Quasi-solid Dye-sensitized Solar Cells Research Articles

Low Cost and Strongly Adsorbed Melamine Formaldehyde Sponge Electrolyte for Nontraditional Quasi-Solid Dye-Sensitized Solar Cells

Low Cost and Strongly Adsorbed Melamine Formaldehyde Sponge Electrolyte for Nontraditional Quasi-Solid Dye-Sensitized Solar Cells

Photovoltaic studies on iodine incorporated titania aerogel nanocomposites

Iodine incorporated titania aerogel nanocomposites were synthesized by the sol–gel method. The nanocomposites were obtained by varying the concentration of iodine as 0, 5, 10, and 20% with respect to the weight percentage of titania. All the synthesized nanocomposites retained the crystallinity and anatase phase, confirmed by X-ray diffraction studies. High-resolution scanning electron microscope images of nanocomposites showed the porous structure with agglomeration by increasing the concentration of iodine. The energy dispersive spectrum revealed the entry of the iodine into the titania aerogel. The absorption edge of the nanocomposites from the UV–Visible spectroscopy showed the red-shifted and thereby reducing the band gap with increasing iodine concentration. The photovoltaic performance of the synthesized iodine-incorporated titania aerogel nanocomposites was performed using as photoanode in the quasi-solid dye-sensitized solar cell and found that the efficiency is increasing with increasing iodine in titania aerogel. The photostability and reproducibility of the device were greater than the pristine aerogel.

Effect of deoxycholic acid co-sensitization in porphyrin dye on quasi-solid dye-sensitized solar cells comprising titania aerogel with a large surface area

Herein we have reported the effects of deoxycholic acid (DCA) and porphyrin sensitization on the photovoltaic characteristics of titania aerogel-incorporated quasi-solid dye-sensitized solar cell (QS-DSSC). The obtained results showed that the co-adsorption with DCA results in improving the photovoltaic parameters such as photocurrent density (Jsc), Open-circuit voltage (Voc), fill factor (FF) and overall power conversion efficiency (η). For example, the device treated with DCA (labelled as DCA-1) delivered PCE (η) of 2.56 % (with Voc of 0.61 V), which is greater than those obtained for the unchanged device (labelled as 1) (η = 0.97 %, Voc = 0.53 V). The prime factors responsible for the above enhancement are increased electron injection, suppressed recombination and low electron transport resistance, as confirmed by the analysis of photoluminescence (PL) spectra, dye adsorption measurements, electrochemical impedance spectra (EIS) and time-dependent transient spectra for photocurrent /photovoltage.

Designing highly effective mesoporous Carbon-based counter electrodes for liquid Electrolyte-based and Quasi-solid Dye-sensitized solar cells

In this study, nitrogen-doped mesoporous carbon (NMC) and boron-doped mesoporous carbon (BMC) are synthesized and used as Pt-free counter electrode (CE) materials for dye-sensitized solar cells (DSCs). The optimized NMC and BMC CEs exhibit significantly higher catalytic activities than the pristine mesoporous carbon (MC). The I-/I3- in acetonitrile liquid electrolyte-based DSCs have power conversion efficiencies (PCE) of 7.20% with the NMC CE and 7.15% with the BMC CE, which are significantly higher than that obtained using the MC CE (5.88%). This is attributed to the improved effective catalytic active sites and the enhanced electrical conductivities of the NMC and BMC CEs. When Pt with trace amounts (0.1 wt%) is loaded on NMC, the liquid DSCs using Pt/NMC composite CEs yield PCE values of 8.31% and 9.92%, respectively, under 1.0 Sun and 0.1 Sun illumination. The Pt/NMC CE is further employed in quasi-solid DSCs, which also give a high PCE of 8.15% under 1.0 Sun illumination. A flexible Pt/NMC CE is also prepared on indium tin oxide-polyethylene naphthalate (ITO-PEN) substrate, and the generated liquid DSCs show a PCE of 6.92%. This work provides a feasible path to enhance the catalytic activity of the MC CE in DSCs.

Studies on the silver incorporated titania aerogel nanostructure as a photoanode in quasi solid dye- sensitized solar cells

Dye-sensitized solar cells (DSSC) have a significant impact on photovoltaic technology because of their quick, low-cost manufacture, light weight, and high power conversion efficiency (PCE). Numerous research works were undergone on different titania nanostructure used as photoanode in DSSC. High surface area titania nanoarchitecture has effective for more dye absorption to improve the cell performance. Titania aerogels have a high specific surface area and high porosity compared to other titania nanostructures. Incorporation of noble metals into titania aerogel enhanced PCE. In noble metals, silver has promising material because of its cost-effective, less ohmic resistance etc. compared to Au. In this work, we prepared silver doped titania aerogel and studied its photovoltaic performance in the quasi solid DSSC performance. Silver-incorporated titania aerogel was synthesized by the facile sol–gel route. Structural, optical, photovoltaic properties and cell stability of a prepared photoanode material were measured. PXRD revealed that the anatase phase is retained after the incorporation of silver. HRSEM images and EDS spectra confirmed the interconnecting network of titania aerogel and the presence of silver respectively. Due to the Localized Surface Plasmonic Resonance (LSPR) effect, the absorption spectra of the composite exhibited a red-shift around 650 nm. PL spectra showed the decreasing intensity in composites which is the evidence of suppressing electron-hole recombination and improving electron injection. The incorporation of silver has improved the photon absorption capability of the photoanode tends to enhance photocurrent density as well as PCE of QS-DSSC.

Polydopamine-Modified Electrospun Polyvinylidene Fluoride Nanofiber Based Flexible Polymer Gel Electrolyte for Highly Stable Dye-Sensitized Solar Cells.

To overcome the drawbacks of solvent evaporation and leakage from the liquid electrolyte in dye-sensitized solar cells (DSSCs), a polymer gel electrolyte (PGE), based on polydopamine (PDA)-modified electrospun polyvinylidene fluoride (PVDF) nanofibers, PDA@PVDF, was prepared and applied in quasi-solid DSSCs (QS-DSSCs). The PDA coating increased the wettability of the liquid electrolyte by improving the distribution of the ionic liquid electrolyte. This, in turn, enhanced the ion conductivity of the PGE as well as the stability of QS-DSSC. The PDA@PVDF nanofiber membrane exhibited a satisfactory ultimate tensile strength of 9.3 MPa with a failure elongation of 130%. Such high toughness provided excellent mechanical support for the PGE. Owing to the unique pore connected structure of nonwoven nanofibers as well as the reduced surface tension with the liquid electrolytes, the PGE-based QS-DSSC retained 95.7% of the short circuit current from the liquid-electrolyte-based DSSC and showed an energy conversion efficiency of 8.26%. No significant impacts were observed for the open-circuit voltage and fill factor. More importantly, the QS-DSSCs using PDA@PVDF-based PGE showed a significantly improved solar cell stability under both indoor and outdoor conditions.

Effects of concentrated light on the performance and stability of a quasi-solid electrolyte in dye-sensitized solar cells

In this study, a quasi-solid dye-sensitized solar cell (QSDSSC) and a liquid DSSC were coupled with a concentric mirror. Under focused concentrated light, the QSDSSC exhibited higher performance stability when compared to the liquid DSSC, which showed remarkably low stability due to the leakage and evaporation of the liquid electrolyte. The QSDSSC retains ~91.4% of its initial efficiency after 120 mins, while the liquid DSSC retains only ~73.2%. The enhanced stability of the QSDSSC is attributed to the 3D frame formed by the nanofillers and polymers, which effectively prevent evaporation and leakage of the electrolyte.

Ionic liquid infused starch-cellulose derivative based quasi-solid dye-sensitized solar cell: exploiting the rheological properties of natural polymers

Starch and cellulose have long been used in various industrial applications as gelating agents. In this work, the intrinsic adhesive properties of these biopolymers are exploited for application as electrolytes in DSSC. Firstly, potato starch was chemically modified into phthaloyl starch in a facile esterification process. Fabrication of polymer electrolyte with phthaloyl starch (PhSt) and hydroxyethyl cellulose (HEC) incorporated with dimethylformamide and tetrapropylammonium iodide produced homogeneous gels with diminished crystallinity. Infusion of different weight percentages of 1-butyl-3-methylimidazolium iodide (BMII) into the gels were revealed to further suppress polymer crystallinity and elevate ionic conductivity. Rheological analysis revealed that addition of up to 6 wt% of ionic liquid aid in elevating the rigidity, strength and tackiness of the gels. The improved adhesiveness of the gels can be correlated to effective reduction of interfacial resistance and restraining of recombination reactions based on electrochemical impedance spectroscopy. Quasi-solid DSSC fabricated with PhSt-HEC with 8 wt% of BMII exhibited enhanced short-circuit current density, JSC and fill factor, contributing to an optimized efficiency of 5.20%.

Organosoluble, esterified starch as quasi-solid biopolymer electrolyte in dye-sensitized solar cell

Fabrication of quasi-solid state polymer electrolytes are recently being endorsed by electrochemists due to its superior electrical and physical properties. With the aspiration to develop a sustainable electrolyte component, this study is a novel attempt to fabricate quasi-solid electrolyte based on esterified starch. Potato starch was chemically modified via simple phthaloylation method. The resulting amorphous, hydrophobic starch derivative was used as a polymer base to prepare cost effective thermoplastic gel electrolytes via incorporation of propylene carbonate, dimethylformamide and lithium iodide. Fourier transform infrared spectroscopy and X-ray diffraction characterizations verified the impact of phthaloylation and plasticization in suppressing the crystallinity and hydrophilicity of starch. The biopolymer gel with 40 wt.% LiI recorded the highest room temperature ionic conductivity of 4.82 mS cm−1. The sample with highest ionic conductivity recorded the best efficiency of 3.56%, which is one of the highest values for starch electrolyte-based dye-sensitized solar cells (DSSC). The optimized efficiency indicate that starch-based electrolyte has good prospects for fabrication of quasi-solid DSSC.

Dye-sensitized solar cells based on MK2 dye, PMMA-based quasi-solid electrolyte, and flexible CNT counter electrode

In this paper, a dye-sensitized solar cell based on organic MK2 dye, a quasi-solid electrolyte, and a flexible counter electrode was investigated. Two types of TiO2 nanoparticles with different sizes were used to make the photoanode with a bi-layer structure. The quasi-solid electrolyte was made based on polymethylmethacrylate (PMMA) and iodide/triiodide couple. The counter electrode was fabricated by electrophoresis deposition of carbon nanotube (CNT) mixed with diallyl dimethylammonium chloride (PDDA) on a flexible stainless-steel mesh. A cellulose separator was used to improve the stability of the solar cell. A simple and low-cost sealing method using polypropylene-based tape has been proposed and used for conducting the stability test. The maximum conversion efficiency of 2.5% (under simulated AM 1.5) was obtained with the fabricated quasi-solid dye-sensitized solar cells.

Porphyrin-sensitized quasi-solid solar cells with MOF composited titania aerogel photoanodes

ZnTPP-COOH porphyrin-based quasi-solid dye-sensitized solar cells were fabricated with the following three different photoanode materials: Ni-MOF@titania aerogel composite, Cu-MOF@titania aerogel composite, and pure titania aerogel. Their photovoltaic performances were investigated through photocurrent–photovoltage (J–V) curve, electrochemical impedance spectroscopy (EIS), intensity modulated photocurrent spectroscopy, and transient measurements of photocurrent and photovoltage decay. Among the three cells, the enhancement of photocurrent is observed in cells containing Ni-MOF@titania aerogel photoanodes. As a result, the Ni-MOF@titania aerogel photoanode–based cell achieved the highest photocurrent density of 8.88 mA/cm2 and power conversion efficiency of 2.34%. This value is higher than that of the other two devices. Moreover, the EIS analysis is used to understand better the possible electron transfer behind the photocurrent boosting in Ni-MOF@titania aerogel photoanode–based cell. Low Rct value (44.1 Ω) and low τd value of the Ni-MOF@titania aerogel device are the key factors to improve the electron flow, the Warburg diffusion of electrolyte, as well as the regeneration process. These factors are attributed as the reason for their best performance among other devices. Based on the results obtained, the plausible mechanism for electron transfer is discussed using the energy level cascades of TiO2/MOF/porphyrin dye. The transient measurements indicated that the devices exhibited good reproducibility under multiple illuminations.

Flexible carbon nanotubes/TiO2/C nanofibrous film as counter electrode of flexible quasi-solid dye-sensitized solar cells

Flexible counter electrode (CE) is a key to develop flexible dye-sensitized solar cells (DSSCs). To obtain flexible CE with well electro-catalytic activity, the carbon nanotubes (CNTs) were employed to modify the flexible TiO2/C nanofibrous film. All the CNTs/TiO2/C nanofibrous film with incorporation of CNTs into TiO2/C nanofiber showed pleasurable flexibility. In addition, the specific surface area, the conductivity, and the electro-catalytic activity of the nanofibrous film increased as the content of CNTs increased, reaching the largest values before decreasing. The CNTs/TiO2/C nanofibrous film with 2% of CNTs incorporation possessed optimal electro-catalytic activity. Therefore, the conversion efficiency of the flexible quasi-solid DSSCs based on the nanofibrous film CE was greatly enhanced and the highest conversion efficiency of about 3.4% was achieved. Besides, the properties of the CNTs/TiO2/C nanofibrous film almost remained constant after 50 cycles with the bending radius of 1 mm and the twisting angle of 10π, implying that it exhibited excellent bending stability and twisting stability. The flexible CNTs/TiO2/C nanofibrous film has a huge potential in flexible devices.

Organosoluble Starch-Cellulose Binary Polymer Blend as a Quasi-Solid Electrolyte in a Dye-Sensitized Solar Cell.

This work is a pioneer attempt to fabricate quasi-solid dye-sensitized solar cell (QSDDSC) based on organosoluble starch derivative. Rheological characterizations of the PhSt-HEC blend based gels exhibited viscoelastic properties favorable for electrolyte fabrication. From amplitude sweep and tack test analyses, it was evident that the inclusion of LiI improved the rigidity and tack property of the gels. On the other hand, the opposite was true for TPAI based gels, which resulted in less rigid and tacky electrolytes. The crystallinity of the gels was found to decline with increasing amount of salt in both systems. The highest photoconversion efficiency of 3.94% was recorded upon addition of 12.5 wt % TPAI and this value is one of the highest DSSC performance recorded for starch based electrolytes. From electrochemical impedance spectroscopy (EIS), it is deduced that the steric hindrance imposed by bulky cations aids in hindering recombination between photoanode and electrolyte.

Highly interconnected porous TiO2-Ni-MOF composite aerogel photoanodes for high power conversion efficiency in quasi-solid dye-sensitized solar cells

Three-dimensional mesoporous TiO2-Ni-MOF composite aerogels were synthesized via sol–gel route and used as photoanode materials for quasi-solid dye-sensitized solar cell (QSDSC) applications. The assessment of their photovoltaic performance revealed an enhancement compared to pure aerogel-based QSDSCs; the maximum photo-conversion efficiency of the fabricated photoanode was 8.846% for 0.5% composite aerogel, which is ~30% higher than that of pure aerogel-based ones (6.805%). The achievement of other key factors required for efficiency enhancement such as increased photocurrent density, reduced charge-transfer resistance, and suppressed electron recombination was confirmed by photocurrent density–applied voltage curves and electrochemical impedance measurements. The surface area of the composite aerogels ranged between 269 and 233 m2 g−1, which make them promising candidates for high-efficiency QSDSCs.

Novel Quasi-Solid-State Electrolytes based on Electrospun Poly(vinylidene fluoride) Fiber Membranes for Highly Efficient and Stable Dye-Sensitized Solar Cells

To obtain new highly efficient and stable quasi-solid dye-sensitized solar cells (QS-DSSCs) that can meet the requirements for the large-scale commercial application of solar cells, we have developed a novel quasi-solid-state electrolyte, based on an electrospun polyvinylidene fluoride (PVDF) membrane. The structure and properties of electrospun PVDF membranes were characterized by scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), thermogravimetric (TG), and mechanical testing. The results indicate that the electrospun PVDF membrane has a three-dimensional network structure with extremely high porosity, which not only acts as a barrier to prevent electrolyte leakage but also provides a channel for the transmission of ions in the electrolyte, thereby effectively guaranteeing the high photoelectric conversion efficiency of the cells. The membrane was observed to withstand the conditions of hot-press (110 °C), and exhibited good thermal stability and mechanical strength, which are critical for the long-term stability and safety of the cells. The photovoltaic characteristics and stabilities of QS-DSSCs were compared with DSSCs based on an ionic liquid electrolyte (L-DSSC). QS-DSSCs with an 80 μm thick nanofiber electrolyte membrane showed a conversion efficiency of 8.63%, whereas an identical cell based on the corresponding ionic liquid electrolyte showed an efficiency of 9.30%. The stability test showed that, under indoor and outdoor conditions, after 390 h, the L-DSSCs failed. Meanwhile, the QS-DSSCs also maintained 84% and 77% of the original efficiency. The results show that, compared to the liquid electrolyte, the design of the quasi-solid electrolytes based on electrospun PVDF nanofiber membrane not only demonstrates the high conversion efficiency of DSSCs but also enhances the stability of the DSSCs, which provides the possibility for the fabrication of solar cells with higher efficiency and stability.

Novel stainless steel based, eco-friendly dye-sensitized solar cells using electrospun porous ZnO nanofibers

Herein, we report a new type of eco-friendly, cost-effective stainless steel mesh-based flexible quasi-solid dye-sensitized solar cell (DSSC) using electrospun ZnO nanofibers as the photoelectrode. The electrospun ZnO nanofibers showed enhanced surface to volume ratio due to the high porosity of the fibers composed of ZnO grains having 12–20 nm size with high interconnectivity. For DSSCs fabrication, commonly available natural dye chlorophyll was extracted from the Neem plant and used as the dye sensitizer. An overall solar cell conversion efficiency of 0.13 % was observed for the assembled DSSC with a short-circuit photocurrent, open-circuit voltage and fill factor of 28 μA, 0.321 mV and 32.77 %respectively. The present approach to develop cost-effective and eco-friendly DSSCs would open up enormous possibilities in effective harvesting of solar energy for commercial and rural area applications

Components control for high-voltage quasi-solid state dye-sensitized solar cells based on two-phase polymer gel electrolyte

For the quasi-solid-state electrolyte in dye-sensitized solar cells (DSSCs), the selection and optimization of components is a decisive process for high photovoltaic performance while maintaining stability. In this work, a two-phase polymer gel system based on PEO and PEGDME formed by chemical crosslinking is used as quasi-solid electrolyte in DSSCs. Through components of preparation solvent, iodine and GuSCN control, the photoelectric conversion efficiency of QS-DSSCs reaches 7.66%, especially the open-circuit voltage reaches 793 mV due to the self-assembly and ionic conductivity promotion. It lays a solid foundation for probing its potential value of quasi-solid dye-sensitized solar cells.

Anisotropic One-Dimensional Aqueous Polymer Gel Electrolyte for Photoelectrochemical Devices: Improvement in Hydrophobic TiO2–Dye/Electrolyte Interface

Aqueous photoelectrochemical devices have emerged recently as promising area because of their economic and ecological friendliness. In the present work, we have expedited surface active amphiphilic quasi-solid aqueous polymer gel electrolyte (PGE) with hydrophobic sensitizer SK3 in water-based dye sensitized solar cell (DSSC). PGE was prepared from amphiphilic block copolymer (PEO)–(PPO)–(PEO) with iodide–triiodide couple in pure aqueous media without any organic solvent. This block copolymer, with iodide-triiodide salt exhibits 1D-lamellar microcrystalline phase which shows stability in the temperature range of 25–50 °C. Parallel (||al) and perpendicular (⊥ar) alignment of anisotropic lamellar microcrystalline phase pertaining by PGE were characterized and applied in quasi-solid DSSC. Temperature dependency of ionic conductivity, triiodide diffusion, differential scanning calorimetry, viscosity, and 1-D lamellar anisotropic behavior were studied. Surface active effect of PGE at the hydrophobic dye sensit...

$$\hbox {TiO}_{2}$$ TiO 2 aerogel–metal organic framework nanocomposite: a new class of photoanode material for dye-sensitized solar cell applications

$$\hbox {TiO}_{2}$$ aerogel–metal organic framework (MOF) nanocomposite was synthesized using sol–gel method followed by subcritical drying technique and employed as a photoanode material in quasi-solid dye-sensitized solar cells (DSSCs). The nanocomposite material showed a BET surface area of $$250\hbox { m}^{2}\hbox { g}^{-1}$$ with an average pore size of 5 nm. Field emission scanning electron microscopic images revealed the continuous arrangement of pore-solid network structure. Energy-dispersive X-ray analysis shows the presence of MOF clusters on $$\hbox {TiO}_{2}$$ aerogel network. X-ray photoelectron spectroscopic analysis also supports the presence of MOF clusters in the aerogel network and indicates the presence of some oxygen vacancies in the nanocomposite material. The $$\hbox {TiO}_{2}$$ aerogel–MOF nanocomposite was used as photoanode in DSSC and an overall power conversion efficiency 2.34% along with a short-circuit current density 6.22 mA $$\hbox {cm}^{-2}$$ was achieved.

Microwave assisted synthesis of high surface area TiO2 aerogels: A competent photoanode material for quasi-solid dye-sensitized solar cells

TiO2 aerogels are 3-dimensional interconnected network structures offer high surface area, large pores and low density. In the present work, we synthesized TiO2 aerogels by a microwave assisted sol-gel method and employed it as a photo-anode material in quasi-solid dye-sensitized solar cells (QSDSSCs). This work mainly focuses on the effect of microwave irradiation on primary TiO2 nanoparticles, the building blocks of the aerogel network. The crystallite size determined from X-ray diffraction indicates that the crystal growth was controlled, as the particle-particle attraction prevailed by the thermal effect instigated during microwave irradiation. The smaller crystals enhanced the surface area of TiO2 aerogels and the amount of dye adsorption. The porous morphology and the interconnected network structure of aerogels were ascertained by Field Emission Scanning Electron Microscope (FESEM) and Transmission Electron Microscopic (TEM) analysis. A maximum power conversion efficiency of 5.2% with a short-circuit current density of 15.18 mA/cm2 and an open circuit voltage of 0.62 V was realized by utilizing TiO2 aerogel as photoanode in QSDSSCs.