Although efficiency of Dye Sensitized Solar Cell (DSSC) is still below the performance level of the market dominance silicon solar cells, in the last two decades DSSC has gathered sufficient ...interests because of the simplicity in device fabrication and low material cost, and therefore, DSSC is providing a possibility of solar cells production at a low entry cost. This review presents the research progress made in the implementation of natural pigments in DSSC. These pigments function as dye sensitizers and they play a major role in DSSC by absorbing light, and supplying electrons to the semiconductor matrixes in the cell. The common choices of dyes are the metal complexes, organic and/or natural dyes. A better efficiency with higher durability is observed for DSSC using metal complexes and organic dyes, however, the process of synthesizing these dyes is laborious, costly, and involves the use of toxic materials. As an alternative, natural pigments (dyes) found in plants such as anthocyanin, carotenoid, aurone, chlorophyll, tannin, betalain and many others are accepted as dyes in DSSCs. These natural pigments are easily obtained from fruits, flowers, leaves, seeds, barks and various parts of plants. Despite the limited performance of natural dyes, the prevailing advantages of natural dyes include high absorption coefficients, high light harvesting efficiency, low cost extraction and low toxicity. This review provides insight into the usage of the various natural pigments as sensitizers, the techniques to improve the pigments performance in DSSC, an outlook on the developmental work on the application of natural pigments in DSSC and their limitation. Additionally, the paper discusses the overall operation principle and the recent developments of each component of DSSC, as well as, comparing the material cost between natural dye and synthetic dye DSSC.
•Natural pigments have a promising future as sensitizers in DSSCs.•Anthocyanin, carotenoid, aurone, chlorophyll, tannin and betalain are among the natural pigments used as sensitizers.•Low-cost extraction, vast availability and eco-friendliness are major attractions of natural pigments.•The total fabrication cost for DSSC sensitized with chlorophyll is less than ~€ 2 per Watt peak.
A high‐purity methylammonium lead iodide complex with intercalated dimethylformamide (DMF) molecules, CH3NH3PbI3⋅DMF, is introduced as an effective precursor material for fabricating high‐quality ...solution‐processed perovskite layers. Spin‐coated films of the solvent‐intercalated complex dissolved in pure dimethyl sulfoxide (DMSO) yielded thick, dense perovskite layers after thermal annealing. The low volatility of the pure DMSO solvent extended the allowable time for low‐speed spin programs and considerably relaxed the precision needed for the antisolvent addition step. An optimized, reliable fabrication method was devised to take advantage of this extended process window and resulted in highly consistent performance of perovskite solar cell devices, with up to 19.8 % power‐conversion efficiency (PCE). The optimized method was also used to fabricate a 22.0 cm2, eight‐cell module with 14.2 % PCE (active area) and 8.64 V output (1.08 V/cell).
No rush: High‐efficiency CH3NH3PbI3 perovskite solar cells (19.8 % power‐conversion efficiency, PCE) and large‐area eight‐cell modules (14.2 % PCE, 8.64 V) were readily fabricated from a purified perovskite precursor material, CH3NH3PbI3⋅DMF (see picture). The low volatility of the pure DMSO solvent (as compared to DMF/DMSO) extended the allowable time for low‐speed spin programs and relaxed the precision needed for the antisolvent addition step.
In this work, we investigated the morphology, electrical conductivity, catalytic properties, and binding energies of electronic states of a system consisting of acetylene carbon black (AB) and ...graphite as efficient and low-cost counter electrodes (CEs) for dye-sensitized solar cells (DSSCs), where ratios of AB to graphite of 0:1, 1:3, 1:1, 3:1, and 1:0 were investigated. These carbon-based CEs were characterized using four-point probe conductivity measurement, field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), near-edge X-ray absorption fine structure (NAXAFS), electrochemical impedance spectrum (EIS), and current-voltage (I-V) performance. Introduction of small AB particles into graphite paste enhanced the electronic conductivity of AB-graphite composite due to the bridging of the graphite flakes for electrocatalytic activity of triiodide reduction. AB particles also offer large surface area to provide high electrochemical performance in DSSCs. The overall highest power conversion efficiency of 5.06% was achieved for the DSSC fabricated with a CE consisting of AB-graphite ratio of 3:1, which is comparable to the DSSC performance with conventional platinum (Pt) CE. These findings suggest that AB and graphite composite could be a promising CE for low-cost DSSCs.
Calcium (Ca) and lanthanum (La) doping into mesoporous TiO
2
prevents nucleation and growth of particles during synthesis and calcination at high temperature, resulting in smaller particle sizes and ...a decrease in the band gap of TiO
2
. These collectively have a positive affect on the efficiency of dye-sensitized solar cells (DSSCs) when employed as the anode. When designing an effective DSSC anode, the efficiency of dye adsorption must also be considered. This work investigates the adsorption properties of N719 dye onto La and Ca doped mesoporous TiO
2
anodes for DSSCs. Near edge X-ray absorption fine structure spectroscopy (NEXAFS) identified the presence of La and Ca dopants in the TiO
2
nanoparticles. Performance of DSSCs with Ca and La doped mesoporous TiO
2
anodes demonstrated that doping of TiO
2
enhances the overall efficiency of the devices. Both doped TiO
2
nanoparticles showed higher dye adsorption concentration than that of pure TiO
2
, as shown in Brunauer-Emmett-Teller (BET) characterization. By employing Langmuir and Freundlich isotherms, dye adsorption behaviour was modelled. Pure and Ca doped TiO
2
demonstrated good correlation to both isotherms, whereas La doped TiO
2
only showed good correlation with Langmuir isotherm. Irrespective of its single layer adsorption kinetics, 0.1 mol.% La doped TiO
2
has shown the highest dye adsorption and efficiency due to increase in surface area and oxygen vacancies induced by La doping.
In this article, we present the data collected from the fabricated carbon black-graphite counter electrode for dye-sensitized solar cells (DSSC) by incorporating binders such as titanium (IV) ...isopropoxide (TTIP), and zirconium (IV) dioxide (ZrO2). The addition of binders to the carbon black-graphite composite (CB/Gr) can drastically improve the adherence between the counter electrodes and the fluorine-doped tin oxide (FTO) substrate, surface area and the interparticle connection between the carbon materials. These data are presented which comprise of the resistivity measurements, scanning electron microscopy (SEM) with energy dispersive X-ray (EDX), and near-edge X-ray absorption fine structure (NEXAFS). The collection of this data was performed at room temperature. Detailed analysis of the data can be found in 1.
Hole transport material-free carbon-based perovskite solar cells (HTM-free C–PSCs) are recognized as a cost-effective and stable alternative to conventional perovskite solar cells. However, the ...significant energy level misalignment between the perovskite layer and the carbon counter electrode (CE) results in ineffective hole extraction and unfavorable charge recombination, which decreases the power conversion efficiency (PCE). Here, we report the introduction of metal salts (Al, Ca, and Mg) into graphite/carbon black (Gr/CB) CEs to modify the work function and enhance the hole selectivity of the CE. This modification leads to improved energy level alignment, efficient hole extraction, and reduced charge recombination. The PCE of the HTM-free C-PSC based on Al-modified Gr/CB as the CE material reached 9.91%, which is approximately 12% higher than that of devices employing unmodified Gr/CB CEs. This work demonstrates that by directly incorporating metal salts into the Gr/CB CE, the energy level alignment and hole extraction at the perovskite/carbon interface can be improved. This presents a viable method for enhancing the PCE of HTM-free C–PSCs.
Cyanidin is widely considered as a potential natural sensitizer in dye-sensitized solar cells due to its promising electron-donating and electron-accepting abilities and cheap availability. We ...consider modifications of cyanidin structure in order to obtain broader UV-Vis absorption and hence to achieve better performance in DSSC. The modified molecule consists of cyanidin and the benzothiadiazolylbenzoic acid group, where the benzothiadiazolylbenzoic acid group is attached to the cyanidin molecule by replacing one hydroxyl group. The resulting structure was then computationally simulated by using the Spartan’10 software package. The molecular geometries, electronic structures, absorption spectra, and electron injections of the newly designed organic sensitizer were investigated in this work through density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations using the Gaussian’09W software package. Furthermore, TDDFT computational calculations were performed on cyanadin and benzothiadiazolylbenzoic acid separately, as reference. The computational studies on the new sensitizer have shown a reduced HOMO-LUMO gap; bathochromic and hyperchromic shifts of absorption spectra range up to near-infrared region revealing its enhanced ability to sensitize DSSCs.
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•Dye agglomeration and masking effects are reduced by fractionation.•Fractions are characterized using UV–Vis, fluorescence, FTIR and CV.•DSSCs sensitized with fractions exhibited ...high efficiencies.•Photovoltaic parameters are discussed using TPV and EIS data.
An improvement in the efficiency of Ixora (Ixora sp. (Rubiaceae)) floral dye sensitized solar cells (DSSCs) has been achieved by diminishing the pigment’s interactions. Liquid column chromatography (LCC) separated the dye components, namely aurone, pelargonidin, and derivatives of cyanidin & malvidin, showed improved photovoltaic performance when compared to cells sensitized by the original dye extract of Ixora. The LCC separated dye components were analyzed using UV–Vis, fluorescence and Fourier transform infrared (FTIR) spectroscopic studies. The highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LUMO) and band gaps of the dyes were investigated. The DSSC prepared with the LCC separated dye showed energy conversion efficiencies (ECEs) ranging from 0.203% to 0.951%, whereas the original Ixora dye sensitized cell showed an ECE of 0.381%. Transient photovoltage (TPV) measurements and electrochemical impedance spectroscopy (EIS) were used to elucidate the photovoltaic parameters.
The use of anthocyanin dyes extracted from epidermal leaves of Tradescantia spathacea (Trant) and petals of Ixora coccinea (IX) was evaluated in the application of dye-sensitized solar cells (DSSCs). ...Subsequently, cocktail anthocyanin dyes from these dyes were prepared and how they enhanced the cell’s overall performance was assessed using five different volume-to-volume ratios. Cocktail dyes absorbed a wider range of light in the visible region, thus increasing the cell efficiencies of the cocktail dyes when compared to the DSSC sensitized by individual dyes. The surface charge (zeta-potential), average size of aggregated anthocyanin molecules (zetasizer), and anthocyanin stability in different storage temperatures were analyzed and recorded. Lower size of aggregated dye molecules as revealed from the cocktail dyes ensured better adsorption onto the TiO2 film. Tradescantia/Ixora pigments mixed in 1 : 4 ratio showed the highest cell efficiency of η=0.80%, under the irradiance of 100 mW cm−2, with a short-circuit current density 4.185 mA/cm2, open-circuit voltage of 0.346 V, and fill factor of 0.499. It was found that the desired storage temperature for these cocktail dyes to be stable over time was −20°C, in which the anthocyanin half-life was about approximately 1727 days.
Chlorophyll and xanthophyll dyes extracted from a single source of filamentous freshwater green algae (Cladophora sp.) were used to sensitize dye sensitized solar cells and their performances were ...investigated. A more positive interaction is expected as the derived dyes come from a single natural source because they work mutually in nature. Cell sensitized with mixed chlorophyll and xanthophyll showed synergistic activity with improved cell performance of 1.5- to 2-fold higher than that sensitized with any individual dye. The effect of temperature and the stability of these dyes were also investigated. Xanthophyll dye was found to be more stable compared to chlorophyll that is attributed in the ability of xanthophyll to dissipate extra energy via reversible structural changes. Mixing the dyes resulted to an increase in effective electron life time and reduced the process of electron recombination during solar cell operation, hence exhibiting a synergistic effect.
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