO for 90 seconds on SnO2 improved all photovoltaic parameters, resulting in enhancement in efficiency by 42% compared to that of DSSC with bare SnO2 photoanode. The coating of MgO would have reduced the trap states and suppressed interfacial recombination losses by preventing back electron transfer from the conduction band of the semiconductor to HOMO of dye molecule or redox species.

Towards sustainable solar cells: unveiling the latest developments in bio-nano materials for enhanced DSSC efficiency

Abstract Fossil fuels—instrumental in powering the nineteenth-century Industrial Revolution—are now under heightened scrutiny due to environmental concerns and carbon emissions. Consequently, there is a global impetus towards achieving carbon-neutral energy production, with solar energy emerging as a cornerstone in this transition. Over the past three decades, dye-sensitized solar cells (DSSCs) have gained increasing prominence due to their unique advantages. This review elucidates several crucial elements essential to DSSC construction, notably bio-nano materials, prized for their structural flexibility, cost-effectiveness and high molar absorption coefficient. It delves into the intricate relationship between molecular structure and DSSC performance, showcasing significant advancements with light-to-power conversion efficiencies reaching 11%. A comprehensive analysis of the photovoltaic performance of DSSCs utilizing bio-nano-based dyes offers invaluable insights into the state of this rapidly evolving industry. Key components under scrutiny include transparent conductive oxide (TCO) layers, physical techniques for metal oxide deposition onto TCO thin films, diverse dye variants and foundational knowledge of components ripe for growth and enhancement. Moreover, the review outlines the latest breakthroughs in the field, providing glimpses into the current status of prototype DSSCs.

Active carbon derived from rice husk as sustainable substitutes for costly platinum electrodes in dye-sensitized solar cells

Significant financial and environmental challenges are associated with using platinum electrodes as counter electrodes (CEs) in dye-sensitized solar cells (DSCs). This work uses rice husk, an agricultural waste, to create active carbon that is appropriate for DSC CEs in response to these difficulties. A simple spray pyrolysis technique created activated carbon obtained from rice husks. The DSC employing activated rice husk carbon as the CE demonstrated a conversion efficiency of 6.06%, slightly lower than the 8.21% efficiency achieved with a platinum electrode-based cell. However, this performance gap is overshadowed by the substantial cost reduction enabled by the utilization of low-cost activated carbon compared to noble metal alternatives. This result introduces promising avenues for investigating the use of agriculturally derived carbon materials as workable and affordable options for platinum CEs in DSCs, thereby contributing to the sustainable advancement of photovoltaic systems. Even though the performance of DSC that uses activated carbon derived from rice husk in CE is slightly lower than its counterparts based on platinum, the cost reduction due to the use of low-cost activated carbon with noble metal is significant.

Synthesis of TiO2 nanoparticles by green approach: Application as photoanode for dye-sensitized solar cells

Efficient photoanodes play a central role in the performance of dye-sensitized solar cells. Traditional methods for synthesizing TiO2 often involve chemical processes that can be expensive and environmentally harmful due to the use of toxic and hazardous substances. Therefore in this work, TiO2 nanoparticles (NPs) were synthesized using bio-inspired processing through a hydrothermal procedure using different concentrations of Aloe barbadensis miller leaves extract as the reducing and stabilizing agent. Scanning electron microscopy (SEM), UV–vis spectroscopy (UV), X-ray difraction (XRD), Raman Spectroscopy, transmission electron microscopy (TEM) and Brunauer–Emmett–Teller (BET) analysis were used to characterize as synthesized TiO2 NPs. DSSCs were fabricated employing the prepared TiO2 NPs as photoanodes, and their performance was assessed. DSSC generates JSC of 9.7 mA/cm2, VOC of 0.682 V and efficiency (η) of 4.3 % when 20 mL concentration of extract was used for the synthesis of TiO2 NPs and subsequently their photoanodes.

Enhancing dye-sensitized solar cell performance: Optimizing Cu2ZnSnS4/ZnCo2O4 nanocomposites as efficient and cost-effective counter electrodes

This study investigates the utilization of Cu2ZnSnS4/ZnCo2O4 (CZTS/ZCO) nanocomposites prepared through hydrothermal and combustion methods as counter electrodes in Dye-Sensitized Solar Cells (DSSCs). Different ratios of Cu2ZnSnS4 and ZnCo2O4 were explored, and comprehensive analyses were conducted using X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), High-Resolution TEM (HRTEM), Brunauer–Emmett–Teller (BET) surface area analysis, Raman Spectroscopy, Electrochemical Impedance Spectroscopy (EIS), cyclic voltammetry (CV), Tafel analysis, Field Emission Scanning Electron Microscopy (FESEM), and Incident Photon-to-Electron Conversion Efficiency (IPCE), alongside long-term stability assessments. The CZTS:ZCO ratio of 2:1 exhibited the highest efficiency, reaching 8.81 %, with an open-circuit voltage of 729 mV, short-circuit current of 17.80 mAcm−2, and a fill factor of 67.9 %. This surpasses the efficiency of the reference Pt cell (8.42 %), which had an open-circuit voltage of 735 mV, short-circuit current of 17.16 mAcm−2, and a fill factor of 66.8 %. The average crystallite sizes for the main peaks of CZTS and ZCO samples were estimated to be 19.8 and 16.7 nm, respectively. The crystallite size can significantly affect the charge transfer and conductivity in the counter electrode during electrochemical processes; the presence of nanocrystals with these sizes can notably enhance the electrochemical properties and conductivity of the synthesized samples. Raman analysis results indicate that no additional phases or secondary phases such as ZnS and CuSnS3 have formed in the kesterite CZTS structure, and the crystal has formed as a single phase. Additionally, the F2g modes in the Raman spectrum of ZCO indicate tetrahedral units in the spinel ZCO structure, and the A1g modes represent octahedral structures in this phase, indicating the formation of suitable ZCO phase. The superior performance of the CZTS/ZCO nanocomposite can be attributed to its enhanced crystalline structure, superior charge transport characteristics, and improved electrocatalytic behaviours.

How Components of Dye-sensitized Solar Cells Contribute to Efficient Solar Energy Capture

Herein, we reviewed the main components of dye-sensitized solar cells (DSSCs) which are an emerging cheap and environmentally benign alternative for solar energy capture and conversion to electricity. The role of individual parts such as the semiconductor electrode, counter electrode, photosensitizer, electrolyte, and substrate and their contribution to the overall efficiency (η) of DSSCs are discussed. In addition, parameters such as short circuit current, open circuit voltage, and fill factor used to quantify the efficiency of DSSCs are addressed. The highest solar-to-electric energy conversion efficiency of 13 % has been achieved using titanium dioxide as a semiconductor electrode, a triiodide system as a redox couple, and platinum counter electrodes. Semiconductors are made up of materials such as glass, carbon, conductive polymers and other metal oxides have lower efficiencies (< 8 %). In addition, synthetic photosensitizers especially ruthenium complexes have higher efficiencies (10-11 %) compared to natural dyes among which the highest efficiency (4.6 %) was achieved using chlorophyll. The performance of natural dyes based on efficiency of the DSSC is generally in the order: chlorophyll > anthocyanins > carotenoids that is highly attributed to their structure which not only dictates electron release and recombination but also attachment to other components. The DSSC performance is not fixed but rather tunable by variations in the components to achieve desired structural and electronic properties such as firm anchorage between the photosensitizer and the semiconductors, the reduction of the energy band gap by incorporation of other metal salts to extend the absorption range and use of additives that prevent electron recombination with the photosensitizer or any hindrances in the electrolyte redox reactions.

Synergistic effects of polyvinylidene fluoride (PVDF) and polyvinylpyrrolidone (PVP) blends in gel electrolytes for efficient and long-term stability in dye-sensitized solar cells (DSSCs)

In this work, the stability issues associated with liquid electrolyte-based dye-sensitized solar cells (DSSC) have been addressed by introducing polymer gel electrolytes. The synergistic combination of polyvinylidene fluoride (PVDF) and polyvinylpyrrolidone (PVP) has been achieved through solution blending. Ionic conductivity measurements, scanning electron microscopy, X-ray diffraction analysis, and Fourier transform infrared spectroscopy have been employed for analysis. Optimal cohesiveness was observed at PVP concentrations exceeding 40 %, with the best outcomes achieved at a 50 % PVDF-PVP weight ratio. The electrolyte solution, comprising the polymer blend, suitable solvents, and iodine-based salts, exhibits peak conductivity (2.33 mScm⁻1) at a 10 % salt content. DSSCs utilizing the PVDF & PVP polymer blend gel electrolytes demonstrate enhanced durability and maintained efficiency at 5.43 %, exhibiting only a modest 12 % reduction compared to liquid electrolyte counterparts. Over two weeks, the fabricated DSSCs exhibited consistent photovoltaic performance, while conventional cells experienced significant declines in short-circuit current (36 %) and open-circuit voltage (33.33 %). This study signifies a promising advancement in solar cell technology, showcasing improved stability and performance in DSSCs using conductive polymer blend gel electrolytes.

Optimization of electrolyte co-additives, TiO2 thickness, and dye concentration for the enhanced performance of dye-sensitized solar cells

Optimization of electrolyte co-additives, TiO2 thickness, and dye concentration for the enhanced performance of dye-sensitized solar cells

Influence of photoanode pre-heating treatment temperatures prior to dye immersion process on dye-sensitized solar cells photovoltaic performances

Several efforts of photoanode treatment, such as surface modification, doping introduction, defect engineering, and heating treatment, have been developed to improve the photovoltaic performances of dye-sensitized solar cells (DSSC). Amid these options, alternative routes that require less demanding conditions are highly sought. Here we introduce an effective and convenient, non-vacuum low-temperature procedure to enhance the DSSC’s photovoltaic performances by photoanode pre-heating treatment prior to the dye immersion process. The experimental result showed that pre-heating treatment at 120 °C improves the efficiency and short-circuit current by about 28.4% and 19.1%, respectively. The conducted transient photovoltage measurements revealed that the increase of pre-heating temperatures leads to a longer electron lifetime and higher charge collection efficiency.

Revolutionizing dye-sensitized solar cells with nanomaterials for enhanced photoelectric performance

Dye-sensitized solar cells have emerged as a promising alternative to conventional solar cells due to their cost-effectiveness and ease of fabrication. In recent years, the integration of nanomaterials into dye-sensitized solar cells has garnered substantial attention, offering new avenues to enhance their photoelectric performance. This review comprehensively examines the role of nanomaterials in elevating the efficiency and functionality of dye-sensitized solar cells. The fundamental principles of dye-sensitized solar cells are introduced, emphasizing the intricate interplay between crucial components that enable light absorption, charge separation, and electron transport. Nanomaterials play important roles across the entire spectrum of photoelectric conversion of dye-sensitized solar cells, e.g., constructing light-trapping architectures, creating interlayer transmission bridges, and facilitating charge carrier transport pathways, thus offering cost-effective alternatives to precious metals. Furthermore, this review concludes the central role of nanomaterials in shaping the landscape of flexible optoelectronic materials, highlighting their paramount importance in this area. The extensive scientific insights presented herein not only showcase the cutting-edge achievements in solar energy conversion efficiency but also serve as a comprehensive guide for the proper selection of nanomaterials. Finally, this work outlines the forthcoming challenges and offers insights into promising research avenues based on a comprehensive examination of various scholarly pursuits. Unlike other reviews that focus on the analyses of structures or components, this review concentrates on the impact of nanomaterials on the overall photoelectric performance of dye-sensitized solar cells. By fostering cross-disciplinary collaboration and advancing relevant research, dye-sensitized solar cells hold promise as a significant contributor to the global transition toward clean and renewable energy sources.

Enhanced photovoltaic performance of dye sensitized solar cells using cesium bromide modified TiO2 electron transport layer

TiO2 is one of the most widely explored materials as an electron transport layer (ETL) in dye sensitized solar cells (DSSCs) due to its excellent physical and chemical properties. However, recombination at the device's interface slackens the charge carrier movement, adversely affecting their device performance. Rapid extraction of photogenerated charge carriers plays a vital role in developing high efficiency DSSCs. The conduction band alignment of TiO2 ETL and N719 dye light absorber plays a crucial role in charge carrier dynamics of DSSCs. Herein, the band structure of TiO2 ETL is finely tuned by the incorporation of cesium bromide (CsBr). At the optimal concentration (0.4 Wt. %), DSSCs achieved the best power conversion efficiency (PCE) of 9.28 % compared to 7.61 % for pristine TiO2. The modified TiO2–CsBr ETL induced a negative shift in flat band potential (Vfb) from −0.46 to −0.50 V, which improved the open circuit voltage (VOC), its work function (ɸ) from −4.71 to −3.75 eV and increased conduction band minimum (CBM) from −3.58 to −2.42 eV. CsBr incorporation increased electron density in TiO2 matrix, indicating the suppression of trap state and significantly improved the overall photovoltaic performance of DSSCs.

Dye-sensitized solar cell: Effect of light on N3 dye/BMII electrolyte based architecture

This study evaluates the photovoltaic performance of Dye-Sensitized Solar Cells (DSSCs) for various light conditions. This work focuses on exploring the experimental characteristics of a thin-film solar cell composed of an ITO/TiO2/N3-Dye and BMII electrolyte molecules/Pt/ITO. A meticulous investigation is conducted to understand the impact of different illumination intensities on the efficiency of these solar cells. In the experiments, the power conversion efficiencies (PCE) of the device reached 7.61 % with a maximum open-circuit voltage (Voc) of 0.67 V under 100 mW/cm2 AM 1.5 solar irradiance. The morphology of the TiO2 nanoparticles that have been synthesized for the DSSC were analyzed by Ultraviolet–Visible Spectrometry, X-Ray Diffractometry, as well as Scanning Electron Microscopy and Atomic Force Microscopy. Electrochemical impedance spectroscopy (EIS) parameters and Nyquist plot results showed that a systematic understanding of charge transfer within the DSSC is essential to extract an equivalent circuit model. The results of this study allow optimizing the performance of future DSSCs for sustainable energy systems.

A study on using a binder-free TiO2 paste with sodium dodecylbenzene sulfonate addition to improve the performance of low-temperature DSSCs

The utilization of binder-free TiO2 paste allows for the dye-sensitized solar cells (DSSCs) TiO2 electrode fabrication at low temperatures, thus making it a potential material for flexible solar cell devices. However, the physical robustness of formed electrodes using TiO2 paste at low temperatures remains challenging, including issues such as cracking due to film stress and challenges in adjusting the viscosity of the TiO2 paste. In this study, we enhanced the binder-free TiO2 paste performance by incorporating sodium dodecylbenzene sulfonate (SDBS) as an additive for TiO2 electrode precursor solution. It demonstrated that SDBS additives help to relieve internal stress and ultimately enhance the physical and structural characteristics of the films by improving the viscosity in the TiO2 paste and promoting the dispersed pinholes within the TiO2 films. Furthermore, implementing TiO2 paste with varying ratios of SDBS has enabled the fabrication of DSSCs with the highest achieved power conversion efficiency (PCE) of 4.53%, representing an enhancement of nearly 15% compared to TiO2 paste without SDBS. This research presents a practical and effective approach for preparing highly efficient binder-free TiO2 paste.

Effect of Size and Morphology of Different ZnO Nanostructures on the Performance of Dye-Sensitized Solar Cells

In this study, the influence of zinc oxide (ZnO) nanostructures with various morphologies on the performance of dye-sensitized solar cells (DSSCs) was investigated. Photo-electrodes were fabricated incorporating ZnO transport layers of distinct nanoscale morphologies—namely nanoparticles, microballs, spiky microballs, belts, and triangles—and their respective current–voltage characteristics were evaluated. It was observed that the DSSCs employing the triangular ZnO nanostructures, with a side length of approximately 30 nm, achieved the highest power conversion efficiency of 2.62%. This was closely followed by the DSSCs using spherical nanoparticles with an average diameter of approximately 20 nm, yielding an efficiency of 2.54%. In contrast, the efficiencies of DSSCs with microball and spiky microball ZnO nanostructures were significantly lower, measuring 0.31 and 1.79%, respectively. The reduction in efficiency for the microball-based DSSCs is attributed to the formation of micro-cracks within the thin film during the fabrication process. All DSSC configurations maintained a uniform active area of 4 mm². Remarkably, the highest fill factor of 59.88% was recorded for DSSCs utilizing the triangular ZnO morphology, with the spherical nanoparticles attaining a marginally lower fill factor of 59.38%. This investigation corroborates the hypothesis that reduced particle size in the transport layer correlates with enhanced DSSC performance, which is further amplified when the nanoparticles possess pointed geometries that induce strong electric fields due to elevated charge concentrations.

Enhanced dye-sensitized solar cell performance and electrochemical capacitive behavior of bi-functional ZnO/NiO/Co3O4 ternary nanocomposite prepared by chemical co-precipitation method

Increasing prerequisites for sustainable energy storage and conversion technologies have necessitated the exploration of advanced materials with improved properties. Here, we present the synthesis and characterization of ZnO nanoparticles (NPs), ZnO/NiO, ZnO/Co3O4 and ZnO/NiO/Co3O4 NCs as promising bi-functional materials for dye-sensitized solar cell (DSSC) and electrochemical energy storage applications. A facile chemical co-precipitation approach was followed to synthesize pure ZnO NPs, ZnO/NiO, ZnO/Co3O4 and ZnO/NiO/Co3O4 NCs. The structural and morphological analyses revealed the successful integration of ZnO, NiO, and Co3O4 NPs and also the formation of well-defined core-shell and homogenous nanocomposite structures. The XRD and HRTEM analyses confirmed the crystalline nature and nanoscale morphology of synthesized materials, respectively. The photovoltaic performance of DSSC fabricated using ternary ZnO/NiO/Co3O4 NC photoanode showed optimum dye-loading and best solar to electrical energy conversion efficiency with Jsc of 11.29 mA cm−2 and ƞ of 4.66%, which was considerably higher than the DSSC fabricated using pure ZnO NPs photoanode (ƞ = 2.01%). The increment in photocurrent density (Jsc) could be ascribed to the perfect band alignment of NiO and Co3O4 NPs in the ternary NC. Further, the ZnO/NiO/Co3O4 NC photoanode integrated DSSC disclosed 97% retainment in energy conversion efficiency even after 10 days of operation. The electrochemical performance of supercapacitor fabricated using ternary ZnO/NiO/Co3O4 NC showed high specific capacitance of 534.7 Fg−1 at 1 Ag−1 with favourable rate ability (∼52% at 16 Ag−1), good cyclic stability (91.07%) and low internal resistance. Moreover, the ZnO/NiO/Co3O4 NC at a current density of 2 Ag−1 exhibited a significantly high capacitance value of 463.1 Fg−1, which was 1.93, 1.58 and 1.22 times greater than ZnO NPs, ZnO/Co3O4 NC and ZnO/NiO NC, respectively.

Poly(triphenylamine-thiazolo[5,4-d]thiazole) copolymer dyes with different anchoring end groups: Synthesis, dye-sensitized solar cell (DSSC) performance and femtosecond excited state absorption spectroscopy

In this study, the poly(triphenylaminethiazolo[5,4-d]thiazole) copolymer dyes having the different anchoring end groups of aldehyde (poly-TPATT-CHO; P5), sulfonic acid (poly-TPATT-SO3H; P5S) and cyanoacrylic acid (poly-TPATT-COOH; P5C) have been synthesized and used as sensitizers in dye-sensitized solar cells (DSSCs). The effects of the anchoring end groups of the P5, P5S and P5C copolymer dyes on the DSSC performance were examined. The synthesized copolymer dyes were characterized using 1H NMR, UV–vis. absorption and fluorescence (FL) emission spectroscopy, cyclic voltammetry (CV), MALDI-TOF-MS and FE-SEM-EDS methods. Among the studied polymers, the P5C polymer dye exhibited the best photovoltaic performance with a JSC of 6.46 mA cm−2, a VOC of 0.667 V, a FF of 0.70, and an overall power conversion efficiency (PCE) of 3.02 % under standard AM 1.5 G solar light conditions. These results are attributed to the strong binding ability of cyanoacrylic acid to the TiO2, leading to a greater photocurrent and hindered charge recombination. The effect of electron transfer mechanisms of the polymers on the DSSC performance have been investigated using the femtosecond transient absorption (fs TA) spectroscopy. The DSSC performance of the poly(triphenylaminethiazolo[5,4-d]thiazole) increased greatly by the presence of the cyanoacrylic acid anchoring end group in P5C polymer dye. The fs TA spectroscopy results revealed the presence of singlet–triplet transition for the P5C copolymer dye, while the P5 and P5S copolymers showed only singlet–singlet transitions. The observed triplet state transition in the P5C polymer increased the yield of the DSSC system.

Morphological and Compositional Study of Nitrogen-TiO₂ Anchored Composite with Azo Dyes in a DSSC

The efficiency of Dye-Sensitized Solar Cells (DSSCs) heavily relies on the structural and morphological characteristics of the photoanode materials [1]. This study investigates the effects of Nitrogen on TiO2 and the subsequent anchoring with two different Azo dyes RP and VC, to evaluate their impact on DSSC performance [2]. A comprehensive analysis was conducted using Scanning Electron Microscopy (SEM) to study the surface morphology of pure TiO2, Nitrogen TiO2 (N-TiO2), and N-TiO2 composites with RP and VC Azo dyes [3]. Energy-Dispersive X-Ray Spectroscopy (EDS) provided insight into the elemental composition and confirmed the successful incorporation of nitrogen into the TiO2 structure. The SEM images reveal significant morphological differences between the pure and N-TiO2 samples, as well as changes induced by the azo dye anchoring [4]. The Nitrogen incorporation was found to increase surface roughness and enhance dye adsorption [5]. A comparative analysis of the N-TiO2 composite with RP and VC azo dyes highlights variations in dye distribution and surface coverage, which may influence light absorption and charge transfer efficiency. The findings provide valuable insights into the design of optimized photoanode materials, aiming to improve the photovoltaic performance of DSSCs [6].