Flexible Dye-sensitized Solar Cells Research Articles

Design and Preparation of Bending-Resistant Flexible All-Solid Dye-Sensitized Solar Cells

Design and Preparation of Bending-Resistant Flexible All-Solid Dye-Sensitized Solar Cells

A very simple flexible tandem dye-sensitized solar cell

AbstractDye-sensitized solar cells (DSSCs) have been proposed as the most important third generation photovoltaic devices owing to their low fabrication cost, design flexibility, having low hazard to the environment and ease of construction. Tandem DSSCs (T-DSSC) were said to possess properties of its sensitized photoanode and sensitized photocathode in terms of the power conversion efficiency (PCE) parameters. With less studies on the fabrication of simple a flexible tandem DSSC, this work aims at filling this gap as well as showing the influence of one of the main factors that affect the performance of such a device. In this paper, TiO2 and NiO layers were prepared by blading method, sensitized separately, then sandwiched together. The fabricated device produced short circuit current, open circuit voltage and power conversion efficiency of 0.138 mA.cm−2, 0.942 V and 0.063%, respectively. This simple T-DSSC produced a high photovoltage and showed that the photocurrent produced by each photoelectrode should be identical. This match is to overcome the possible hump in the device performance.

Performance of Flexible Dye-Sensitized Solar Cell (FDSSC) Using Flexible Substrate at Different Angles Under Back-Illumination Configurations

Performance of Flexible Dye-Sensitized Solar Cell (FDSSC) Using Flexible Substrate at Different Angles Under Back-Illumination Configurations

Efficient flexible dye-sensitized solar cells from rear illumination based on different morphologies of titanium dioxide photoanode

The TiO2 with nanoparticles (NPs), nanowires (NWs), nanorods (NRs) and nanotubes (NTs) structures were prepared by using a in-situ hydrothermal technique, and then proposed as a photoanode for flexible dye-sensitized solar cell (FDSSC). The influences of the morphology of TiO2 on the photovoltaic performances of FDSSCs were investigated. Under rear illumination of 100 mW·cm−2, the power conversion efficiencies of FDSSCs achieved 6.96%, 7.36%, 7.65%, and 7.83% with the TiO2 photoanodes of NPs, NWs, NRs, and NTs and PEDOT counter electrode. The FDSSCs based on TiO2 NRs and NTs photoanodes have higher short circuit current densities and power conversion efficiencies than that of the others. The enhanced power conversion efficiency is responsible for their nanotubes and rod-shaped ordered structures, which are more beneficial to transmission of electron and hole in semiconductor compared to the TiO2 nanoparticles and nanowires disordered structure.

TiO2-bismuth screen printing ink for flexible low temperature dye sensitized solar cells

Flexible dye sensitized solar cells (DSSCs) possess multiple advantages with wide application and good commercialisation potential. However, the low conversion efficiency of the technology from poor charge transfer and interparticle contact has limited their utilisation. Thus, the research aims to enhance the performance of flexible plastic-based titanium dioxide (TiO2) film via the formation of TiO2-bismuth (Bi) ink for screen-printing of DSSC photoanode film. The implementation of Bi nanoparticles as sintering aid has managed to improve the interparticle contact in the photoanode film with neck formation at the TiO2-Bi interface. This phenomenon has also led to the lowering of resistance values by 57 - 65% with charge transfer resistance of 11.72 kΩ.cm2 and series resistance of 38.28 kΩ.cm2 for the TiO2-Bi photoanode. The recombination reactions were also reduced with longer electron lifetime of 0.0036 ms and enhanced charge transfer. The research has managed to prepare TiO2-Bi ink that would be suitable for the fabrication of flexible DSSC photoanode film via screen printing. Hence, the outcome of the research could potentially lead to the development of highly efficient flexible low temperature DSSC and enhance their commercialisation potential.

Effect of lead sintering aid to TiO2 photoanode for flexible dye sensitized solar cell

The commercial application of flexible dye sensitized solar cells (DSSCs) is somewhat limited due to the devices’ low conversion efficiency. The low sintering temperature in preparing the photoanode has caused poor interparticle contact, low charge transfer and low efficiency. Hence, this research aims to improve the interparticle contact of titanium dioxide (TiO2) photoanode with the novel use of lead (Pb) nanoparticles as sintering aid at low temperature. TiO2-Pb composite photoanode was prepared with different composition of Pb including 4% and 7% sintered at low temperature of 250°C. The research discovered that TiO2 photoanode mixed with 4% Pb composition showed the lowest charge transfer resistance (RCT) even at low sintering temperature. The RCT value was even lower than a commercial TiO2 photoanode sample that was sintered at 450°C. The addition of Pb sintering aid has improved interparticle contact in the photoanode via the neck formation at the TiO2-Pb interface and enhanced charge transfer despite the low temperature. The prepared photoanode samples displayed potential in developing highly efficient flexible DSSC.

Incorporation of Bi sintering aid to TiO2 photoanode for low temperature dye sensitized solar cell

The low conversion efficiency for low temperature dye sensitized solar cells (DSSCs) due to poor interparticle contact and charge transfer of TiO2 photoanode has been an issue for the solar cell. Therefore, the research aims to combat the issue with the implementation of bismuth (Bi) nanoparticles as sintering aid to the TiO2 photoanode. The addition of Bi sintering aid was found to form necks at the TiO2-Bi matrix seen in the morphological studies, despite the low sintering temperature of 200°C, due to the low melting point of Bi (271.4°C). The formation of these necks improved the interparticle contact and charge transfer of the photoanode that was observed in the electron transfer studies. Photoanodes with Bi sintering aid yielded lower charge transfer resistance (RCT) and series resistance (RS) than bare TiO2 photoanode by 15%-31%. The RCT and RS of TiO2-4%Bi photoanode (RCT=7.244 kΩ/cm2, RS=14.64 kΩ/cm2) was even almost comparable to the commercially prepared TiO2 photoanode at high temperature of 450°C (RCT=5.125 kΩ/cm2, RS=10.34 kΩ/cm2). Thus, indicating the potential for this approach in enhancing the overall performance of flexible low temperature DSSC in the future.

Pouch-sealing as an effective way to fabricate flexible dye-sensitized solar cells and their integration with supercapacitors

The scientific interest in integrated energy harvesting and storage (HS) devices has increased exponentially in the last decade since they represent an optimal solution to power portable electronic devices and low consuming Internet of Thing (IoT) sensor nodes. The integration of energy storage devices with photovoltaics can allow to avoid problems such as continuous battery replacement and periodic maintenance, reducing overall costs. In this context, dye sensitized solar cells (DSSCs) integrated with a supercapacitor represent the best choice in terms of lifetime, charge-discharge efficiency, and simplicity of connection avoiding electrical signal conditioning between the two devices. DSSCs have many similarities with supercapacitors, with the only aspect that remains uncovered being the sealing of the device. Herein we propose a common vacuum sealing technology for the integration of a supercapacitor and a DSSC made with shared current collectors, to maximize the integration between the two technologies. The HS device showed a maximum overall photon to electrical conversion and storage efficiency (OPECSE) of 6.10% under only 0.1 SUN illumination, thanks to the high photoconversion efficiency showed by the pouch sealed DSSC, equal to 6.62%. The HS device showed a high stability under bending condition and repeated photo-charge/discharge cycling.

The development of Au-titania photoanode composites toward semiflexible dye-sensitized solar cells

Considering the widespread use of windows in modern urban landscapes, converting these substrates into photovoltaic devices would remarkably impact modern energy generation. A flexible dye-sensitized solar cell (DSSC) architecture is preferred for such applications. A key component of the DSSC is the dye-sensitized photoanode. Herein, we examine different nanoparticle composites within the semiconductor anode formulation and their effect on device performance. Mesoporous titania particles (TiO2) modified with Au-nanoparticles (TiO2@AuNPs) were synthesized using precipitation strategies to assess the solvent effect on the particle size and the efficiency of the devices. The materials were then fully characterized through SEM, XRD, and DRS before and after thermal treatment. A paste prepared from the synthesized semiconductors was applied onto the substrate using the doctor blading technique. The use of high thermal treatment for glass substrates (HTT), low-temperature thermal treatment (LTT), and LTT combined with 2 h of UV curing (LTT_UV) was explored. In the case of ITO/PET (flexible substrate) only low temperature thermal treatment were used (LTT and LTT_UV). After characterization (XRD and DRS), the anodes were loaded using a metal-free dye. To complete the comparison, several groups of cells were characterized: considering solvent (EtOH and EtOH:H2O), thermal treatment (HTT, LTT, and LTT_UV), and semiconductor material (TiO2 and TiO2@AuNP). Rigid (glass anode-glass cathode) and semiflexible (flexible anode-glass cathode) DSSCs were obtained with efficiencies from 0.03% to 2.4%, with a substantial performance difference seen using different thermal treatments, and a mild to low effect on semiconductor composition and the used substrate.

Low-Temperature Fabrication of Flexible Dye-Sensitized Solar Cells: Influence of Electrolyte Solution on Performance under Solar and Indoor Illumination

Flexible photovoltaics is an attractive technology for product-integrated energy supply under both outdoor and interior conditions. In particular, dye-sensitized solar cells (DSSCs) based on flexible plastic conductive substrates provide ample opportunities for unique applications; however, they prevent the use of high-temperature processing steps usually applied in the fabrication of the solar cell. In the first part of this paper, we present an overview of a careful selection of the most relevant work in the field of flexible DSSCs (F-DSSCs), ranging from pioneering methodsto the most cutting-edge techniques. Key elements and critical considerations for the design of an efficient F-DSSC are also provided. In the second part, we report the fabrication of DSSCs on both rigid and flexible plastic substrates using low-temperature processing. Three different I−/I3− electrolyte configurations were tested. Rigid and F-DSSC showed 2.62% and 1.00% efficiency under 1 sun and an output power of 8.60 and 4.00 μW/cm−2 under low-light conditions, respectively. In this work, we report a novel solvent mixture that shows a significant enhancement of the performance of the low-temperature processed configuration, without adding steps in the fabrication process.

Electrochemical and power conversion performance of different counter electrode materials for flexible dye-sensitized solar cells.

Carbon dots and copper indium sulfide are promising photovoltaic materials, which have so far been fabricated mainly by chemical deposition methods. In this work, carbon dots (CDs) and copper indium sulfide (CIS) were separately combined with poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) for the preparation of stable dispersions. These prepared dispersions were used to produce CIS-PEDOT:PSS and CDs-PEDOT:PSS films using the ultrasonic spray deposition (USD) approach; furthermore, platinum (Pt) electrodes were fabricated and tested for flexible dye sensitized solar cells (FDSSCs). All the fabricated electrodes were utilized as counter electrodes for FDSSCs, and the power conversion efficiency of the FDSSCs reached 4.84% after 100 mW cm-2 AM1.5 white light was used to excite the cells. More investigation reveals that the improvement might be caused by the CDs film's porosity network and its strong connection to the substrate. These factors increase the number of sites available for the effective catalysis of redox couples in the electrolyte and facilitate the movement of charge in the FDSSC. It was also emphasized that the CIS film in the FDSSC device helps to generate a photo-current. In the beginning, this work shows how the USD approach can create CIS-PEDOT:PSS and CDs-PEDOT:PSS films and confirms that a CD based counter electrode film produced using the USD method is an interesting replacement for the Pt CE in FDSSC devices, while the results obtained from CIS-PEDOT:PSS are also comparable with standard Pt CE in FDSSCs.

Increase the current density and reduce the defects of ZnO by modification of the band gap edges with Cu ions implantation for efficient, flexible dye-sensitized solar cells (FDSSCs)

Flexible dye-sensitized solar cells (FDSSCs) have good potential in future photovoltaic technology. The spin coating method deposited the ZnO films on indium-tin-oxide-coated polyethylene terephthalate (ITO-PET) flexible plastic substrates. These films are implanted with Cu-ions with 1 × 1013 ions/cm2, 1 × 1014 ions/cm2, and 1 × 1015 ions/cm2. All the films have a hexagonal structure. The film irradiated with 1 × 1014 ions/cm2 showed high crystallinity and crystallite size. Important optical properties like bandgap energy (Eg), band edges, refractive index, extinction coefficient, and dielectric constants are measured by UV–Vis spectroscopy. Bandgap energy decreases, and the refractive index increases at the fluence of Cu ions. The maximum decrease in Eg is observed at the 1 × 1014 ions/cm2 dose. Photoluminescence spectra suggest that defects-related emission peaks are decreased at 1 × 1014 ions/cm2 Cu ions fluency. J-V measurements have significantly improved photovoltaic performance compared to pristine ZnO-based solar cells. The highest efficiency (2.30%) is observed at a 1 × 1014 ions/cm2 dose. The efficiency increase is related to improving the charge transfer ratio and shifting the fermi level toward the conduction band.

Carbon nanomaterials staked with nonwoven (EG/PAN/CQDs) composite as a counter electrode for enhanced photons and photocatalytic efficiency

Prior studies on heavy metal heterojunction with carbon nanomaterials for dye-sensitized solar cells (D-SSCs) found that they were not only toxic but also had poor stability and led to a difficult synthesis. In this work, nanomaterials with flexible nonwoven sheets were employed to improve cell efficiency and were easily synthesized with high stability, durability, washability, and flexibility. By incorporating carbon quantum dots (CQDs) into the anode and counter electrodes, it is possible to boost photon efficiency by scattering the sunlight and turning a huge amount into current density. Here in this research, Textile carbon–based flexible dye-sensitized solar cells (TC-DSSC) with N-doped CQDs may significantly increase solar cell efficiency. Carbon-based nanoparticles stacked with textile apparel (nonwoven bamboo) sheets enabled the desired flexible end applications to be achieved. The prepared material significantly increased solar cell efficiency to 11.26% compared to 8.04% of the one without CQDs. Carbon-based nanomaterials are stacked with textile apparel (nonwoven bamboo) sheets to make them lightweight, highly flexible, wearable, and user-friendly. Furthermore, compared to pure expanded graphite on the nonwoven substrate, a single electrode incorporating CQDs offered low impedance and high current/voltage. On the other hand, when tested for photocatalytic activity using spectrophotometry, the proposed counter electrode made of expanded graphite, PAN, and CQDs loaded on nonwoven material completely degraded the methylene blue dye in a very short period of time. The N-CQDs may prove to be very stable with outstanding washing endurance anchored with expanded graphite layered on a nonwoven medium with an optimum thickness.

Fabrication of cellulose paper-based counter electrodes for flexible dye-sensitized solar cells.

Here, we introduce the synthesis and deposition of organic/inorganic composite ink on cellulose paper using a rapid ultrasonic spray deposition approach that can be incorporated as a counter electrode (CE) in flexible dye-sensitized solar cells (FDSSCs). The composite ink comprised a copper indium sulfide (CuInS2) nanostructure ink and dispersion of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) in water. Fabricated counter electrodes are biodegradable, environment-friendly, flexible, and economical and meet the requirements for sustainable green energy. To evaluate the catalytic activities and power conversion efficiencies of DSSCs, the produced CuInS2/PEDOT:PSS composite ink-based CEs were compared with PEDOT:PSS counter electrodes. Cyclic voltammetry studies found that CuInS2/PEDOT:PSS had a greater cathodic charge transfer current density (Jc) (-1.23 mA cm-2). Moreover, it was found that the potential separation values are small, which indicate a stronger catalytic activity than PEDOT:PSS counter electrodes. The observed exchange current density (J0) was 3.98 mA cm-2, while the limiting current density (Jlim) increased to 45.7 mA cm-2, indicating a fast redox diffusion rate of the CuInS2/PEDOT:PSS CE. The photovoltaic performances of CuInS2/PEDOT:PSS and PEDOT: PSS-based DSSC's were measured and determined to be 5.66% and 4.41%, respectively, while the performance of CuInS2/PEDOT:PSS FDSSC composed of cellulose paper was 1.06%.

Low-Temperature Chemical Sintered TiO2 Photoanodes Based on a Binary Liquid Mixture for Flexible Dye-Sensitized Solar Cells

A chemically sintered and binder-free paste of TiO2 nanoparticles (NPs) was prepared using a binary-liquid mixture of 1-octanol and CCl4. The 1:1 (v/v) complex of CCl4 and 1-octanol easily interacted chemically with the TiO2 NPs and induced the formation of a highly viscous paste. The as-prepared binary-liquid paste (<bold>P</bold>BL)-based TiO2 film exhibited the complete removal of the binary-liquid and residuals with the subsequent low-temperature sintering (~150°C) and UV-O3 treatment. This facilitated the fabrication of TiO2 photoanodes for flexible dye-sensitized solar cells (f-DSSCs). For comparison purposes, pure 1-octanol-based TiO2 paste (<bold>P</bold>O) with moderate viscosity was prepared. The <bold>P</bold>BL-based TiO2 film exhibited strong adhesion and high mechanical stability with the conducting oxide coated glass and plastic substrates compared to the <bold>P</bold>O-based film. The corresponding low-temperature sintered <bold>P</bold>BL-based f-DSSC showed a power conversion efficiency (PCE) of 3.5%, while it was 2.0% for <bold>P</bold>O-based f-DSSC. The <bold>P</bold>BL<bold>-</bold>based low- and high-temperature (500°C) sintered glass-based rigid DSSCs exhibited the PCE of 6.0 and 6.3%, respectively, while this value was 7.1% for a 500°C sintered rigid DSSC based on a commercial (or conventional) paste.

Flexible Nano-TiO2 Sheets Exhibiting Excellent Photocatalytic and Photovoltaic Properties by Controlled Silane Functionalization-Exploring the New Prospects of Wastewater Treatment and Flexible DSSCs.

TiO2 nanoparticles surface-modified with silane moieties, which can be directly coated on a flexible substrate without the requirement of any binder materials and postsintering processes, are synthesized and characterized using X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, Brunauer–Emmett–Teller, X-ray photoelectron spectroscopy, Raman spectroscopy, photoluminescence spectroscopy, time-correlated single-photon counting, and transmission electron microscopy. The viability of the prepared surface-modified TiO2 (M-TiO2) sheets as a catalyst for the photo-induced degradation of a model dye, methylene blue, was checked using UV–visible absorption spectroscopy. The data suggest that, compared to unmodified TiO2, M-TiO2 sheets facilitate better dye-degradation, which leads to a remarkable photocatalytic activity that results in more than 95% degradation of the dye in the first 10 min and more than 99% of the degradation in the first 50 min of the photocatalytic experiments. We also demonstrate that M-TiO2 can be recycled with negligible reduction in photocatalytic activity. Further, the photovoltaic properties of the developed M-TiO2 sheets were assessed using UV–visible absorption spectroscopy, electrochemical impedance spectroscopy (EIS), and photochronoamperometry. Dye-sensitized solar cells (DSSC) fabricated using M-TiO2 as the photoanode exhibited a photoconversion efficiency of 4.1% under direct sunlight. These experiments suggested that M-TiO2 sheets show enhanced photovoltaic properties compared to unmodified TiO2 sheets, and that, when N-719 dye is incorporated, the dye–TiO2 interaction is more favorable for M-TiO2 than bare TiO2. The simple solution processing method demonstrated in this paper rendered a highly flexible photoanode made of M-TiO2 with superior charge-separation efficiency to an electrode made of bare TiO2. We propose that our findings on the photovoltaic properties of M-TiO2 open up arenas of further improvement and a wide scope for the large-scale production of flexible DSSCs on plastic substrates at room temperature in a cost-effective way.

ELECTRICAL ANALYSIS OF SEMI-FLEXIBLE AND FLEXIBLE DSSCS: COMPARISON STUDY

In this study, semi-flexible dye-sensitized solar cell (DSSC) and flexible DSSC are examined comparatively. First, TiO2 paste with HCl was prepared and flexible photoanodes were produced by coating this paste on the indium tin oxide-coated poly(ethylene terephthalate) (ITO/PET) flexible substrates under the same conditions. These flexible photoanodes have been sensitized with Ruthenizer N719 dye at room temperature for 48[Formula: see text]h. The Pt was used as the back-electrode. The first back-electrode was fabricated for semi-flexible DSSC by spraying Pt on the fluorine-doped tin oxide (FTO). The second back-electrode was fabricated for flexible DSSC by coating Pt on ITO/PET using the chemical reduction method. The flexible photoanodes and Pt counter-electrodes have been combined. The photovoltaic performance of the semi-flexible DSSC was compared to the flexible DSSC.

Preparation of ZnO/NiO-loaded flexible cellulose nanofiber film electrodes and their application to dye-sensitized solar cells

Since flexible solar cells are demanded portable purposes, materials are requested to be light and soft. Hence the present work focused on the preparation of metal oxide-based flexible dye-sensitized solar cells (DSSCs) using sustainable, eco-friendly TEMPO-oxidized cellulose nanofiber (TOCNF) films as substrates and their performances were compared. When nanorod (NR), nanowire (NW), and nanoparticle (NP) of ZnO or NiO as photovoltaic materials and carbon dot (Cdot) and N719 dye as photosensitizers were used, the coating of ZnONP (50 wt%) incorporated Cdot on ZnONW/Cdot/TOCNF substrate revealed the better photovoltaic conversion efficiency (PCE) (1.34%) and the lower charge transfer resistance property. A NiONP/Cdot-coated NiONW/TOCNF electrode also achieved a good PCE, but the hydrophobic treatment of TOCNF improved the efficiency to be 1.45%. Although the flexible working electrodes for DSSCs were successfully manufactured from a biodegradable and sustainable TOCNF, more effort is still required at least to achieve the performance (4.43%) of conventional non-biodegradable polyethylene terephthalate substrate.

Numerical modelling and simulation of heat sink assisted thermal sintering of titania film on polymer substrates for the fabrication of high-performance flexible dye sensitized solar cells

In this paper, we report a mathematical model developed to study thermal characteristics of heat sink assisted elevated temperature sintering of TiO2 coated polymer photoelectrode used for the fabrication of high-performance flexible dye sensitized solar cells (FDSSCs). Thermal sintering of TiO2 film deposited indium tin oxide coated polyethylene terephthalate (ITO PET) is usually restricted by the polymer serviceability temperature limit (~ 150 °C), but the heat sink assisted sintering process increases sintering temperature without affecting the polymer integrity, produces effectively sintered TiO2 film on the polymer surface and boosts the photovoltaic performance of FDSSCs. The developed model involves simultaneous heat transfer and coolant flow within the system which is dynamically coupled with an external coolant reservoir. Using this model, effects of various parameters such as coolant flow rate, heat sink material, heat sink geometry, and sintering duration on the thermal characteristics of TiO2 sintered on polymer substrate are studied. Also, the FDSSCs fabricated using this sintering method have shown power conversion efficiency increased significantly because of the rise in sintering temperature is controlled by the heat sink thermal parameters. Besides, possibilities of scaling-up of this sintering system for the fabrication of large area FDSSCs are investigated.

Current advancement of flexible dye sensitized solar cell: A review

In the last two decades, research on dye-sensitized solar cells (DSSCs) has shown tremendous improvement with promising findings. It has become one of the alternative options in replacing conventional silicon-based photovoltaics. Recently, a study towards the flexible form of solar cells has gained the attention of researchers. The features possess in DSSC such as high flexibility, light weight and environmentally friendly have made DSSC suitable for such purposes compared to rigid glass substrates. However, the biggest challenge faced by plastic-type substrates is temperature, where plastic substrates only withstand up to 150 °C before melting. In the DSSC fabrication process, temperatures as high as 400–500 °C are critically required for the purpose of material crystallization. With insufficient temperature during this process, poor interconnection between nanoparticles and increased electrode resistance will occur, thereby lowering the performance of plastic based DSSC. Here, we discuss the approaches that researchers have performed in solving the problem. Such approaches include the use of doctor blades, electrophoretic deposition, hydrothermal, peel and stick technique, and pulse laser deposition methods. In addition, this paper also discusses the most recent method which is additional procedure using Titanium(IV) tetraisopropoxide or UV-O3 treatment in the preparation of flexible DSSC. Several types of photoanode materials such as titanium dioxide, zinc oxide and graphene are also discussed in this paper.