Stability Of Dye-sensitized Solar Cells Research Articles

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.

Facile Fabrication of an SnSx‐SnO2‐Decorated Cobalt Sulfide Film as an Effective Counter Electrode for Dye‐Sensitized Solar Cells

AbstractMetal sulfide stands out as one of the novel and promising platinum‐free counter electrode (CE) materials for dye‐sensitized solar cells (DSSCs). In this work, SnSx‐SnO2‐decorated CoSx films were designed and synthesized by a low‐temperature fabrication process. The small clusters of nanoparticles create a large amount of catalytic active sites, resulting in superior electrocatalytic activity for triiodide reduction. The DSSC with SnSx‐SnO2‐decorated CoSx film has achieved an impressive power conversion efficiency of 4.57 %, which is close to the efficiency of the DSSC with platinum CE (4.82 %). Furthermore, regarding the attenuation of the photovoltaic performance for the DSSC with SnSx‐SnO2‐decorated CoSx film, negligible change was observed after a prolonged storage under ambient condition for five days. Therefore, it is worthwhile to expect the explorations of novel fabricate technique for synthesizing cost‐effective metal sulfide films with long‐term stability in DSSCs.

Improved efficiency and stability of dye-sensitized solar cells by using iodide-based electrolyte with high viscosity solvent

Dye-sensitized solar cell (DSSC) performance with a liquid electrolyte depends strongly on the choice of electrolyte solvent. Acetonitrile (AN) is the most widely used organic solvent due to its low viscosity and good solubility to dissolve iodide salts. However, the stability has become critical due to the high vapor pressure of AN. In this study, the efficiency and stability of DSSC using iodide-based electrolyte were observed by using high viscosity solvents namely dimethylformamide (DMF) and γ-butyrolactone (GBL). The cell using DMF shows the best performance with an efficiency of 7.69 %, higher than that of the cell with commercial AN-based electrolyte with an efficiency of 7.14 %. Impedance spectroscopy measurement to the cell using DMF reveals a relatively low charge transfer resistance, both at TiO2-dye/electrolyte and counter electrode/electrolyte interfaces, compared to other solvents. Furthermore, the efficiency is retained at 76 % after 4 weeks of storage under ambient air, the best among various solvents tested in the present study.

Milling Processing, Morphology, and Optical Characterization of Powders from Natural Pigments as a Potential Sensitizing Material for Optical Sensors and Dye-Sensitized Solar Cells

Dye-Sensitized Solar Cells (DSSC) and optical fiber-based-sensors sensitized with organic dyes play a fundamental role in modern technology, particularly in the family of photovoltaic power generation devices and measurement of chemical variables. DSSC is low-cost, highly efficient, and easy to manufacture. Therefore, they are a suitable option for many engineering applications. This paper deals with natural pigment extraction (spirulina, carrots (beta-carotene), and beetroot) at different milling and temperature conditions. Nanoparticles were fabricated using an SPEX mill and a planetary ball mill. The particle size distribution, absorbance (UV-Vis), and powder morphology were obtained using Field Emission Scanning Electron Microscopy (FESEM). Herein, the optical characterization of modified TiO2 powder at different temperatures and milling conditions is performed. Results indicate that each natural dye is sensitive to operational temperature. In addition, the absorbance of the pigments is affected by milling conditions and particle size distribution. During SEM characterization, rounded particles were observed in the starting materials with average sizes of more than 15 microns in diameter until they were reduced to nanometer ranges close to 100 using SPEX milling. The observed absorption spectra range from 400nm to 642 nm for spirulina. Moreover, the experimental results show that the intensity of the absorption peaks is affected by the temperature, which indicates a degradation of the dye. Therefore, different combinations of natural dyes will be feasible to improve the wide range of light absorption of the visible spectra and stability of DSSCs and optical fiber-based sensors.

Towards the thermal stability of dye-sensitized solar cells for wavelength-selective greenhouses using the polymorphism of light-scattering layers

Long-term thermal stability of DSSC was firstly highlighted by exploring the photoanode polymorphism.

A Review on the Applicability of Luminescent Phosphors and Effective Positioning in Dye‐Sensitized Solar Cells for Enhanced Performance and Stability

The narrow range of solar light absorption facilitated by the photoactive organic dyes has been restricting the significant development, and large‐scale applications of dye‐sensitized solar cells (DSSC). The major problem that limits the power conversion efficiency (PCE) of DSSC is the limitations of the organic dyes (light absorbers in DSSC) to absorb beyond the visible region of solar spectrum that resulting in lower PCE (≈13%) as compared with the commercialized technologies. Hence, the focus on developing efficient strategies to harvest the ultraviolet and infrared light regions of the solar spectrum and effective conversion into the absorption limit of dyes and thereby increasing the device performance and stability is the emerging technological development in DSSCs. Rare earth ion‐doped upconversion (UC) and downconversion (DC) phosphors are the most promising solutions for the prevalent issues of the liquid junction solar cells. This review will focus on the emerging strategies for the PCE enhancement of DSSC with UC and DC materials. An exclusive review on the facile approach of simultaneous usage of both the UC and DC phosphors and the effective positioning of these spectral conversion phosphors, to achieve highly stable DSSCs with superior PCE is provided.

Synergistic Effect of Size-Tailored Structural Engineering and Postinterface Modification for Highly Efficient and Stable Dye-Sensitized Solar Cells.

Despite significant progress in device performance, dye-sensitized solar cells (DSSCs) continue to fall short of their theoretical potential. Moreover, research in recent years needs to pay more attention to improving the device fabrication process. To achieve the theoretical efficiency limit, it is crucial to optimize the interface between the dye and TiO2 nanoparticles in the entire device stack. Our study indicates that optimizing the structure or size of the coadsorbents and implementing a monolayer adsorption process can be an effective strategy to reduce charge recombination and enhance light-harvesting properties. Our research aims to develop a surface-coating adsorbent plan that controls the TiO2 nanoparticle interface to achieve the radiative limit of power conversion efficiency (PCE). Specifically, we utilized 2-thiophenecarboxylic acid (THCA) or chenodeoxycholic acid (CDCA) as postinterfacial surface-coating adsorbents. Our results demonstrate that this approach effectively achieves the desired PCE limit. Combined with the coadsorbent structure engineering and interface optimization, the device increased the packing area on the TiO2 nanoparticles' surface, reaching an improved PCE of over 13.17% under simulated sunlight (1.5G), which is the highest efficiency of a porphyrin single dye-based DSSC. In particular, this practical approach was also applied to a large-area DSSC with an area of 3 cm2, yielding a remarkable PCE of 9.04%. Furthermore, when applied to a polymer gel electrolyte, this novel approach recorded the highest PCE of 11.16% with a long-term operational stability of up to 1000 h for the quasi-solid-state DSSCs. Our research findings provide a promising avenue for achieving high-performance DSSCs with ease of access and demonstrate practical applications as alternatives to conventional power sources.

A combination of fluorine-induced effect and co-sensitization for highly efficient and stable dye-sensitized solar cells.

Developing dyes with high open-circuit photovoltage (Voc) is a vital strategy to improve the power conversion efficiency (PCE) of co-sensitized solar cells (co-DSSCs). Herein, three organic fluorine-containing dyes [YY-ThP(3F), YY-ThP(2F), and YY-ThP(26F)] are designed and synthesized for investigating the fluorine-induced effect on photophysical and photovoltaic performances. Consequently, this effect can significantly broaden the UV-vis absorption spectra of dyes but fail to improve the light-harvesting capability of DSSCs. Strikingly, YY-ThP(3F), featuring 3-position fluorine substitution to cyanoacrylic acid, yields a relatively high Voc compared to the corresponding fluorine-free dye (YY-ThP). Furthermore, the co-sensitization of YY-ThP+YY-ThP(3F) achieves a remarkably high PCE and long-term stability. This work implies that the combination of judicious molecular engineering and co-sensitization is a promising strategy for highly efficient and stable DSSCs.

Urea and acetamide as alternative electrolyte additives for efficient and stable dye-sensitized solar cells

Urea and acetamide as alternative electrolyte additives for efficient and stable dye-sensitized solar cells

Studies on the performance and stability of dye-sensitized solar cells based on the co-sensitization of N719 and RK1 dye-sensitizers

The intention of this research is to demonstrate how the co-sensitization of organic and inorganic dyes influences the overall performance of the proposed method for DSSCs at low light intensities and enhances the power conversion efficiency of dye-sensitized solar cells (DSSCs). A maximum efficiency of 6.21% at 108 W/m2 was achieved by the co-sensitization method-fabricated DSSC. The co-sensitized photovoltaic cells work together synergistically to minimize the rate of electron and hole recombination, which leads to an increase in efficiency. The ruthenium-based N719 dye and the organic sensitizer RK1 are used in this co-sensitization approach because both dye-sensitizers have a significant impact on the performance of the DSSC. The proposed solar cells were analyzed using their current-voltage (I-V), incident photon-to-electron conversion efficiency (IPCE), and various DSSC parameters vs time properties. The proposed device has also retained 93.29% of its initial performance even after 1000 h.

Synergistic co-sensitization of environment-friendly chlorophyll and anthocyanin-based natural dye-sensitized solar cells: An effective approach towards enhanced efficiency and stability

This study reports on the preparation of TiO2 nanorods (TNRs) and their application in dye-sensitized solar cells (DSSCs) to enable the production of efficient sources of energy for use in ambient indoor circumstances. The aim of the study is to enhance the efficiency and stability of DSSCs while also making them more affordable and eco-friendly. To achieve this, a novel approach was taken through the synergistic co-sensitization of environment-friendly natural dyes based on Spinacia Oleracea Leaves (SOL: chlorophyll) and Ixora Coccinea Flowers (ICF: anthocyanin). The combination of these dyes improved light absorption and charge separation, leading to enhanced power conversion efficiency. Various physicochemical characterizations of TNRs and dyes were performed and the co-sensitized dyes exhibited greatly enhanced visible-light photo-electrochemical performance which were later evaluated by J-V and electrochemical impedance spectroscopy (EIS) studies. Additionally, the role of various economical and environment-friendly counter electrodes was investigated. Using this co-sensitization technique, FTO/c-TiO2/TNRs/dyes/electrolyte/(C, Ninp, Nip) structured DSSCs were designed for the production of power under ambient light conditions. The optimal PCE of 2.39% is achieved under the artificial irradiation of ∼ 996 Wm−2 which is 2.3 and 4.2- times greater efficiency compared to single natural SOL and ICF-dyes-based DSSCs, respectively. Moreover, the synergistically co-sensitized DSSCs showed improved stability under prolonged light soaking (∼450 h) and storage conditions (at 27 °C). This study highlights the potential of PV technologies in enabling buildings and movable gadgets to become more independent and smarter while also providing an efficient source of energy for use in ambient indoor circumstances.

Potential of transition metal sulfides, Cu2ZnSnS4 as inorganic absorbing layers in dye-sensitized solar cells

Organic dye sets a benchmark for dye-sensitized solar cells (DSSCs) application. Replacing the organic dyes with inorganic phases poses a significant challenge. Without organic dyes, efficiency decreases dramatically due to loss of charge transfer. Thus, surface modification techniques are widely considered to be the key to reducing the electron recombination, suppressing the dark currents and increasing efficiency of DSSC. Using multiple absorbent materials with different energy gaps/band gap values could broaden the DSSC's photon absorption range. This study investigated the potential applications of transition metal sulfides (TMS), kesterite (Cu2ZnSnS4, CZTS) as a promising inorganic absorber layer of DSSCs. Based on the current-voltage measurement, a lower molar ratio of milled CZTS compared to the N719-dye produced a stable DSSC with a power conversion efficiency (η), short-circuit current density (Jsc), and open-circuit voltage (Voc) of 4.75%, 13.99 mA cm−2, and 0.75 V, respectively. Furthermore, incident photon-to-current efficiency (IPCE) analysis exhibited an improved number of incident photons harvested by standard DSSC from 60% to 85% with and without the presence of CZTS. Even when light harvesting reached up to 80%, a higher concentration of CZTS content compared to the N719 dye produced an unstable solar cell device with a low Jsc and η due to electron loss through the recombination process. This was confirmed by the recombination resistance (Rrec) determined by the impedance spectroscopy (EIS), which found that the suppression of the Rrec at a lower ratio concentration between CZTS/N719-dye generated the highest η. The results that the use of the closest concentration of inorganic and organic co-sensitizers can improve the stability and overall performance of the developed DSSC. This approach has been regarded as the most sustainable economically viable means of producing cheap solar cells to convert the largest amount of energy from the solar spectrum to electricity.

2D-Nanolayer (2D-NL)-Based Hybrid Materials: A Next-Generation Material for Dye-Sensitized Solar Cells

Two-dimensional (2D) materials, an electrifying family of innovative materials, have recently attracted wide attention due to their remarkable characteristics, primarily their high optical transparency, exceptional metallic conductivity, high mechanical strength, carrier mobility, tunable band gap values, and optimum work function. Interestingly, 2D-nanosheets/nanolayers (2D-NLs) might be synthesized into single/multi-layers using simple processes such as chemical vapor deposition (CVD), chemical bath deposition (CBD), and mechanical and liquid-phase exfoliation processes that simply enhance optoelectronic properties. However, the stability of 2D-NLs is one of the most significant challenges that limits their commercialization. Researchers have been focusing on the stability of 2D-NLs with the aim of developing next-generation solar cells. Easily tunable distinctive 2D-NLs that are based on the synthesis process, surface functional groups, and modification with other materials/hybrid materials thereby improve the stability of the 2D-NLs and their applicability to the hole transport layer (HTL) and the electron transport layer (ETL) in solar cells. Moreover, metal/non-metal-based dopants significantly enhance band gap ability and subsequently improve the efficacy of dye-sensitized solar cells (DSSCs). In this context, research has focused on 2D-NL-based photoanodes and working electrodes that improve the photoconversion efficiency (PCE) and stability of DSSCs. Herein, we mainly focus on synthesizing 2D-NLs, challenges during synthesis, stability, and high-performing DSSCs.

Investigation on optical properties and photovoltaic performance of solid-state dye-sensitized solar cells comprised of photoanodes of titanium dioxide nanoparticles calcinated at different temperatures

Dye-sensitized solar cells (DSSCs) were constructed using photoanodes of TiO2 nanoparticles (Degussa P25) calcinated at diverse temperatures. The calcinated TiO2 nanoparticles were characterized by X-ray diffraction (XRD) technique and N719 dye anchored TiO2 thin films were subjected to diffuse reflectance spectral and dye desorption studies. The band gaps of TiO2 nanoparticles calcinated at higher temperatures (700 and 900 °C) were shifted to lower energy levels by predominant anatase phase transformation into rutile and increase in the particles size. The performance of DSSCs with TiO2 (Degussa P25) nanofiller incorporated solid-state PEO electrolyte was examined at light intensity of 60 mW cm−2. The DSSC with TiO2 (Degussa P25) nanoparticles photoanode was exhibited overall efficiency of 1.86%, which was ∼4.9 and 9.8-folds greater over the DSSCs having photoanodes of TiO2 nanoparticles calcinated at 700 and 900 °C, respectively. This can be attributed to higher surface area of TiO2 nanoparticles that facilitates higher dye adsorption and predominant anatase phase for favorable electron transfer. The DSSCs stability was confirmed through chronoamperometry experiments.

Synthesis of titanium dioxide/reduced graphene oxide nanocomposite by ultrasound-assisted mechanical mixing method for fabricating photoanode to upgrade the performance and stability of dye-sensitized solar cell

• TiO 2 /rGO was successfully synthesized by ultrasound-asissted mechanical mixing method. • 1.0 wt.% rGO under 720-W ultrasonic power was optimal synthesis conditions. • The presence of rGO enhanced and stabilized DSSC performance. • Nano-sized TiO 2 paticles were evenly anchored on rGO sheets. • rGO could enhance the thermostability and photostability of the DSSC. Herein, titanium dioxide/reduced graphene oxide (TiO 2 /rGO – TG) nanocomposite was synthesized via the ultrasound-assisted mechanical mixing method, used for the fabrication of photoanode in dye-sensitized solar cells (DSSCs). The DSSCs performance was evaluated by current density-voltage (J-V) curves and electrochemical impedance spectroscopy (EIS), showing that the sample with 1.0 wt.% rGO under the ultrasonic power of 720 W, was an optimal material for fabricating photoanode in DSSCs, which obtained the power conversion efficiency of 6.37 %. Additionally, in the 500-hour illumination test under 300-watt metal-halide lamp and the 100-hour drying at 85 °C, DSSCs with the presence of rGO proved better stability in comparison with DSSCs fabricated from commercial TiO 2 . The characterization of TG was analyzed by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy, indicating that TiO 2 nanoparticles are uniformly distributed onto the rGO sheets with the average diameter from 20 to 70 nm.

Synthesis of polymer-gel electrolytes for quasi solid-state dye-sensitized solar cells and Modules: A potential photovoltaic technology for powering internet of things (IoTs) applications

Dye-sensitized solar cells can display brilliant performance in artificial/indoor light, predominantly in various wireless sensor networks applications. The main objective of this work was to fabricate stable dye-sensitized solar cells/modules for the internet of things applications. The stability issue was addressed by developing polymer gel electrolytes. Polymer gel electrolyte with the highest ionic conductivity value was then employed as an electron transport mediator in the cells and modules. The photovoltaic performance of cells was affected by the conductivity of electrolytes. The results showed that the efficiency of quasi-solid state dye-sensitized solar cells remained stable for a week, while the efficiency of conventional cells approached zero after a day. Thus, the development of polymer gel electrolytes is an ultimate solution to enhance the stability of dye-sensitized solar cells and modules for the internet of things applications.

Computational molecular design of NIR dyes with varying anchoring groups for improving the efficiency and stability of dye-sensitized solar cells

Design and development of near-infrared (NIR) dyes with strong binding on the TiO2 surface is inevitable for the realization of the dye-sensitized solar cells (DSSCs) with improved efficiency and stability. A series of NIR dyes bearing different anchoring groups have been designed considering their suitability as sensitizers for DSSCs based-on TiO2 and iodine-based redox electrolytes. Under the Gaussian program, density functional theory (DFT)/6-311G/B3PW91 level of theory and time-dependent-DFT using the polarizable continuum model is shown optimum for the prediction of the highest occupied molecular orbital energy level and electronic absorption spectra. The reliability of the calculated results was validated by corresponding experimental results for some of the representative dyes. It has been demonstrated that λ max at full width at half maximum in calculated absorption spectra exhibited an excellent match with the experimentally estimated Eg of the sensitizers leading to the proposal of a new method for the construction of the theoretical energy band diagram. Amongst newly designed sensitizers, dyes bearing dual anchoring groups like SQ-149, SQ-150, SQ-158, SQ-161 and SQ-162 are highly promising not only for good NIR photon harvesting but also to impart to improved DSSC stability.

Holistically modulating charge recombination via trisiloxane surface treatment for efficient dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) with TiO2 as electron transport layer (ETL) demonstrate great potential in the field of photoelectric devices featuring low cost and high power conversion efficiency (PCE). However, the photovoltaic performance of DSSCs based on TiO2 ETL is still confined by the undesirable charge recombination occurring in TiO2 layer (intrinsic defects), dye layer (self-quenching) and at the interface between TiO2 and electrolyte (back electron transfer). Herein, we firstly adopted a trisiloxane molecule (denoted as TSi) to holistically reduce the abovementioned charge recombination of DSSCs via passivating surface defects of TiO2, fine-tuning dye molecules arrangement and forming interfacial energy barrier. As a result, the Z907-based DSSCs with TiO2/TSi ETL deliver a high PCE of 9.43%, increasing over 16% than that of DSSCs without TSi treatment. Meanwhile, the DSSCs based on TiO2/TSi ETL present stronger endurance to high humidity and better long-term stability versus that of the DSSCs without TSi treatment. Our work provides a simple yet effective strategy to holistically reduce charge recombination of devices for improving the photovoltaic performance and stability of DSSCs.

Effect of Extending the Conjugation of Dye Molecules on the Efficiency and Stability of Dye-Sensitized Solar Cells.

We designed and synthesized two organic dyes (A6 and A10) for dye-sensitized solar cells (DSSCs) by extending the molecular conjugation strategy. The sensitizer A10 was constructed by inserting ethene into our previously reported sensitizer AZ6. The sensitizer A6 was obtained by further substituting the hydrogen of ethene with another donor (D) and π-bridge-acceptor (π–A) segment. The UV–vis spectra and J–V curves showed that the dyes A10 and A6 could effectively facilitate the light-harvesting and photocurrent densities with respect to AZ6. Consequently, the A10-based DSSC achieved an enhanced efficiency (8.54%) with a high photocurrent (18.81 mA cm–2). Desorption experiments of dyes adsorbed on TiO2 showed that compared with the monoanchoring dyes AZ6 and A10, the dianchoring configuration effectively strengthened the affinity of dye A6 with the photoanode, making it more difficult to leach from the photoanode. The A6-based DSSC shows outstanding stability, and its overall efficiency could remain 98.0% of its initial value after 3000 h of aging time, exceeding that of its monoanalogue AZ6 (remained 78.3% after 3000 h).

Increased efficiency and stability of Dye-Sensitized Solar Cells (DSSC) photoanode by intercalation of Eosin Y into Zn/Al layered double hydroxide

Layered Double Hydroxides (LDH) are versatile materials that can be applied to different fields. Recently their employment in Dye-Sensitized Solar Cells (DSSCs) technology has been reported. The heart of this technology is the photoanode, a semiconductor layer sensitized with dye molecules able to absorb the sunlight. However, the traditional dye molecules are quite expensive and sensitive to thermal degradation and the sensitization process requires time and costs. The possibility to directly intercalate the dye in the LDH interlayer makes these materials very promising as innovative photoanodes. This aspect in fact would help to reduce both the time and the costs, overcome charge-transfer and recombination phenomena issues and finally increase the Photo-Conversion Efficiency (PCE) and stability. In this work, an Eosin Y-intercalated ZnAl LDH was prepared by coprecipitation and applied as photoanode material. For this purpose, a screen-printing ink was formulated and then applied onto a conductive transparent substrate. Then, complete DSSC prototypes were assembled and tested. A comparison with an analogous LDH intercalated with terephthalate and sensitized with Eosin Y showed a beneficial effect due to the presence of the dye intercalated in the structure rather than adsorbed on the surface, increasing the stability (tested for 1500 h) and efficiency of the related DSSCs. A 0.11 mA cm−2 of JSC, 568 mV of VOC and a PCE of 0.019% were obtained for the Eosin Y intercalated LDH based photoanode. Moreover, the interaction between the intercalated dye and the LDH sheets allowed to reduce charge recombination phenomena and thus to increase VOC and PCE values.