How Do Dye Sensitized Solar Cells Work?
- The dye functions as the photoactive material of the DSSC. When light comes into contact with the dye, photons of light...
- The dye uses energy from these photons to excite electrons in the cell, behaving like chlorophyll in photosynthesis.
- The dye injects this excited electron into the titanium dioxide in the DSSC.
What is a dye sensitized solar cell (DSSC)?
The dye sensitized solar cell, also known as DSSC or DSC, is a distinct type of photovoltaic (pv) cell which can effectively convert natural and artificial visible light into electrical energy. This new class of advanced solar cell mimics the natural absorption of light energy.
What is a dye-sensitized solar cell?
Dye-sensitized solar cells (DSSCs) are photovoltaic devices that are used to convert light energy into electrical energy by the use of organic dyes (photosensitizers) and semiconductors. They prove to the most economical and sustainable power supply for MEC applications because solar energy is the most abundant form of renewable energy.
Are solar cells more efficient than dye sensitized solar panels?
Although silicon solar cells are more efficient than dye sensitized solar cells, the former is essential as it can generate electricity in low light conditions. These solar cells can produce electricity even in indoor lights. Furthermore, these solar cells have a simple design and come at economical pricing.
How is dye used in solar cells?
For every solar cell you assemble, you will need an anode and a cathode. The anode will contain the dye and titanium dioxide molecules. Photons will excite the dye molecules' electrons, and the electrons will jump from the dye molecule to the titanium dioxide to the glass anode through diffusion.
What is the need of dye sensitized solar cells when we are already used to the silicon based solar cell systems?
Dye sensitized solar cells split the two functions supplied by silicon in a traditional cell design. The energy gotten through this simple dye sensitive cell can be collected to drive electrical system loads. The dye sensitized solar cell can produce electricity under low light conditions, including indoor lighting.
What is the difference between solar cell and dye sensitized solar cell?
In conventional solar cells, the semiconductor has the tasks of light absorption and charge-carrier transport, whereas in dye-sensitized solar cells, the two functions are separately controlled. A photosensitizing dye, anchored to the surface of a wide band gap semiconductor, absorbs light.
How long do dye sensitized solar cells last?
These molecules are responsible for light absorption and energy conversion in the device. DSSCs are more economical than commercial Si-based solar cells, but their lifetimes are limited (~6 years vs. 20-30 years of Si-based counterparts).
Can dye sensitized solar cells generate electricity in the dark?
Dye-sensitized solar cells that can generate electricity in the daytime and dark are fabricated by combining long persistence phosphors with mesoscopic TiO2 photoanodes.
What is the meaning of dye sensitized?
Dye-sensitized solar cells (DSSCs) use an organic dye to absorb incoming sunlight to produce excited electrons and create an energy which is then transferred to an inexpensive material, such as titanium dioxide (TiO2). From there, the energy is collected on a transparent conducting surface.
What are the disadvantages of dye sensitized solar cells compared to conventional solar cells?
The major disadvantage to the DSSC design is the use of the liquid electrolyte, which has temperature stability problems. At low temperatures the electrolyte can freeze, halting power production and potentially leading to physical damage.
What is the voltage of solar cell?
approximately 0.5 volts to 0.6 voltsIndividual solar cell devices are often the electrical building blocks of photovoltaic modules, known colloquially as solar panels. The common single junction silicon solar cell can produce a maximum open-circuit voltage of approximately 0.5 volts to 0.6 volts.
Why are perovskite solar cells important?
Perovskites are widely seen as the likely platform for next-generation solar cells, replacing silicon because of its easier manufacturing process, lower cost, and greater flexibility.
How do dye sensitized solar cells work?
11. It relies on the visible photoexcitation of dyes triggering an electron transfer into the conduction band of the metal oxide semiconductor (generally TiO 2) (equation I and II), followed by regeneration of the oxidized dye molecules by the electron donation from the redox couple in the electrolyte (equation III and IV) and finally migration of electron through the external load to complete the circuit ( Grätzel, 2000 ). The entire operation takes place with the help of different components of DSSC, such as the light-absorber (dye/sensitizer), the electron-transport agent (wide bandgap nanocrystalline semiconductor), and the hole-transport agent (redox couple in electrolyte). For successful conversion of sunlight to electrical power, all the components constituting the system should effectively play their role. Sensitizer/dye in particular should possess certain important features for efficient performance, namely, a broad and strong absorption from visible to near-infrared region, chemical stability of the appropriate lowest unoccupied molecular orbital and highest occupied molecular orbital levels for effective charge injection into the semiconductor, dye regeneration from the electrolyte, high-molar extinction coefficients in the visible, near-infrared region for light-harvesting, good photostability, and solubility to hamper the recombination.
What is a DSC solar cell?
DSC, as a third-generation solar cell technology, is a potential low-cost candidate to meet the increasing energy demand in the world . Since the first reports on this technology appeared, about 18,000 research articles have been published. These researches are focused on low-cost mass production of highly efficient, stable, flexible solar cells. In this regard, polymer-based composite materials used in flexible DSCs, their production methods, and effects on performance were reviewed in this chapter.
Why are DSSCs bad?
Due to the use of liquid electrolytes, cells with DSSC technology have thermal stability problems. At low temperatures the electrolytes may freeze, blocking the production of power and potentially causing physical damage. In contrast, high temperatures cause the expansion of the liquid, making the sealing of modules difficult. In addition, the electrolyte solutions contain volatile organic compounds, harmful to humans, requiring special care in sealing to prevent leakage due to galvanic corrosion. Replacing the liquid electrolyte with a solid one (solid-state DSSCs—ss-DSSCs) has been a major focus of research so far, since the use of a solid electrolyte eliminates these problems but decreases the efficiency of total conversion.
What is DSSC in electronics?
A DSSC involves a porous layer of the oxide semiconductor (the anode, i.e., the negative electrode) nanoparticles, with the nanoparti cles being coated with a molecular dye (e.g., a ruthenium-based complex), such that the nanoparticles are electrically in contact with one another to form a continuous conductive path (percolation).
What is a DSSC?
A dye-sensitized solar cell (DSSC) is an economical solar cell that comes in the category of thin-film solar cells. The DSSC has various striking merits: easy fabrication using the roll-to-roll technique as well as an economical and environmentally friendly nature, in the case of natural dyes. DSSC cells are designed and fabricated using four natural dyes: Celosia Cristata, Saffron, Cynoglossum, and eggplant peel. A maximum energy conversion efficiency of 1.38% was achieved by DSSC using Celosia Cristata as dye with a maximum absorbance of 510 nm as shown in Fig. 2.16 [39].
Can a PEC be integrated into an electrolytic cell?
The basic operational principles of such a device are described in Section 3.1. Since a PEC can be integrated into an electrolytic cell it is also an option that electrochemistry can give rise to a photoelectrolytic or a photosynthetic effect converting solar energy to chemistry.
How are DSSC and NG integrated?
DSSC, SC and NG can be integrated simultaneously on a single microsized fiber to realize solar and mechanical energy harvesting and subsequent storing, as presented in Fig. 16.3 [32]. NG, SC, and DSSC share a common substrate made from Au-coated polymethylmethacrylate (PMMA) fiber of diameter B220 mm. The Au layer serves as the common inner electrode. As an active piezoelectric material for NG, ZnO nanowires (NWs) were radially grown on the fiber. This ZnO layer also acts as a core material of the DSSC and also provides a large surface area for SC. As for the NG, graphene-coated copper meshes were wrapped around the fiber to serve as the outer electrode. Under a shear stress driven by a push action at 5 Hz, the peak output current and voltage were 2 nA and 7 mV, respectively. To fabricate the SC, a PVA/H 3 PO 4 gel electrolyte was filled in after the graphene-coated copper meshes were wrapped around the fiber. The SC showed a capacitance per unit length of 0.025 mF/cm. For the DSSC functionality, the as-grown ZnO-NWs were sensitized with a N719 dye solution, a ZnO NW-grown graphene sheet was wrapped around the fiber as the outer electrode, and finally a liquid electrolyte was poured in. The Jsc, Voc, FF, and PCE of the DSSC were 0.35 mA/cm 2, 0.17 V, 0.39, and 0.02%, respectively [32]. More of such research initiatives are required for commercial level success in this regard.
What is a photoanode made of?
The photoanode is made up of transparent conductive glass coated with transparent conductive oxide (indium- or fluorine-doped tin oxide; ITO and FTO, respectively), on which a dye-coated metal oxide semiconductor (thickness, 10–20 μm) is applied [2]. The metal oxide semiconductor layer has two functions, namely a support for the sensitizer and a carrier of photogenerated electrons from the dyes to the external circuit. The photocurrent efficiency (PCE) of DSSCs strongly depends on the dye sensitizer irradiation absorption, with the conversion efficiency of DSSCs reaching values ≤ 11% (ruthenium dye) and 13% (porphyrin dye) [5].
How does DSSC work?
The DSSC works as a photo-electrochemical cell, where the generation and transportation of electrons are caused by the combined effect of the photon energy and the chemical reactions. Although the DSSC has a bright future as a potential energy source with better integration possibilities, there are many aspects that need to be worked upon for its commercialization. One of the major challenges for DSSC is to increase the power conversion efficiency with better stability. The organic dye absorbs solar light to generate photo-excited electrons to be carried out to the external circuit through semiconductor photo-anode, and steady flow of current is obtained due to electrochemical effect. The semiconductor photo-electrode has a major role in the performance of DSSC, as recombination of the photo-generated carriers in semiconductors reduces the current that effectively decreases the power conversion efficiency of the cell. On the other hand, photo-anode should be highly transparent so that solar light reaches to the dye molecules. Historically, TiO 2 nanoparticles have been the most studied materials as DSSC photo-anode. There are also many research efforts to increase the performance of DSSC by using nanostructured and nanocomposite photo-anode to increase the charge transportation due to anisotropy in nanostructure geometry and less recombination possibility in nanocomposite materials. Carbon nanostructures have also been explored in various ways for the improvement of the PCE of DSSCs. Incorporation of CNTs in the titania (TiO 2) nanoparticle matrix significantly improved the cell efficiency. The DSSC structure fabricated with TiO 2 nanoparticles using CNT electrodes led to highly efficient cells attributed to better charge transport by CNTs [37]. The use of vertically aligned CNT forest has also increased the PCE of DSSCs by many folds [38].
What is a DSSC?
Dye-sensitized solar cell (DSSC) is another kind of solution-processed solar cells applying functional polymer component as electrode or hole transporting material. Basically, the structure of DSSC contains three parts, namely dye-sensitized photoanode, counter electrode, and redox electrolyte, which looks like a sandwich. The dye-sensitized photoanode is responsible for light absorbing and charge injection, while counter electrode is for redox pair reduction, and redox electrolyte or hole transporting material is for dye reduction. The mechanism of DSSC is depicted later. First, light travel through transparent electrode and is absorbed by dye to reach the excited state. Then the excited electrons would be injected into the conduction band of semiconductor metal oxide and transfer to external circuit. The oxidized dye would be reduced by redox pair in the electrolyte, which will be reduced by counter electrode with external circuit electrons to complete a circle. There are two grand challenges facing DSSC, as high cost platinum counter electrode and corrosive liquid electrolyte. Here the high performance counter electrode can be fabricated with conducting polymer and using a polyelectrolyte can eliminate the use of liquid electrolyte that might leak out (Saranya et al., 2015 ).
Why are carbon nanotubes used in DSSC?
Because of their 1D structure and excellent charge collecting and conducting properties , carbon nanotubes are a natural choice as an additive to the photoactive layer in conventional DSSCs, to improve electron shuttling by offering a pathway for low-resistance transport to the anode. 86–89 In a study by Kamat et al ., SWCNTs were used as an electron-shuttling scaffold for the attachment of dye-sensitized TiO 2 nanoparticles, in a conventional DSSC arrangement. 86 In assembling these cells, well-dispersed SWCNTs in organic solvent were deposited electrophoretically on to an optically transparent electrode (OTE), followed by the application of TiO 2 paste over the film and incubation in a solution of ruthenium-based dye for sensitization. Steady state emission spectrum and emission decays showed that the presence of SWCNTs did not affect the charge injection process significantly. Nevertheless, the net effects showed an increase in the IPCE of 40% compared to the cell without carbon nanotubes. However, because of the shifted Fermi level of the semiconducting layer caused by the presence of SWCNTs, the net open circuit voltage was lowered, thus resulting in no overall increase in net efficiency. 86 Multiple similar studies in which pristine 88,89 and covalently modified 87 SWCNTs were incorporated into the TiO 2 mixture before deposition showed similar increases in short circuit current because of higher conductivity and possibly better light scattering. 87 Again, the open circuit voltages tended to suffer as a result of the effect on the Fermi level of the TiO 2 layer. 87–89 As it was shown that the pristine SWCNTs did not themselves interact directly with the dye molecules, 88,89 an alternative design was presented – in which SWCNTs were first covalently bound to a ruthenium-based dye via carboxylic acid groups. 87 In this case, the open circuit voltage actually showed an increase of up to 25% with the presence of these SWCNTs; however, the short circuit density showed a negligible increase. 87 The increased open circuit voltage is attributed to a negative shift of the conduction band edge caused by chemical modification of TiO 2 from reactive moieties on the dye-functionalized SWCNTs. 87 Despite promising results, the efficiency of DSSCs incorporating SWCNTs is still well below state of the art in DSSCs. 8,18,86–89 Possible improvements in efficiency will require a high degree of effective enrichment of semiconducting species, as well as separation or doping techniques, to carefully tune the band edge potentials for optimal performance.
What are the nanostructures of DSSC?
To increase the photovoltaic properties of the DSSCs, different ZnO nanostructures, such as microspheres, nanowires, nanorods, and their nanocomposites (nanowires/nanoparticles, nanorods/nanoparticles), as well as aggregate spheres, have been applied [2]. Moreover, ordered nanostructured TiO 2 nanorods and nanotubes are of great interest for DSSC application. In recent years, the modification of the electrochemical properties of TiO 2 through doping with transition metals, such as Zr, Nb, Ta, Ni, and W, or anions, such as N and F, has been the most promising method to improve DSSC efficiency.
What is the role of a counter electrode?
The counter electrode regenerates the electrolyte, and the most commonly one comprises platinum film prepared on a glass or silicon substrate. The main role of the electrolyte is to regenerate the dye and as an electrolyte medium it should display negligible vapor pressure, low viscosity, high dielectric properties, and a high boiling point [3]. Mostly I – /I 3– inorganic solvents, inorganic ionic liquids, and solid electrolytes are employed. Among them, the iodine electrolyte is the most common and provides high DSSC efficiency.
How Do Dye Sensitized Solar Cells Work?
The working mechanism of DSC differs greatly from other types of solar cells.
What does dye do in photosynthesis?
The dye uses energy from these photons to excite electrons in the cell, behaving like chlorophyll in photosynthesis.
What happens when a chemical electrolyte closes the circuit?
The chemical electrolyte in the cell closes the circuit so that the electrons are returned back to the dye.
Why is open circuit voltage high?
High open-circuit voltage because the organic p-type semiconductor has an energy level deeper than that of iodine
Do DSSCs degrade?
Compared to thin-film cells, DSSCs do not degrade in sunlight over time. Thus, dye sensitized solar cells last longer and require less frequent replacements. DSSCs are also mechanically strong, because they are made of lightweight materials and do not require special protection from rain or abrasive objects.
What are the advantages of dye sensitized solar cells?
One advantage of using dye sensitized solar cells is that DSSCs have a good depth in their nanostructure and they absorb the photons in sunlight well. The dyes used in the cells are effective in converting the absorbed photons into electrons. Generally, the peak power production efficiency of dye sensitized solar cells is about 11%, ...
What is the peak power production efficiency of dye sensitized solar cells?
Generally, the peak power production efficiency of dye sensitized solar cells is about 11%, making them suited to low-density applications. Although the effectiveness of DSSCs is less than many of the best thin film cells, the price-to-performance ratio attained through these solar cells is greater than other such cells.
Why does the efficiency of solar cells decrease?
As the temperature rises, other the silicon cells require protection covered by a glass box. These cells heat easily, therefore the efficiency is greatly reduced because of internal temperature. This does not happen in the DSSCs, because dye sensitized solar cells are made of only a thin layer of plastic. The heat easily radiates away, reducing the internal temperature. Due to the lowering of temperature, the efficiency of the solar cells is greater.
Why are DSSCs less expensive than other semiconductors?
Because of the lower manufacturing costs, DSSCs are less costly than other semiconductor cells. The dye used in dye sensitized solar cells absorbs scattered sunlight and fluorescent light. DSSCs also function in cloudy weather and low-light conditions without a great deal of impact on efficiency.
How are DSSCs made?
DSSCs are constructed on a semiconductor, which is designed so that the nanoparticles of titanium dioxide (TiO2) are coated with a light-sensitive dye and surrounded by electrolyte, which is inserted between another electrolyte and a cathode. The anode allows light to pass through because it is transparent. Sunlight goes through the transparent electrode into the dye layer, exciting electrons that then flow into the titanium dioxide. The electrolyte then carries the electrons back to the dye molecules. Dye sensitized solar cells split the two functions supplied by silicon in a traditional cell design. The energy gotten through this simple dye sensitive cell can be collected to drive electrical system loads.
Why does light pass through anode?
The anode allows light to pass through because it is transparent. Sunlight goes through the transparent electrode into the dye layer, exciting electrons that then flow into the titanium dioxide. The electrolyte then carries the electrons back to the dye molecules. Dye sensitized solar cells split the two functions supplied by silicon in ...
Why do solar headphones absorb sunlight?
These solar cells can absorb most of the available sunlight because they work at wider angles. Exeger Solar Headphone Bands. Dye sensitized solar cells do not degrade in sunlight over time as do other thin-film cells, making the cells last longer, and requiring less frequent replacements.
Why are DSCs better than silicon?
Another advantage that DSCs offer, due in part to their mechanical robustness, is the fact that they have higher efficiencies at higher temperatures than traditional solar cells typically do. DSCs are able to radiate heat away much more efficiently than traditional silicon cells and operate at lower internal temperatures, since they are usually built with only a thin layer of conductive plastic on the front layer, versus the more insulating glass box that is typically used for silicon solar cells.
What is a dye sensitized solar cell?
Dye-sensitized solar cells have become an incredible alternative to solid-state p-n- junction devices. With conversion efficiencies of over 11% having already been obtained, DSCs have a bright future in becoming a major contributor to renewable electricity generation, and with ongoing research, the efficiencies can only improve. Future research will focus on improving the short circuit current density by extending the light response of the sensitizers in the near-infrared spectral region, and substantial gains are expected from introducing ordered oxide mesostructures and controlling the interfacial charge recombination by manipulating the cell on the molecular level. With the work being done on DSCs, along with the already impressive numbers that these cells have put up, DSCs are a viable source of renewable energy for the future.
What are the advantages of DSCs?
Another advantage DSCs have over traditional solar cells is the fact that direct injection of a photon into the nanocrystalline metal oxide layer evades the possibility of an electron recombining with a hole. This circumvents the problem of no current being generated when recombination occurs. Whereas a hole is generated when an electron is excited across the bandgap in traditional cells, no hole is generated in a DSC when an electron is injected. Instead, only an extra electron is added. While it is theoretically and energetically possible for an electron to recombine with the dye, the rate of this happening is negligible compared to the rate at which electrons are supplied by the electrolyte. [6] Due to these favorable kinetics, DSCs will also work in low light conditions (i.e. cloudy skies and indirect sunlight). So little light is needed, that it has been suggested that DSCs be used indoors - light could be absorbed from the various lights that are usually used to illuminate indoor rooms. [7]
How does dye affect solar energy?
The dye used in dye-sensitized solar cells is extremely efficient at converting absorbed photons into free electrons in the titanium oxide layer. However, the current is limited to how many photons the dye can actually absorb—the photons that do get absorbed are the ones that ultimately produce the current.
What are DSCs used for?
Given the efficiency and low cost of materials needed to fabricate dye-sensitized solar cells, DSCs are an attractive replacement for existing technologies in "low-density" applications such as rooftop solar collectors, though the technology still has a way to go before it can be an attractive alternative for large-scale deployments as well. However, even a small increase in conversion efficiency for these new age solar cells could make them suitable for large-scale roles as well, as the efficiency of the cell would be worth the cost of utilizing more DSCs.
Why is solar energy important?
Background. In today's society, it is becoming ever important to find alternative sources of energy that are both cheap and efficient. Solar cells have become one of the most widely-researched methods of obtaining energy in "greener" ways than burning fossil fuels, etc.
When was the solar cell invented?
One of the new variants on the solar cell that is currently being researched is the dye-sensitized solar cell (DSC), which was invented by Michael Gratzel and Brian O'Regan in 1991. Where conventional systems take advantage of the semiconductor to absorb light and transport charge carriers, DSCs separate these two functions.
How to connect DSSC to multimeter?
After the assembled circuit is complete, place your cell under an indoor light source---or along a windowsill. ( Warning: Placing your solar cell directly under the sun without the proper protection will cause severe degradation. Do initial testing under light sources that do not emit UV radiation ). Record the maximum voltage and current produced by your solar cell. Multi ply these two figures to obtain the power output.
What do you need to make a solar cell?
For every solar cell you assemble, you will need an anode and a cathode. The anode will contain the dye and titanium dioxide molecules. Photons will excite the dye molecules' electrons, and the electrons will jump from the dye molecule to the titanium dioxide to the glass anode through diffusion.
What is the power of a DSSC?
Power is simply the voltage potential multiplied by the current. So, for example, if my DSSC produced 0.400 Volts and 250 microamps (0.000250A), the power output would be 0.1 milliwatt (0.0001 watt).
How long to soak annealed electrode in dye solution?
Regardless, soak the annealed electrode in your dye solution for ten minutes. (You should notice by then end of this period that the color of your glass plate has changed as dye molecules covalently bonded to the TiO2. This is the process known as sensitization.
How to insert electrolyte solution between two glass plates?
To insert the electrolyte solution between the two electrodes, apply the electrolyte liquid along an offset edge in between the two glass plates. Then, open and close the binder clips in an alternating fashion (one binder clip at a time, not both).
How to make anode?
So, to assemble your anode, you must: 1) Prepare a titanium dioxide solution. Slowly add 20mL of an acetic acid solution (0.1675 mL CH3COOH per 99.8225 mL water) to 12g of titanium dioxide powder. Slowly adding the acid, in addition to vigorously mixing the solution, will ensure a uniform paste.
How much energy does the Earth need to power the world?
Solar power is a particularly promising solution to the world's energy needs. The Earth annually absorbs nearly 4 million exajoules of solar energy, and it would require less than an hour of this total energy to power mankind for an entire year. There are many technologies to capture and convert the sun's energy.
What is a dye sensitive solar cell?
What is a Dye-Sensitized Solar Cell? Dye-sensitized solar cells (DSSC) are an efficient type of thin-film photovoltaic cell. Modern dye-sensitized solar cells, or Grätzel cells, are based on a concept invented in 1988 by Brian O'Regan and Michael Grätzel, but the concept dates back to the 1960s and 70s. DSSCs are easy to manufacture ...
What is a nanowire solar cell?
In 2004, researchers from the University of California at Santa Barbara described the performance and design of a zinc oxide nanowire-based dye-sensitized solar cell. The nanowires enable a direct electron conduction path between the conducting substrate and point of photogeneration and may offer enhanced electron transport compared to sintered nanoparticle films. The devices have a light harvesting efficiency below 10%, showing that present efficiencies and densities are enhanced by an order of magnitude by an increase in the nanowire surface area.
What materials are used in DSSCs?
Most of the materials used are low-cost, however a handful of more costly materials are necessary, such as ruthenium and platinum. There is a significant practical challenge involved in designing the liquid electrolyte for DSSCs, which must be able to remain in the liquid phase in all kinds of weather conditions.
What wavelengths are dyes sensitive to?
In 1999, newer versions were introduced with a higher frequency response that is efficient even at red and infra-red wavelengths. The dye used in these cells has a deep brown-black colour referred to as black dye, ...
How much sunlight does a dye sensitive solar panel convert to?
Presently, dye-sensitized solar panels convert about 11 – 12% of the sunlight striking them into electricity. The researchers are trying to increase the efficiency and make it comparable with silicon-based solar panels.
How is chlorophyll replaced in DSSCs?
In DSSCs, chlorophyll is replaced by a light absorbing dye, the molecules of which are excited into a higher energetic state by incoming light. This energy is collected by a structure of electrolytes and catalysts, much like the surrounding structure of a leaf in photosynthesis.
What is Will's degree?
Will has a B.Sc. in Chemistry from the University of Durham, and a M.Sc. in Green Chemistry from the University of York. Naturally, Will is our resident Chemistry expert but, a love of science and the internet makes Will the all-rounder of the team. In his spare time Will likes to play the drums, cook and brew cider.