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
Received: 15 May 2010 / Accepted: 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
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*Corresponding
author; e-mail: hafizhj@ukm.my
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