Sains Malaysiana 40(3)(2011): 203–208
Influence
of PANI Additions on Methanol Sensing Properties of ZnO Thin Films
(Pengaruh Penambahan PANI ke atas Sifat Pengesanan Wap Metanol oleh Filem Nipis ZnO)
Mohammad Hafizuddin Haji Jumali*, Norhashimah Ramli, Izura Izzuddin & Muhammad Yahaya
School of Applied Physics, Faculty of Science & Technology
Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor D.E., Malaysia
Muhamad Mat Salleh
Institute of Microengineering and Nanoelectronic (IMEN)
Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor D.E., Malaysia
Diserahkan: 15 Mei 2010 / Diterima: 3 September
2010
ABSTRACT
The influence of PANI additions on methanol sensing properties of ZnO thin films at room temperature had been investigated. Commercial polyaniline powder (PANI) was mixed into 3 mL ZnO solution in five different
weight percentages namely 1.25, 2.50, 3.75, 5.00 and 6.25% to obtain ZnO/PANI composite solutions. These
solutions were spin coated onto glass substrate to form thin films. Microstructural studies by FESEM indicated
that ZnO/PANI films showed porous
structures with nanosize grains. The thickness of the
film increased from 55 to 256 nm, proportionate to increment of PANI.
The presence of 2 adsorption peaks at ~310 and ~610 nm in UV-Vis
spectrum proved that addition of PANI has modified the
adsorption peak of ZnO film. Methanol vapour detection showed that addition of PANI into ZnO dramatically improved the sensing properties of
the sensor. The sensors also exhibited good repeatability and reversibility.
Sensor with the amount of PANI of 3.75 wt% exhibited the highest
sensitivity with response and recovery time was about 10 and 80 s,
respectively. The possible sensing mechanism of the sensor was also discussed
in this article.
Keywords: Gas sensor;
methanol vapour; microstructure; UV-Vis
analysis; ZnO/PANI thin film
ABSTRAK
Pengaruh penambahan PANI ke atas sifat pengesanan wap metanol oleh filem nipis ZnO telah dikaji pada suhu bilik. Lima amaun serbuk polianilina (PANI) dengan peratusan berat 1.25, 2.50,
3.75, 5.00 dan 6.25% dicampurkan ke dalam 3 mL larutan ZnO untuk menghasilkan larutan komposit ZnO/PANI. Larutan ini kemudiannya dimendapkan ke atas substrat kaca menggunakan teknik salutan berputar untuk membentuk filem nipis. Analisis mikrostruktur melalui FESEM menunjukkan filem nipis komposit ZnO/PANI adalah poros dengan saiz butiran yang terhasil berskala nanometer. Nilai ketebalan filem yang diperolehi meningkat daripada 55 sehingga 256 nm setara dengan penambahan amaun PANI. Analisis UV-Vis mengesahkan kehadiran PANI yang mengubah puncak penyerapan filem ZnO dengan penghasilan 2 puncak penyerapan pada panjang gelombang ~310 dan ~610 nm. Ujian pengesanan sensor terhadap wap metanol menunjukkan kehadiran PANI telah meningkat sifat pengesanan sensor secara mendadak dengan menonjolkan sifat kebolehulangan dan kebolehbalikan yang baik. Diperoleh, sensor dengan amaun PANI sebanyak 3.75 wt% mempamerkan kepekaan tertinggi dengan masa tindak balas dan pemulihan masing-masing adalah 10 dan 80 s. Andaian mekanisme pengesanan sensor dibincangkan dalam artikel ini.
Kata kunci: Analisis UV-Vis; filem nipis ZnO/PANI; mikrostruktur; sensor gas; wap methanol
RUJUKAN
Agbor, N.E., Petty, M.C.
& Monkman, A.P. 1995. Polyaniline thin
films for gas sensing. Journal of Sensors and Actuators B 28:
173-179.
Arshak, K., Moore, E., Cunniffe, C., Nicholson, M. & Arshak,
A. 2007. Preparation and characterisation of ZnFe2O4/ZnO polymer nanocomposite sensors for the detection of alcohol vapours. Journal of Superlattices and Microstructures 42: 479-488.
Choudhury, A. 2009. Polyaniline/silver nanocomposites:
Dielectric properties and ethanol vapour sensitivity. Journal of Sensors and Actuators B 138: 318-325.
Geng, L., Zhao, Y.,
Huang, X., Wang, S., Zhang, S. & Wu. S. 2007. Characterization and gas
sensitivity study of polyaniline/SnO2 hybrid material prepared by hydrothermal route. Journal of Sensors and
Actuators B 120: 568-572.
Geng, L., Zhao, Y.,
Huang, X., Wang, S., Zhang, S., Huang, W. & Wu, S. 2006. The preparation
and gas sensitivity study of polypyrrole/zinc oxide. Journal
of Synthetic Metals 156: 1078-1082.
Haji Jumali, M.H., Izzuddin, I., Ramli, N., Mat Salleh, M. & Yahaya, M. 2009. Comparative studies
on microstructural and gas sensing performance of TiO2 and TiO2-PANI nanocomposite thin films. Solid State Science and Technology 17: 126-131.
Han,
C.H., Han, S.D. & Khatkar, S.P. 2006. Enhancement
of H2-sensing properties of F-doped SnO2 sensor by surface
modification with SiO2. Journal of Sensors 6: 492-502.
Hooker, S.A. 2002.
Nanotechnology advantages applied to gas sensor development. Proceedings
of the 2002 Nanoparticles Conference.
Hosono, K., Matsubara,
I., Murayama, N., Woosuck, S. & Izu, N. 2005. Synthesis of Polypyrrole/MoO3 hybrid thin films and their volatile organic compound gas sensing properties. Journal
of Chemistry Material 17: 349-354.
Kaushik, A., Khan, R.,
Gupta, V., Malhotra, B.D., Ahmad, S. & Singh,
S.P. 2009. Hybrid cross-linked polyaniline-WO3 nanocomposite thin film for NOx gas sensing. Journal of Nanoscience and Nanotechnology 9: 1792-1796.
Matsuguchi, M., Io, J.,
Sugiyama, G. & Sakai, Y. 2002. Effect of NH3 gas on the
electrical conductivity of polyaniline blend films. Journal of Synthetic Metals 128: 15-19.
Nardis, S., Monti, D., Natable, C.D., Amico, A.D., Siciliano, P., Forleo, A., Epifani, M., Taurino, A., Rella, R. & Paolesse, R. 2004. Preparation and Characterization of
Cobalt Porphyrin modified tin dioxide thin films for
sensor application. Journal of Sensors and Actuator B 103: 339-343.
Ram,
M.K. & Malhotra, B.D. 1996. Preparation
and characterization of Langmuir-Blodgett films of polyemeraldine base. Journal of Polymer 37: 4809-4813.
Sahay, P.P. & Nath, R.K. 2008. Al-doped ZnO thin films as methanol sensors. Journal of
Sensors and Actuators B: Chemical 134: 654-659.
Shukla, S., Agarwal, R., Cho, H.J., Seal, S., Ludwig, L. & Parish,
C. 2005. Effect of ultraviolet radiation exposure on room-temperature hydrogen
sensitivity of nanocrystalline doped tin oxide sensor
incorporated into microelectromechanical system
device. Journal of Applied Physics 97: 1-13.
Tai,
H., Jiang, Y., Xie, G., Yu, J. & Chen, X. 2007. Fabrication and
gas sensitivity of polyaniline-titanium dioxide nanocomposite thin film. Journal of Sensors and
Actuators B 125: 644-650.
*Pengarang untuk surat-menyurat; e-mail: hafizhj@ukm.my
|