Education and Solar conversion (original) (raw)
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A LOW-COST SOLAR CELL BASED ON DYE-SENSITIZED NC-RUTILE TIO2 FILMS
This work shows a simple technology for fabricating TiO2 solar cells using inexpensive, available materials. It depends completely on the rutile shape of TiO2 only, which is simply fabricated for preparation of nanocrystalline (nc)-TiO2 dye-sensitized solar cell (DSC). Nc-rutile TiO2 is produced by hydrolysis of TiCl4, and it is separated by a simple manual method. In this paper, we studied heat-treatment conditions of films in air by varying several conditions (annealing temperature, annealing time, and density of the film). Sensitization of films by using several dyes (blackberries, N3, and Rhodamine 6G) is done to form a photo-electrode. In addition, a soft pencil lead is used to apply a carbon film on a conductive glass to form the counter-electrode. On the other hand, NaI/I2 is used as a mediator electrode to create recycling for the electron transfer in the nc-DSC. In addition, variation of the electrolyte media by using several solvents (acetonitrile and propylene carbonate) is also considered. The particle size of nc-rutile TiO2 is directly proportional with annealing temperature and inversely proportional with annealing time. Photocurrent and photovoltage of nc- DSC depends on several parameters such as density of TiO2 film, type of dye, and the solvent used with the electrolyte. At AM0 with optimum conditions, the cell can produce a photocurrent of 5 μA/cm2 and a photovoltage of 0.8 V.
Hand made solar cells from chlorophyll for teaching in high school energy education
International Journal of Ambient Energy, 2020
High school students show more motivation to learn new concepts when these are taken from activities that mimic real life. Then, we report an easy methodology based on the fabrication of handmade solar cells to produce clean energy from chlorophyll a (chl-a) extracted from the leaves of Diacol Capiro potato. Our findings show that there is no proportionality between the chl-a concentration and the output voltage. The results also indicated that nickel-silver electrodes were the most efficient among other tested electrode pairs, yielding a maximum voltage value of 1.006 V from an individual cell. Therefore, a low-cost natural dye as chlorophyll can be used as light-harvesting material. As a result, 90% of the students learned basic techniques and applications of visible light for characterizations and 85% understood the electric potential in an electrochemical cell.
Simple photovoltaic cells for exploring solar energy concepts
Low-efficiency solar cells for educational purposes can be simply made in school or home environments using wet-chemistry techniques and readily available chemicals of generally low toxicity. Instructions are given for making solar cells based on the heterojunctions Cu/Cu 2 O, Cu 2 O/ZnO and Cu 2 S/ZnO, together with a modified Grätzel cell.
9. Assembly of Dye-Sensitized Solar Cell using the Stem and Grain
Red anthocyanins from sample A (stem of sorghum bicolor) and sample B (grains of sorghum bicolor) were employed as TiO 2 dye -sensitizers. Solar cells sensitized by the extracts of sample A achieved the following for outdoor measurement; I SC = 0.0023mA/cm 2 , V OC = 0.0022V, P max = 3.666mV/cm 2 , FF = 0.7212, η= 1.7554 and for sample B outdoor measurement FF = 0.7961, I sc = 0.00178mA/cm 2 , V oc = 0.0014V, P max = 4.96 x 10 -6 mw/cm 2 and η = 4.221 under the illumination of solar energy 4.7x10 -3 W/cm 2 respectively. The indoor measurement values for the same dyes sensitized cells determined for sample A are I SC =0.0182mA/cm 2 , V OC = 0.004 V; P max = 3.299 x 10 -7 mW/cm 2 , FF = 0.4512, η =0.15 and sample B achieved I SC = 0.01378 mA/cm 2 ; V OC = 0.005 V, P max = 3.5 x 10 -7 mW/cm 2 , FF = 0.5511and η =0.18 respectively. The results show that Sample B (indoor and outdoor measurement) has higher efficiency than sample A. This is due to the constituent of the extract .Sample A and B show a successful conversion of visible light into electricity by using natural dyes as band-gap semiconductor sensitizer in dye-sensitized solar cells .This can be use in large scale to reduce power and energy requirements for future industry designs.
Light harvesting and electron injection
Dye-sensitized solar cells (DSSCs) based on nanocrystalline semiconductors such as TiO 2 are of great interest as an alternative to the conventional solar cells because of their high performance, low-cost production, and environmental advantages. The DSSCs consist of dye molecule coated wide bandgap semiconductor layer, electrolyte, and transparent conducting oxide (TCO) film. When the DSSCs are exposed to solar light, an incident photon creates a bound electron-hole pair in dye sensitizers. Electrons then flow into the oxide nanoparticle anode due to a difference in the energy levels. On the other hand, holes move to the counter electrode through sequential redox reactions in the electrolyte. Therefore, the cell performance is influenced by parameters such as the morphology and optical properties of nanocrystalline oxide films, the electrochemical characteristics of redox electrolytes, and the photochemical properties of molecular sensitizers. In this article, we review the major components of DSSCs such as the oxide semiconductor film, sensitizing dyes, electrolytes, and TCO and discuss their progress to maximize light harvesting and charge injection efficacy. Their electrical, optical, and chemical properties are well correlated to optimize the light harvesting and charge injection of DSSCs. We have also shown recent efforts to improve the energy conversion efficiency, long term stability, sustainability and affordability by modifying or revolutionizing the components of DSSCs. This includes a prospect on the potential commercialization of DSSCs.
Renewable Energy, 2010
Simple dye-sensitized solar cells were developed using blackboard chalk as a substrate for mixed ZnO and SnO 2 films that were sensitized with Mercurochrome (Merbromine) dye. Graphite pencil ''leads'' were used as counter electrodes for the cells and the electrolyte consisted of an aqueous solution of iodine and potassium iodide that was gelled with a disinfectant containing quaternary ammonium compounds and cyanoacrylate adhesive (Superglue Ò). The open circuit potential of constructed cells was typically 0.50-0.64 V and the short circuit current varied between 0.5 and 2.0 mA cm À2. The cells were developed as an educational resource that could be simply and safely constructed in a home or school environment with readily accessible materials.