Solid-state Dye-sensitized Solar Cells Research Articles

1D Co4S3 nanoneedle array with mesoporous carbon derived from double comb copolymer as an efficient solar conversion catalyst

This study investigates the use of a one-dimensional (1D) cobalt sulfide/mesoporous carbon heterogeneous electrocatalyst as counter electrode for high solar energy conversion efficiency in dye-sensitized solar cells (DSSCs). The 1D cobalt oxide (Co3O4) was in situ hydrothermally grown on the fluorine-doped tin oxide glass substrate, followed by sulfurization to form 1D cobalt sulfide (Co4S3) nanoneedle array. The Co4S3 is characterized by a high electrocatalytic activity for reducing/oxidizing the redox couple in the electrolyte. Additionally, the 1D structural feature of the Co4S3 allows fast electron transport through the oriented diffusion pathway. However, the Co4S3 still has relatively low chemical stability and poor electrical conductivity than conventional Pt catalyst. Herein, we incorporated the mesoporous carbon layer derived from the double comb copolymer, i.e., PVDC-g-POEM, which can act as a mesoporous structural template and sufficient carbon source. This strategy increased the electrocatalytic activity and chemical durability of the heterogeneous catalytic materials. The 1D Co4S3/mesoporous carbon heterogeneous catalyst exhibited excellent electrocatalytic activity for the reduction of triiodide, thereby outperforming the conventional Pt counter electrode. The catalytic properties were demonstrated by electrochemical analysis, i.e., cyclic voltammetry and electrochemical impedance spectroscopy. Results suggest that solid-state DSSCs (ssDSSCs) fabricated with the 1D Co4S3/mesoporous carbon counter electrode exhibited a higher solar energy conversion efficiency of 6.2% than the corresponding ssDSSC with conventional Pt (5.7%). The pure 1D Co4S3 or mesoporous carbon showed relatively lower performance than conventional Pt. Accordingly, the 1D Co4S3/mesoporous carbon synergetic approach represents a new strategy for enhancing the catalytic activity and chemical stability for highly efficient ssDSSCs.

Enhancing the Photovoltaic Performance of Solid-State Dye-Sensitized Solar Cells with Composite Materials and Luminescent Down-Shifting

Dye-sensitized solar cells produce saturation of electrons and holes when exposed to high-intensity UV photons. These photon energies do not match the bandgap of the semiconductor materials, which not only degrades the dye and electrolyte but also disrupts the electron kinetics. In this work, graphene oxide (GO) was incorporated into TiO2 to form a composite photoanode structure. The results indicated that a composite photoanode based on GO/TiO2 enhanced the power conversion efficiency of a solid-state dye-sensitized solar cell (ss-DSSC) by 62% compared to that of pure TiO2. This enhancement is attributed to the high conductivity of graphene oxide. Further improvement in device performance was obtained by plasmonic luminescent down-shifting (LDS), where the UV region of the solar spectrum is shifted hundreds of nanometers. The multifunctional LDS coating layer was fabricated with a composite of ZnSe quantum dots and Ag nanoparticles. The experimental results demonstrated the ability of LDS to absorb photons at wavelengths below 400 nm and re-emit them at longer wavelengths (above 400 nm), where the cell has better photovoltaic response. When compared to a bare ss-DSSC, the power conversion efficiency (PCE) is enhanced by 37.62% for cells with a Ag/ZnSe coating layer. Moreover, the LDS-coated device exhibits 16.45% increased photon-to-current conversion efficiency compared to the LDS-free device for wavelengths lower than 500 nm. The 240-h aging tests confirmed that the LDS-coated ss-DSSC retained ∼ 83% of its original PCE value. This potential LDS coating layer not only leads to excellent device stability but also improves the cell performance, which increases the market value of the ss-DSSCs.

High-order diffraction grating as light harvesters for solar energy conversion

We prepared well-arrayed, diffraction gratings with different widths and periods using poly(dimethyl siloxane) (PDMS) stamps for efficient light harvesting in solar energy conversion devices. TiO2 gratings were applied onto the conductive or nonconductive sides of fluorine-doped tin oxide (FTO) glasses followed by Pt deposition, respectively. Their morphologies were characterized by field emission scanning electron microscopy (FE-SEM), and light reflection due to the gratings was observed with naked eyes. Further, the differences in light reflecting effects were determined using solid-state dye-sensitized solar cells (ssDSSCs) fabricated using the patterned counterelectrodes with the gratings. The ssDSSCs comprising NP-N counterelectrode (narrow patterned TiO2 layer on the nonconductive side of the FTO glass) showed an efficiency of 5.0%, which is higher than that of the conventional counterelectrode based on ssDSSCs (4.1%). This improvement is attributed to enhanced light harvesting, which was confirmed by incident photon-to-current efficiency measurements (IPCE).

Efficiency enhancement of solid-state dye-sensitized solar cells by doping polythiophene films photoelectrochemically grown onto TiO2 nanoparticles covered with cis-bis(isothiocyanato) bis(2,2′-bipyridyl-4,4′-dicarboxylato)ruthenium(II)

We recently reported on the effect of dopant sizes on the performance of polythiophene (PT)-based solar cells wherein the PT film was polymerized with 3-{5-[N,N-bis(4-diphenylamino)phenyl]thieno[3,2-b]thiophen-2-yl}-2-cyano-acrylic acid (C207) pre-adsorbed onto the electrode. Herein we utilized n- and p-doped polythiophene (PT) films as part of the solid-state dye-sensitized solar cell (ssDSSCs) based on cis-bis(isothiocyanato)bis(2,2′-bipyridyl-4,4′-dicarboxylato)ruthenium(II) (N3), the most commonly used dye sensitizer. Although the structure of the N3 is different from the chain-like C207, a smooth and homogeneous PT film can still be grown photoelectrochemically into the pores and onto the surface of the N3-covered TiO2 nanoparticles. The PT films were electrochemically doped with anions (ClO4− or PF6−) and cations (tetrabutylammonium, TBA+, or tetramethylammonium, TMA+). TMA+, being smaller, leads to a higher doping level in the PT films and a power conversion efficiency of 7.57 ± 0.33%, which is a 33% increase over that constructed with undoped PT films. However, the efficiency of the anion-doped PT films is reduced when compared to that of the undoped PT films. The N3-sensitized solar cell comprising a TMA+-doped PT film is 15% more efficient and costs at least 57% less than the PT-based solar cell comprising C207. This study demonstrates that the n-doped PT film can be a useful interfacial modifier, and pre-adsorbed N3 not only assists the growth of smooth PT films, but also enhances light absorption and power conversion efficiency of the resultant DSSC.

A stable gel electrolyte based on poly butyl acrylate (PBA)-co-poly acrylonitrile (PAN) for solid-state dye-sensitized solar cells

This work deals the preparation of a new polymer gel electrolyte using an efficient poly (acrylonitrile)-co-poly (butyl acrylate) (PAN-co-PBA) for solid-state DSSCs. Prepared PAN-co-PBA exhibited the superabsorbent behavior as seen the carboxylate group in copolymer. An excellent gelation with iodide couple and high ionic conductivity of 3.86 mS/cm were recorded for PAN-co-PBA gel electrolyte. Fabricated DSSC with 7% PAN-co-PBA attained the highest overall conversion efficiency of ~5.23% along with high JSC = 13.16 mA/cm2, VOC = 0.646 V and FF = 0.62. Improved DSSC performance might be related to excellent gelation and high ionic conductivity of PAN-co-PBA gel electrolyte, resulting in improving interfacial contact and pore filling.

Review on mixed cation effect in gel polymer electrolytes for quasi solid-state dye-sensitized solar cells

This paper reviews the efforts made to enhance the power conversion efficiencies of dye-sensitized solar cells (DSCs) by employing binary and ternary iodides in gel polymer electrolytes. Reported studies about mixed cation effects in quasi-solid-state electrolytes have been investigated using polyacrylonitrile (PAN), polyvinylidene fluoride, polyvinyl alcohol, polyethylene oxide, polymethylmethacrylate, and phthaloylchitosan as host polymers, with PAN being the most commonly employed. Ionic conductivities, their dependence on the composition of iodide salts, and the nature of counterion have been studied by preparing many different sets of gel polymer electrolytes. DSCs that were fabricated and characterized using different gel polymer electrolytes containing binary salt combinations showed efficiency enhancements. The general trend of open-circuit voltage (Voc) is to increase with an increasing radius of counterion, while short-circuit current density (Jsc) tends to be enhanced with reducing the size of the counterion in the cell. This behavior has been confirmed by studying single salt systems based on alkali metal iodides as well as quaternary ammonium iodides. The studies emphasized a significant enhancement of cell performance for binary cationic systems with respect to their single cation counterparts. In conclusion, the efficiency of the DSCs can be improved by employing a mixed cationic system with high and low charge densities.

Synthesis, Characterization, and Photovoltaic Performance of CdO-Based Nano Hybrid Material in Solid-State Dye-Sensitized Solar Cells

Abstract Cadmium oxide nanoparticles (NPs) were successfully synthesized through the simple and low-cost sol–gel method. The optical, morphological, compositional, and structural properties of as-synthesized NPs were investigated by ultraviolet–visible (UV/Vis) spectroscopy, fluorescence spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), Fourier transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD) analysis. Absorption spectra of CdO NPs were used for band gaps calculation, which was found to be 2.11 eV. The XRD pattern was used to investigate the purity and crystalline nature of NPs. Morphology and elemental composition were investigated by using SEM and energy-dispersive X-ray spectroscopy (EDX), respectively. FTIR assisted in identifying the functional groups and grafting of the dye on the surface of NPs. These CdO nanoparticles were photosensitized with Ru (II) based Z907 dye. Z907 dye was employed to extend the absorption spectrum of the material to the visible region of the solar spectrum so as to harvest the maximum amount of solar influx on the surface of earth. The energy level diagram revealed that the interaction among the constituents of the nanohybrid assembly permitted the flow of the electron in a cascade manner from dye to CdO nanoparticles. The synthesized photoactive nanohybrid material was thoroughly blended with poly (3-hexylthiophene), a solid electrolyte, and I–V measurements under simulated radiations 1000 W/m2 (AM 1.5) were recorded. A maximum induced photon to the current conversion efficiency of 0.60% was achieved.

Triphenylamine-based phenylhydrazone-indolium cationic dyes for solid-state DSSC applications

D-π-A architecture metal-free organic dyes, with a triphenylamine phenylhydrazone unit as electron donor and 5-carboxy-1-butyl-2,3,3-trimethyl-3H-indolium iodide as an electron withdrawing group, were designed and synthesized for solid-state dye-sensitized solar cells. These dyes demonstrate strong absorption between 500 and 800 nm, high molar extinction coefficient values (ε > 104) and have proper electronic energy levels as promising sensitizers.

Nanoscale Perovskite‐Sensitized Solar Cell Revisited: Dye‐Cell or Perovskite‐Cell?

A general and straightforward way of preparing few‐nanometer‐sized well‐separated MAPbIxBr3−x (MA=methylammonium) perovskite photosensitizers on the surface of an approximately 1 μm thick mesoporous TiO2 photoanode was suggested through a two‐step sequential deposition of low‐concentrated lead halides (0.10–0.30 m PbI2 or PbBr2) and methylammonium iodide/bromide (MAI/MABr). When those nanoscale MAPbIxBr3−x perovskites were incorporated as a photosensitizer in typical solid‐state dye‐sensitized solar cells (ss‐DSSCs), it could be verified clearly by the capacitance analysis that nano‐particulate MAPbI3 perovskites play the same role as that of a typical dye sensitizer (MK‐2 molecule) although their size, composition, and structure are different.

A Simplest, Cheapest and Most Efficienct Technique to Enhance the Performance of Solid State Dye-Sensitized Solar Cell: Deposition of Purple Seaweed as a Photosensitizer

Solid state dye-sensitized solar cell (ss-DSSC) was developed to overcome the problem arise from electrolyte leakage in liquid state dye-sensitized solar cell. This work focused on the fabrication of ss-DSSC based on inorganic semiconductor of titania and organic conducting polymer of poly (3-hexylthiophene) (P3HT) and natural dyes from purple seaweed (PS dyes) via electrochemical, spin coating and dip coating method, respectively. The absorption spectrum and functional group of PS dyes were investigated using UV-Visible absorption spectroscopy and Fourier Transform Infrared (FTIR) spectroscopy; respectively. Meanwhile, the effect of immersion time of PS dyes on performance of the device was studied via current density-voltage (J-V) characteristic. PS dye was absorbed in a wide range of solar spectrum in visible and near-IR region by chlorophyll a, phycocyanin and zeaxanthin pigments exists in the PS dyes. The present of carboxylic groups in PS dyes which bound to P3HT and formed P3HT-COOH enable the linkage to TiO2 surface which helps in the transfer of electrons from natural dyes to the conduction band of TiO2 film. The highest efficiency obtained was 1.44% at 10 minutes time of immersion. This concludes that PS dyes was a good photosensitizer and can be applied in ss-DSSC.

Facile graft copolymer template synthesis of mesoporous polymeric metal-organic frameworks to produce mesoporous TiO2: Promising platforms for photovoltaic and photocatalytic applications

Mesoporous polymeric metal-organic frameworks (mesoporous polymeric MOFs) are prepared on fluorine-doped tin oxide (FTO) substrate using hydrophilic terephthalic acid as the ligands, titanium isopropoxide as polymeric MOF precursors, and amphiphilic graft copolymers (i.e., poly(vinyl chloride)-graft-poly(oxyethylene methacrylate) (PVC-g-POEM) as structure-directing agents. The hydrophilic POEM chains in amphiphilic graft copolymers interact with the hydrophilic ligands and polymeric MOF precursors. Following thermal treatment at 500°C, mesoporous polymeric MOFs are transformed to mesoporous TiO2 with high specific surface area and crystallinity, suitable for photovoltaic and photocatalytic applications. Solid-state dye-sensitized solar cells (ssDSSCs) and dye-sensitized solar cells (DSSCs) fabricated with mesoporous TiO2 photoanodes have efficiencies of 7.45 and 8.43 % at 100mW/cm2, which is much higher than that of ssDSSCs and DSSCs with photoanodes of conventional TiO2 (5.36 and 7.14 %), respectively. The enhanced efficiency is attributed to good interconnectivity, larger surface area, and high porosity of the mesoporous TiO2, which results in suppressed interfacial charge recombination loss, enhanced electron transport, increased dye loading, and facilitated penetration of the electrolytes. Mesoporous TiO2 shows excellent activity as a photocatalyst for the degradation of humic acid under UV light irradiation.

Polyiodide solid-state dye-sensitized solar cell produced from a standard liquid I−/I3− electrolyte

Solid-state dye-sensitized solar cells were obtained by drying a standard I−/I3− liquid-electrolyte cell in ambient conditions.

Electrochemical Synthesis of PEDOT and Its Application in Solid-State Dye-sensitized Solar Cells

Electrochemical Synthesis of PEDOT and Its Application in Solid-State Dye-sensitized Solar Cells

Mechanistic Insights into Solid-State p-Type Dye-Sensitized Solar Cells

The study of p-type dye sensitized solar cells (p-DSCs) is appealing but challenging. Although the devices have been studied for 20 years, the light conversion efficiency lags far behind those of n...

Long-Term Stable Solid-State Dye-Sensitized Solar Cells Assembled with Solid-State Polymerized Hole-Transporting Material

The long-term stability of liquid-state dye-sensitized solar cells (liquid-DSSCs) is a primary problem for the upscaling and commercialization of this technology. The solid-state dye-sensitized solar cell (ss-DSSC) has been instigated to overcome the liquid-DSSC’s inherent production and instability issues and advancement has been made to achieve low-cost high-power conversion efficiency. The photovoltaic performance of ruthenium-based complex Z907 dye was studied in ss-DSSCs using a solid-state polymerized conductive polymer as hole-transporting material (HTM). We investigated the long-term stability of both liquid and solid-state DSSCs and the findings revealed an improved photovoltaic performance and long-term stability of ss-DSSC. This mainly depends on the transport phenomena of the HTM throughout the interface. The present results show a pavement for manufacturing highly stable and inexpensive ss-DSSC and the practical use is promising.

Solid-state Dye-sensitized Solar Cells Using (CH3NH3)2SnI6 Perovskite with Wideband Sensitizer

A wideband solid-state dye-sensitized solar cell was developed using a solution-processed (CH3NH3)2SnI6 perovskite film. This solar cell showed a photoelectric conversion over a wide range from the...

Facile Synthesis of Polyaniline-Single Wall Carbon Nanotube Nanocomposite as Hole Transport Material and Zinc Oxide Nanorodes as Metal Oxide to Integration Solid-State Dye-sensitized Solar Cells

Novel low-cost Polyaniline (PANI)-single wall carbon nanotubes (SWNT or SWCNT) nanocomposite - based hole transport materials (HTMs) as substitutes to the expensive HTM Spiro-OMeTAD have been synthesized and designed for the applications in solid-state dye-sensitized solar cell (DSSCs). The HTMs were prepared through a facile steps reaction from cheap starting material. These HTMs exhibit good solubility and charge-transport ability. The DSSCs based on PANI-SWNTs achieved power conversion efficiency (PCE) of 1.55% under air conditions, that is comparable to the cells employing the normally used Spiro-OMeTAD (1.827%). For DSSCs, we found that the solar cells synthesized based on vertical ZnO nanowire arrays by using a mixture paste of PMII, LiI and solid iodine as electrolyte SWNT enable better photovoltaic performance than that of pure PANI. These results show that easily synthesized PANI-SWNTs- HTMs have great prospect to replace the expensive Spiro-OMeTAD for DSSCs.

An Indacenodithieno[3,2-b]thiophene-Based Organic Dye for Solid-State p-Type Dye-Sensitized Solar Cells.

An indacenodithieno[3,2-b]thiophene (IDTT) unit is used as a linker moiety to design a new p-type dye-TIP-for solid-state p-type dye-sensitized solar cells. Solar cells based on the TIP dye offered an efficiency of 0.18 % with an open-circuit photovoltage of 550 mV and a short-circuit photocurrent density of 0.86 mA cm-2 , which is better than those of two reference dyes, PB6 and BH4. Charge lifetime experiments reveal that the IDTT linker-based TIP dye significantly suppresses charge recombination losses in the devices.

Focus-Induced Photoresponse Technique-Based NIR Photodetectors Containing Dimeric Polymethine Dyes

A group of near infrared (NIR)-absorbing dimeric polymethine dyes have been developed and successfully applied in photodetectors based on focus-induced photoresponse technology. The devices are based upon simple and inexpensive solid-state dye-sensitized solar cell architecture. The investigated molecules, designed and synthesized specifically for focus-induced photoresponse application, demonstrate relatively narrow and intense absorption in the NIR region of the spectrum up to 900 nm. Detectors containing the investigated dyes function in the near-infrared region of the spectrum, and suitable photocurrent and signal-to-noise ratio can be obtained at both 730 nm and 850 nm wavelengths. Additionally, these photodetectors can also be used in applications requiring simultaneous tracking of multiple light spots, as devices maintain appropriate characteristics at light modulation frequencies between 1 Hz and 1000 Hz.

Reduced graphene oxide on the performance of solid-state dye-sensitized solar cell

Dye-sensitized solar cell (DSSC) is a third generation solar cell which provides a good research platform for future photovoltaic technologies. DSSC can be categorized into two types based on the nature of its electrolyte, namely liquid and solid-state. In general, DSSC with liquid-based electrolyte has risk of electrolyte leakage. Therefore, the utilization of solid-state hole transport materials instead of liquid electrolytes can overcome the leakage issue of liquid-based DSSC. Despite of this advantage, the performance of solid-state dye-sensitized solar cell (SS-DSSC) is low compared to the cell that uses liquid electrolyte. To remedy this, doping with foreign materials is used to enhance the performance of the solar cell. Hence, this work focuses on the effect of reduced graphene oxide (RGO) on the performance of SS-DSSC utilizing TiO2 nanoparticles. The electrode samples were characterized with scanning electrode microscopy, energy dispersive spectroscopy, UV-Visible spectroscopy, IV test, and electrochemical impedance spectroscopy (EIS). By introducing RGO into SS-DSSC, the efficiency and fill factor was improved by at least 15%. Moreover, the presence of RGO increased the electron lifetime with higher recombination resistance as observed from EIS result.