Synthesis of Sol-gel derived ZnO nanopowder for Photovoltaic applications

Synthesis of Sol-gel derived ZnO nanopowder for Photovoltaic applications

Sunita Sharmaa,*, Avinashi Kapoorb, D.Kanjilalc and Bulkeshd

a Materials Science Group, Inter-University Accelerator Centre, New Delhi India

*Present Address: department of Applied Science and Humanities, ITM University, Gurgaon, India bDepartment of Electronic Science University of Delhi, South Campus, New Delhi, India dDepartment of Applied Physics, Guru Jambheshwar University of Science and Technology, Hisar E-mail : sunphotonics@gmail.com

Abstract

In the present work, ZnO nanoparticles are synthesised by using Sol-gel technique. The morphological (TEM and XRD) and optical studies (FTIR) of the grown ZnO nanparticles are made. The average particle size of the grown ZnO nanoparticles are made. The average particle size of the grown ZnO nanoparticles is about 40nm which is suitable to be used as transparent conducting oxide layer in dye sensitised solar cells (DSSC).

1. Introduction

   ZnO is considered as a good candidate for transparent conducting electrodes in solar cells because it is transparent to the visible light. It is also considered as a prime candidate for light-emitting devices such as blue LED and Lasers due to its large exciton binding energy. Due to such large exciton binding energy, the excitons remain dominant in optical processes even at room temperature. Due to its vast industrial applications such as electrophotography, electroluminescence phosphorus, pigment in paints, flux in ceramic glazes, filler for rubber products, coatings for paper, sunscreens, medicines and cosmetics, ZnO is attracting considerable attention in powder as well as thin film form.[1-3] Its resistance to radiation damages also makes it useful for space applications. It is also used as transparent conducting oxide layer in Dye Sensitized Solar Cells (DSSCs). DSSCs are among the most promising candidates for alternative renewable energy devices, having the advantages of low cost and large scale processing [4-12]. In the present work, ZnO nanoparticles are grown by cost- effective technique i.e. sol-gel.

2. Experimental

   All the reagents used were of analytical grade. ZnO nanopowder was prepared by dissolving 0.2M Zinc acetate dihydrate [Zn(CH3COO)2.2H2O] in methanol at room temperature and then mixing this solution ultrasonically at 25 0C for 2h. Clear and transparent sol with no precipitate and turbidity was obtained. 0.02 M of NaOH was then added in the sol and stirred ultrasonically for 60 min. The sol was kept undisturbed till white precipitates were seen in

   the sol. After precipitation, the precipitates were filtered and washed with the excess methanol to remove starting material. Precipitates were than dried at 800C for 15 min on hot plate.

3. Results and Discussion

   TEM image of the sol-gel derived nanoparticles are shown in Fig. 1. It can be seen from the TEM image that the average particle size is ~ 40 nm.

   Fig. 1 TEM image of the sol-gel derived ZnO nanoparticles

   The XRD pattern of the grown nanoparticles is shown in Fig. 2 and it shows crystalline nature with peaks lying at 31.7500 <100>, 34.4400 <002>, 36.2520 <101>, 47.5430

   <102>, 56.5550 <110>, 62.8700 <103>, 66.3880 <200>,

   67.9170 <112>, 69.0570 <201>, 72.6100 <004>, 76.950

   <202>, 81.4050 <104>, and 89.6300 <203>. These peak

   positions coincide with JCPDS card no. 36-1451 for ZnO powder.

   101

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   Counts

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   ZnO nanopowder

   1. Saxena V.,Veerender P., Chauhan A. K., Jha P., Aswal D. K., Gupta S. K., Applied Physics Letters, AIP, 100 (2012) 133303(3 pages).

      112

   2. Nam J.G., Park Y.J., Bum Sung Kim B.S., Lee J.S. Enhancement of the efficiency of dye-sensitized solar cell by utilizing carbon nanotube counter electrode Scripta Materialia 62, (2010) 148- 150.

      100

      110

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      10 20 30 40 50 60 70 80 90

      2theta (degree)

      Fig. 2

   3. Gratzel M., Conversion of sunlight to electric power by nanocrystalline dye-sensitized solar cellsJ. Photochem. Photobiol.AChem. Elsevier,164(1-3), 3-14 (2004).

   4. Hirata N., Lagref J.J., Palomares E.J., Durrant J.R., Nazeeruddin

      XRD pattern of ZnO nanoparticles synthesized via sol-gel

      90

      M.K., Gra¨tzel M., Censo D.D., Supramolecular Control of Charge-Transfer Dynamics on Dye-sensitized Nanocrystalline TiO2 Films Chem. Eur.J. Wiley,10(3), (2004) 595-602.

      80

      Transmittance (a.u.)

      70

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      40 Zn-O

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      -OH

      -OH

   5. Ito S., Zakeeruddin S.M., Baker R.H., Liska P., Charvet R., Comte P., Nazeeruddin M.K., Pechy P., Takata M., Miura H., Uchida S., Gra¨tzel M., High efficiency organic dye sensitised solar cells controlled by nanocrystalline TiO2 electrode thickness, Adv. Mater.,Wiley, 18, (2006) 1202-1205.

      route

      10

      500 1000 1500 2000 2500 3000 3500

      Wavenumber (cm-1 )

   6. Nazeeruddin M.K., Pechy P., Renouard T., Zakeeruddin S.M., Humphry-Baker R., Comte P., Liska P., Cevey L., Costa E., Shklover V., Spiccia L., Deacon G.B., Bignozzi C.A., Gratzel M.

      Fig. 3 FTIR spectra of sol-gel derived ZnO nanoparticles

      FTIR spectra of the grown ZnO nanoparticles is shown in Fig.3. The valley at 700 nm shows the Zn-O bond. It confirms the successful growth of ZnO nanoparticles.

4. Conclusion

   ZnO nanoparticles are grown by sol-gel technique. The grown material is highly crystalline in nature and has average particle size ~40 nm. It is a potential material to be used as transparent conducting oxide layer to be used in DSSC.All manuscripts must be in English. These guidelines include complete descriptions of the fonts, spacing, and related information for producing your proceedings manuscripts.

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