Dye-sensitized solar cell using natural dyes extracted from Bougainvillea and bottle Brush flower

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1 Dye-sensitized solar cell using natural dyes extracted from Bougainvillea and bottle Brush flower Mr.Muhammed Thanzeel M.A #1, Mr. Paulose Paulose #2,Mr. Giphin George $3, Mr.Jimmy John *4 # M.Tech. Student, Govt. Model engineering college, Mechanical Engineering (Energy Management),CUSAT, Kochi, Kerala, India. $ Assistant professor, Cochin Institute of Science And Technology, Muvattupuzha, kerala,india * Assistant professor, Govt. Model engineering college,thrikkakara, Kochi, Kerala,India Abstract:- Dye-sensitized solar cells (DSSCs) were fabricated using dyes extracted from Bougainvillea and Bottle brush flower. The energy conversion efficiencies ( of Bougainvillea and Bottle brush flower found out to be 0.31% and0.23% respectively. This phenomenon is mainly due to the better interaction between the carbonyl and hydroxyl s of anthocyanin molecule on dye extracts and the surface of TiO2 porous film. The absorption spectrums of both the dyes were also discussed in this paper. Due to its low cost, simple preparation technique and easy availability the dye sensitized solar cells are found out to be really promising. Keywords Solar energy, Energy management, Low cost solar cell, Natural dyes. I.INTRODUCTION Dye-sensitized solar cells (DSSC) are devices for the conversion of light to electric energy by mimicking photosynthesis of plants. Gratzel and O Regan(1991)invented a prototype of DSSC cell which is much eco friendlier as well as cost effective[1].the conversion of light energy to electrical energy takes place due to the excitation of electrons from photo anode to counter electrode. A DSSC mainly consist of an nano crystalline titaniumdioxide(tio 2 )electrode,which is impregnated on dyein an transparent conducting oxide (TCO), a platinum or graphite coated counter electrode, and an electrolyte solution placed between the two electrodes based on the iodide/iodine redox couple (I - /I - 3)[6].The performance of the DSSC is mainly depend on the association of TiO 2 and the absorption spectrum of the dyes used for sensitizer[3].the sensitization is mainly due to anthocyanins, which is a natural phenolic compound [10].The main advantages of these cells while comparing with the conventional PV cells are better performance in low light as well as with the diffused radiation, its low cost and eco friendlier. In this paper the DSSCs where prepared by using dyes extracted from Bougainvillea and bottle brush flowers. The efficiencies and fill factor between two dyes are discussed. Photoelectrical and optical properties of DSSC sensitized with natural dyes were also discussed. 2. EXPERIMENTAL 2.1 Materials and methods The DSSC mainly consist of an transparent conductive oxide (TCO) coated glass 2 mm thick glass substrate with fluorine doped tin oxide coating on one side (2.5x2.5 cm 2 ). We have used nanocrystalline TiO 2 (Sigma-Aldrich, nanopowder, <25 nm particle size, MW g/mol, MP at C) and Potassium iodide solution (0.5M KI+ 0.05M I 2 in acetonitrile solvent) as electrolyte. The Counter electrode was coated with graphite which acts as catalyst and the dyes are extracted from the two flowers that I have chosen. 2.2 Preparation of natural dye sensitizers The natural dyes which are used to make the sensitizer were extracted from Bougainvillea and ISSN: Page 43

2 bottle brush flowers. The petals of two flowers are taken and grinded separately using a grinder for easy extraction of colour. We took aconical flasks filled with 100 ml distilled water and the grinded petals were put inside that conical flask and stirred well.then we added1 ml of HCL to the solutionand heated up to 100 o C.Then the solution Stirred properly until colour change occurs and keep the vessel up to minutes and dye was extracted using a filter paper. factor (FF) were calculated using the following relations. FF = V max I max / V oc I sc (1) =I sc V oc FF / P in (2) Where P in is the power of incident light 2.3 Preparation of dye-sensitized solar cells A TiO 2 photo anode was prepared by TiO 2 with diluted nitric acid. We have taken 10 ml of dilute nitric acid and added gradually to 0.6 g Titanium Dioxide[3].It was stirred and grinded with a mortar and pestle until the solution becomes smooth and lump-free. We had determined the conductive side using a multi-meter and the conductive sides were masked with a masking tape.a uniform, thin layer of TiO 2 was deposited across the unmasked portion of the slide by drawing a stir-rod along the slide Fig.1.The slide was allowed to dry for a few minutes and tape was removed and then the substrate were sintered at 450 o C for 30 min using muffle furnace. Fig 1After application of TiO 2 The sintered TiO 2 layer is impregnated with natural dyes for 4 hours and rinse with absolute ethanol. After 4 hours the catalyst (graphite) coated counter electrode was placed on the top so that the conductive side of the counter electrode faces the TiO 2 film.we prepared the iodide electrolyte solution (0.5M potassium iodide mixed with 0.05M iodine in acetonitrile solvent) and placed at the edges of the plates[3].two binder clips were used to hold the electrodes togetherfig Characterization and measurement We recorded the absorption spectra of dye solutions and dyes adsorbed on TiO2 surface using a UV VIS Spectrophotometer and the Solar energy conversion efficiency (I-V curve) was measured using a digital Keithley source meter under stimulated sunlight( AM 1.5, 100 mwcm -2 condition).the short circuit current(i SC ) and open circuit voltage (V OC) were calculated using the I-V curve. The efficiency and fill Fig2 Final DSSCs Bougainvillea(right) and bottle brush flower (left) 3. RESULT AND DISCUSSION 3.1 Absorption of natural dyes The absorption spectrum of Bougainvillea and bottle brush flowers was obtained using Ultraviolet-visible spectroscopy (UV-Vis). Fig.3 shows the absorption spectra of both the flowers. The wavelength range of both the spectrum is in between 400 to 800 nm. After analyzing the spectrum we found out that ISSN: Page 44

3 International Journal of Engineering Trends and Technology (IJETT) Volume 33 Number 1- March 2016 Bougainvillea shows a good absorption level in between 400 to 600 nm with peak absorption at 520 nm. When it comes to bottle brush flower, it has a good absorption level between 400 to 600 nm with peak absorption at 510 nm. TiO 2 which makes the electron transfer from anthocyanin molecules to the conduction band of TiO %T Fig 3UV-Vis absorption graph of Bougainvillea (A)and bottle brush flower(b) 4000 Bonganvilla Fig 4FTIR spectrum of bottle Bougainville Table 1 Functional of Bougainvillea /cm FT-IR spectrum of Bougainvillea flower is showed in the Fig.4.While analyzing the FT-IR spectrum of Bougainvillea there is broad absorption spectra between cm -1 with a peak value of cm -1 corresponding to the vibration of O-H (Carboxylic ). There is a sharp absorption between cm -1 with a peak value of cm -1 due to vibration of C=O (Carbonyls)Table1. Fig.5 Represents the FT- IR spectra of bottle brush flower. When we analyze the spectrum of bottle brush flower, there is a broader absorption spectra between cm -1 with a peak value of cm -1 corresponding to the vibration of O-H (Carboxylic ). There is a sharp absorption between cm -1 and cm -1 with peak values of cm -1 and cm -1 is due to the vibrations of C=O (Carbonyls) and C-Br (Alkyl halides)table.2. By analyzing the FT-IR spectrum and the UV-Vis we can infer that the sensitization of the wide band gap is mainly due to anthocyanins[3]. The anthocyanins are present in roots, leaves, flowers etc. The carboxyl and hydroxyl present in the anthocyanin molecules can from a good bond with Frequency Peak value bond O-H C=O 100 %T Bottle brush Fig.5FTIR spectrum of bottle brush flower Table 2 Functional of Bottle brush flower Functional Carboxylic Carbonyls /cm ISSN: Page 45

4 Frequency Peak value bond O-H C=O C-Br Functional Carboxylic Carbonyls Alkyl halides Table 3 Photoelectric parameter of DSSC Dyes I SC V OC FF h (%) (ma) (mv) Bougainvillea Bottle brush flower Photoelectrical properties of DSCs sensitized with natural dyes The photoelectrical properties of the DSSCs using natural dyes are found out by measuring the currentvoltage curve under the irradiation of 100mWcm -2. The performance of Dyes as sensitizers was evaluated using short circuit current (I SC ), open circuit voltage (V OC ), Fill factor (FF) and energy conversion efficiency (. The typical I-V curve of a DSSC is shown infig.6 and the photoelectric parameters are shown in the Table.3. From the Fig.6the values of short-circuit current (I SC ) opencircuit voltage (V OC ) of the DSSC made by using Bougainvillea can be obtained directly, which is 1.41mA and V, respectively. The maximum power of the DSSC confirmed based on P max = I Vof the point P on the Fig.6which is 312.5µW. The fill factor and efficiency ( ) of the Bougainvillea is 0.56 and 0.31% respectively. While the bottle brush flower is having fill factor of 0.51 and the efficiency ( is found out to be 0.23%Table.3. So while we comparing both Bougainvillea and the Bottle brush flower, the bougainvillea flower shows better fill factor as well as the energy conversion efficiency than that of Bottle brush flower. 3. CONCLUSION Natural dyes were extracted from Bougainvillea and Bottle brush flowers. Using the natural dyes extracts as photo sensitizers, dye-sensitized solar cells (DSC) were assembled and the I SC, V OC, FF, Efficiency values of Bougainvillea found out to be1.41ma, 0.392V,0.56,0.31%respectively. But in the case of Bottle brush flower the values are 1.21mA, 0.380V, 0.51, 0.23%. In conclusion, the Bougainvillea extract has higher photosensitized performance as compared to the pea blue extract. This is due to the better charge transfer between Bougainvillea dye molecule and the TiO 2 surface which is related to a dye structure. Because of the simple preparation technique, low cost and widely available natural dye as an alternative sensitizer for dye-sensitized solar cell is promising REFERENCES Fig.6 Current voltage curve of Bougainville DSSC [1] Sancun Hao, Jihuai Wu &Yunfang Huang, Jianming Lin Natural dyes as photosensitizers for dye-sensitized solar cell, SolarEnergy 80 (2006) [2]Eiji Yamazaki, Masaki Murayama, Naomi Nishikawa, Noritsugu Hashimoto,Masashi Shoyama, Osamu Kurita, Utilization of natural carotenoids as photosensitizersfor dyesensitized solar cells,solar Energy 81 (2007) [3]Khwanchit Wongcharee,Vissanu Meeyoo,Sumaeth Chavadej. Dye-sensitized solar cell using natural dyes extracted from rosella andblue pea flowers,solar Energy Materials & Solar Cells 91 (2007) [4] Monishka Rita Narayan, Review: Dye sensitized solar cells based on natural photosensitizers,renewable and Sustainable Energy Reviews 16 (2012) ISSN: Page 46

5 [5] Norasikin A. Ludin, A.M. Al-Alwani Mahmoud, Abu Bakar Mohamad,Abd. Amir H. Kadhum, Kamaruzzaman Sopian,Nor Shazlinah Abdul Karim, Review on the development of natural dye photosensitizer for dye-sensitized solar cells, Renewable and Sustainable Energy Reviews 31 (2014) [6]A. Torchani, S. Saadaoui, R. Gharbi, M. Fathallah, Sensitized solar cells based on natural dyes,current Applied Physics 15 (2015) 307e312 [7] Riyaz Ahmad Mohamed Ali and Nafarizal Nayan. Fabrication and analysis of dye-sensitized solar cell using natural dye extracted from dragon fruit, International Journal of Integrated Engineering (Issue on Electrical and Electronic Engineering) [8]Huizhi Zhou, Liqiong Wu, Yurong Gao, Tingli Ma, Dyesensitized solar cells using 20 natural dyes as sensitizers,journal of Photochemistry and Photobiology A: Chemistry 219 (2011) ISSN: Page 47