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- 2019
- Dye-sensitized solar cell
- Photoelectrode
- Light scattering layer
- Transmittance
- White pigment (R902+)
- Rutile titanium dioxide
- Optoelectronic Information Materials and Devices
- Tribhuvan University
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Alkyl Group Wrapped Unsymmetrical Squaraine Dyes for Dye-sensitized Solar Cells: Branched Alkyl Chains Modulate the Aggregation of Dyes and Charge Recombination Processes
摘要： Electron transfer processes at the interfaces dictate the factors to improve the photovoltaic parameters such as open-circuit voltage (Voc) and short-circuit current (Jsc) of a dye-sensitized solar cell (DSSC) device besides selecting a set of suitable anode, dye, electrolyte and cathode materials. Inefficient charge injection process at dye-TiO2 interface and charge recombination at the TiO2-dye/electrolyte interface have detrimental effects in improving both Jsc and Voc. Hence tailoring the factors that governs to improve the Jsc and Voc will be an ideal approach to get the desired sensitizers with good device efficiencies. Squaraines are far-red active zwitterionic dyes, has high molar extinction coefficient along with unique aggregation properties due to the larger dipole moment associated with it. Here we report a series of unsymmetrical squaraine dyes, SQS1 to SQS6, with systematic variation of alkyl groups at sp3-C and N-atoms of indoline unit that was away from the anchoring group to control the dye-dye interactions on the TiO2 surface. The branched alkyl groups help to modulate the self-assembly of sensitizers on the TiO2 surface besides passivating the surface that helps to avoid the charge recombination processes. Light harvesting efficiency (LHE) and cyclic voltammetry studies of dye-sensitized TiO2 electrode indicated that the aggregation and charge hopping process between the dye molecules can be modulated, respectively by systematically increasing the number of carbon atoms in the alkyl groups. Such variation in the branched alkyl group helps to enhance the Voc from 672 (SQS1) to 718 mV (SQS6), Jsc from 7.95 (SQS1) to 12.22 mA/cm2 (SQS6), with the device efficiency ranging from 3.82% to 6.23% without any coadsorbent. Dye SQS4 has achieved highest efficiency of 7.1% (Voc = 715 mV, Jsc = 13.05 mA/cm2) with coadsorbent chenodeoxycholic acid (CDCA) using iodine (I-/I3 -) electrolyte compared to its analogs. Analysis of IPCE profile indicates that the major contribution of photocurrent generation is from the aggregated squaraine dyes on TiO2.
关键词： Un-symmetrical squaraines,charge recombination,charge injection,aggregation of dye,dye-sensitized solar cells
更新于2025-09-12 10:27:22
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Cobalt complex dye as a novel sensitizer in dye sensitized solar cells
摘要： In this study, cobalt metal complex has been introduced as a novel class of sensitizer for more mechanistic consideration of the photovoltaic conversion efficiency (PCE) of dye sensitized solar cells. UV-Vis spectroscopy of dye illustrates maximum absorption at wavelengths of dye in 498 and 650 nm. TiO2 was used as the photoanode of the cell whose X-ray diffraction spectrum indicates that its crystal phase is anatase (101). Surface morphology of photoanode was also investigated by scanning electron microscopy (SEM) and obviously showed ~25nm TiO2 nanoparticles. The cyclic voltammetry (CV) investigation of Pt-coated fluorine doped tin oxide (FTO) as the counter electrode of the cell indicates redox process on this electrode. Photovoltaic measurements of cobalt complex sensitized solar cell show that the short-circuit current density (JSC), open-circuit voltage (VOC), fill factor (FF%) and photovoltaic conversion efficiency (PCE%) are 48.80 μA.cm-2, 0.7 V, 44% and 0.09% at the air mass 1.5 (100mW.cm-2) irradiation condition, respectively. The high light harvesting efficiency (LHE) (~61%) and high molar absorption coefficient of the cobalt complex dye (12,500 M-1.cm-1) were other optical advantages of the cobalt complex sensitized solar cell. The results indicate the quantum yield of electron injection (φing) which depends on dye structure as a parameter influences the JSC. The pyridine rings conformation in donor part of the cobalt complex dye plays a significant role in φing and subsequently PCE. These findings open a new insight about mechanistic aspects of dye sensitized solar cells efficiency.
关键词： Dye-sensitized solar cell,Photoanode,Dye,Counter electrode,Photovoltaic measurement,Cobalt complex
更新于2025-09-12 10:27:22
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Interfacial Engineering in Functional Materials for Dye‐Sensitized Solar Cells || Function of <scp>TiCl</scp><sub/>4</sub> Posttreatment in Photoanode
摘要： Energy is the key factor for any living creature to exist in this universe. The advent of industrialization and increase in population have led to a surge in the crisis for energy. The reduction of our dependence on fossil fuels (oil, coal, and natural gas), as well as the evolution towards a cleaner future, requires the large deployment of sustainable renewable energy sources. Among them solar energy is the most abundant and also available throughout the year. Moreover, the solar energy has the greatest potential to fulfill the thirst for energy and the need for innovation of clean and eco-friendly technologies. In this perspective, developing solar cells is one of the best approaches to convert solar energy into electrical energy based on photovoltaic effect. Solar cells based on crystalline silicon and thin film technologies are often referred to as first- and second-generation solar cells. The demerits in that are the limited availability and the cost of silicon. An emerging third-generation photovoltaics have been developed as an alternate to it. These include Dye-sensitized solar cells (DSSCs), organic photovoltaic, quantum dots and recently perovskite solar cells. DSSCs based on nanocrystalline TiO2 as a photo-anode have attracted a lot of scientific and technological interest since their breakthrough in 1991 [1]. The two main functional aspects of charge generation and transport are no longer combined in one material but separated in different materials, i.e. a sensitizing dye, a wide-band-gap semiconductor (TiO2), and a liquid redox electrolyte [2].
关键词： photoanode,TiO2,dye-sensitized solar cells,electron transport,TiCl4 posttreatment,dye adsorption,photocurrent generation
更新于2025-09-12 10:27:22
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A new type of multibenzyloxy-wrapped porphyrin sensitizers for developing efficient dye-sensitized solar cells
摘要： Porphyrin dyes have been widely used for the fabrication of efficient dye-sensitized solar cells (DSSCs). However, dye aggregation and charge recombination still exert negative effects on photovoltaic performance, resulting in unsatisfactory power conversion efficiencies (PCE). Herein, we report a new class of porphyrin sensitizers XW52 and XW53 employing four benzyloxy groups to wrap the porphyrin cores. As a result, an efficiency of 7.6% was obtained for XW52, with Voc and Jsc of 668 mV and 16.63 mA cm-2, respectively. Compared with XW52, an additional 2,6-dialkoxyphenyl group has been introduced to the N-atom of the phenothiazine donor to furnish XW53 with the aim to further improve the anti-aggregation character and the solubility, and thus the Voc was improved to 674 mV, and a higher efficiency of 7.9% was achieved for XW53. Upon cosensitization with PT-C6, the Voc and Jsc were synergistically enhanced to 727 mV and 18.67 mA cm-2, respectively. As a result, a high efficiency of 9.6% was successfully achieved for the cosensitization system of XW53 + PT-C6. These results provide an effective novel strategy for designing efficient porphyrin dyes by introducing multiple benzyloxy groups to the meso-phenyl groups.
关键词： cosensitization,porphyrins,dye aggregation,dye-sensitized solar cells,wrapped structures
更新于2025-09-12 10:27:22
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[IEEE TENCON 2019 - 2019 IEEE Region 10 Conference (TENCON) - Kochi, India (2019.10.17-2019.10.20)] TENCON 2019 - 2019 IEEE Region 10 Conference (TENCON) - Investigation of “Keriang” fruit Dye application on the performance of Dye-Sensitized solar cell with anatase-rutile TiO <sub/>2</sub> Electrode
摘要： Dye-sensitized solar cell (DSSC) or ‘Gratzel cell’ is a low-cost solar cell from the thin film family which consists of TiO2 electrode coating, sensitizer from dye molecules soaked in the TiO2 film, a mediator electrolyte layer, and a counter electrode. This paper focuses on fabricating dye-sensitized solar cell (DSSC) with anatase and anatase-rutile mixture of nanocrystalline TiO2 at varied thickness sensitized with high light-absorbing nature dye and an alternative conductive counter electrode catalytic material. This paper proposes on the potentials of 10 μm thickness of rutile-anatase (RA) with a 1:4 ratio concentration, absorbed into a high concentration anthocyanin from ‘keriang’ fruit extract and by the use of carbon as a counter electrode. This arrangement shows the highest solar cell efficiency at 1.16% with higher short circuit current of 5.5 mA/cm2 and fill factor of 0.55 which is the highest among overall experimented nature-based solar cell.
关键词： Keriang,Rutile,Anatase,TiO2,Dye,DSSC,Dye-Sensitized solar cell
更新于2025-09-12 10:27:22
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π-Extended <i>cis</i> -Configured Unsymmetrical Squaraine Dyes for Dye-sensitized Solar Cells: Panchromatic Response
摘要： Light absorbing sensitizer is the heart of the third generation photovoltaic technologies such as dye-sensitized solar cells (DSSC). Despite possessing large extinction coefficients for the metal free organic dyes, the light harvesting efficiency is limited with the narrow absorption profile in either visible or NIR regions of the solar spectrum. Though monolayer formation of organic sensitizers on semiconducting metal oxide surface leads to dye-dye interaction that leads to broadening the absorption profile, the contribution of aggregated state to the power conversion process is found out to be poor. Here we have engineered far red active π-extended cis-configured unsymmetrical squaraine dyes with carboxylic acid and cycnoacetic acid as anchoring groups with controlled aggregation and panchromatic light absorption by including the steric and electronic factors. The presence of sp3-C (out of plane) and N-alkyl (in plane) groups played an important role in modulating the assembly the dyes on the TiO2 electrode, cis-squaraine unit helps to extend the conjugation in the NIR region besides enhancing the visible transition and the incident photon-to-current conversion efficiency (IPCE) profile showed the importance of anchoring groups for the panchromatic response. Dye PSQ10 showed solar-to-electric conversion with an onset of 850 nm with the device performance of 7.0% (Voc = 0.581 V, Jsc = 17.06 mA/cm2, FF = 70 %).
关键词： cis-Squaraine dyes,panchromatic response,dye-sensitized solar cells,extended far-red absorption,dye aggregation
更新于2025-09-12 10:27:22
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Highly Crystallized C-Doped Nickel Oxide Nanoparticles for p-Type Dye-Sensitized Solar Cells with Record Open-Circuit Voltage Breaking 0.5 V
摘要： In this work, unique carbon-doped NiO nanostructure (denoted as C/NiO) was synthesized via a facile precipitation/reduction reaction, followed by a subsequent oxidation process. The successful introduction of carbon in NiO gave rise to multiple tailing of the physical and electronic characteristics, including morphology, crystallinity, and conductivity, and valence band edge position. The carbon-doped NiO-fabricated dye sensitized solar cells actively generated an unrivalled VOC of 0.50 V and also a significantly increased short-circuit current densities (JSC, 0.202 mA cm-2), leading to an overall efficiency of 0.053%. The improved of photovoltaic performance could be mainly attributed to the significantly enhanced charge transport property and regarded charge recombination occurred at the NiO/electrolyte interface. This work provides an extremely simple and effective strategy for incorporating nonmetal elements in semiconductor oxides with remarkably improved photovoltaic performance.
关键词： charge transport,carbon-doped NiO,dye-sensitized solar cells,photovoltaic performance,valence band edge
更新于2025-09-12 10:27:22
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Synthesis of Anatase (Core)/Rutile (Shell) Nanostructured TiO <sub/>2</sub> Thin Films by Magnetron Sputtering Methods for Dye-Sensitized Solar Cell Applications
摘要： Currently, anatase/rutile core/shell structures are accepted as highly efficient building blocks for TiO2-based catalysts or photo-electrodes used in dye-sensitized solar cells (DSSCs). It is understood that a thin layer of rutile covering the core anatase pillar would improve the performance of DSSCs by retarding the charge recombination at the semiconductor/sensitizer/electrolyte interfaces. In this work, we report on the synthesis of core/shell nanostructured TiO2 thin films using reactive magnetron sputtering at a glancing angle with different power applying modes: well-separated pillars of pure anatase were synthesized using the DC mode, and then, high-pulse peak power was applied to the Ti target (high power impulse magnetron sputtering – HiPIMS) resulting in the covering of the anatase columns with a thin layer of rutile. The latter technique is well-known to increase the energy load during the growth of the film which is a key parameter to successfully obtain the TiO2 phase normally only achieved at high temperature, i.e. rutile. The peak current, the frequency and the pulse width were optimized in order to obtain the desired crystalline structure and thickness of the rutile top layer. Scanning Electron Microscopy (SEM) cross-section views of the synthesized films clearly show that the pillar-like structures are not affected by the energetic species striking the surface during the HiPIMS process. Grazing Incidence X-Ray Diffraction (GIXRD) suggests the presence of both anatase and rutile phases in the films. Further characterization of the anatase/rutile core/shell interface by electron transmission techniques such as Transmission Electron Microscopy (TEM) and Electron Energy Loss Spectroscopy (EELS) mapping confirm the hypothesis and reveal that the anatase pillars are partly covered by a rutile crust.
关键词： EELS,Dye-Sensitized Solar Cells,TEM,TiO2,GLAD,Reactive Magnetron Sputtering,core/shell nanostructures,HiPIMS
更新于2025-09-12 10:27:22
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The effect of bis-carboxylic groups of squarylium dyes on the efficiency of dye-sensitized solar cells
摘要： Symmetric squarylium dye (SQIND1) with bi-carboxylic groups has been synthesized and photoelectrochemical properties have been studied in comparison with its non-functionalized analog groups (SQIND2). The experimental results showed that the introduction of anchor carboxylic groups in SQIND1 sensitizer provides a more intimate contact with nanoparticles TiO2 which increases the number of charge carriers transferred from the SQIND1 to the semiconductor. The theoretical calculations and absorbance results show that the electron density of LUMO of SQIND1 is delocalized in the whole chromophore, leading to strong electronic coupling between SQIND1 sensitizer and conducting band of TiO2, resulting in improved dye-sensitized solar cell efficiency compared to SQIND2. Hence, the SQIND1 sensitized exhibit better photovoltaic performance. Although, the absence of any linker groups in the SQIND1, then SQIND1 was perfect efficiently sensitized on porous TiO2 with the long UV–Vis and NIR region up to 800?nm of the spectrum and showed higher remarkable performance of values, such as η of 3.3%, a Jsc of 7.6?mA/cm2, a Voc of 0.59, and FF of 0.73.
关键词： Cyclic voltammetry,Dye-sensitized solar cell,Symmetric squarylium dyes,Photoelectrochemical properties,DFT
更新于2025-09-12 10:27:22
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Surface Carbon Shell-Functionalized ZrO2 as Nanofiller in Polymer Gel Electrolyte-Based Dye-Sensitized Solar Cells
摘要： We prepare dye-sensitized solar cells (DSSCs) fabricated with a poly (ethylene glycol) based polymer gel electrolytes (PGEs) incorporating surface carbon shell-functionalized ZrO2 nanoparticles (ZrO2-C) as nano?llers (NFs). ZrO2 are polymerized via atom transfer radical polymerization (ATRP) using poly (ethylene glycol) methyl ether methacrylate (POEM) as a sca?old to prepare the ZrO2-C through carbonization. The power conversion e?ciency of DSSC with 12 wt% ZrO2-C/PGEs is 5.6%, exceeding that with PGEs (4.4%). The enhanced e?ciency is attributed to Lewis acid-base interactions of ZrO2-C and poly (ethylene glycol), catalytic e?ect of the carbon shells of ZrO2-C, which results in reduced crystallinity, enhanced ion conductivity of electrolytes, decreased counterelectrode/electrolyte interfacial resistance, and improved charge transfer rate. These results demonstrate that ZrO2-C introduction to PGEs e?ectively improves the performance of DSSCs.
关键词： polymer gel electrolyte (PGE),zirconium dioxide (ZrO2),dye-sensitized solar cell (DSSC),nano?ller (NF),carbon,atom transfer radical polymerization (ATRP)
更新于2025-09-12 10:27:22