J. Pure App. Chem. Res., 2014, 3 (2), 70‐75 7 June 2014 X The journal homepage www.jpacr.ub.ac.id ISSN : 2302 ‐ 4690 70 Study of Suspension Concentration Effect to The Electrical Resistance of Zinc Sulphophthalocyanine (ZnPcS n ) Thin Film as Prototype of Ozone Detector Dhesy Galuh Ratnawati 1* , Masruroh 2 , Rachmat Triandi Tjahjanto 1 1 Departement of Chemistry, Faculty of Science, Brawijaya University, Jl. Veteran 65145, Malang, East Java, Indonesia 2 Departement of Physics, Faculty of Science, Brawijaya University, Jl. Veteran 65145, Malang, East Java, Indonesia *Corresponding author: dhesy.galuh@yahoo.com Received 2 December 2013; Accepted 10 April 2014; Published online for edition May-August 2014 ABSTRACT We have studied the fabrication of zinc sulphophthalocyanine (ZnPcS n ) thin film as prototype of ozone detector. The aim of this research is to find the relation between the electrical resistance of ZnPcS n thin film and the ZnPcS n suspension concentration. The thin film of ZnPcS n was deposited on Printed Circuit Board (PCB) substrate by using spin coating method, then, annealed at temperature of 100 o C. The resistance of ZnPcS n thin film was measured as it was exposed with ozone, synthesized from fresh air, for 60 min continuously. The electrical measurement was conducted twice for each point of data. The result of this research shows that the electrical resistance of ZnPcS n thin film decreases during the ozone exposure, and, it can be concluded that as the concentration of ZnPcS n suspension concentration increase, more amount of ozone can be adsorbed by thin film. Keywords: zinc sulphophthalocyanine (ZnPcS n ) thin film, PCB substrate, suspension concentration, ozone, electrical resistance INTRODUCTION The general method to detect ozone is the sensor-based method, for example, solid electrolyte, wet electrochemical sensor and metal oxides sensor. The solid electrolyte sensor is used to control the exhaust gas by using electrolyte cell plate insulated by two electrodes [1] which is operated only at high temperature [2]. The wet electrochemical sensor is gas sensor also use an electrochemical principle for gas detection. This method exhibits high sensitivity towards gases and requires less cost but with complexity of the maintenance [3]. Metal oxides sensor such as SnO 2 , In 2 O 3 dan WO 3 , doped or undoped, can be used to detect CO, NO x and O 3 gases [2]. This sensor needs catalyst and high temperature to work [4]. Another method that used for gas detection is utilizing organic semiconductors as sensors, one of them is metal phthalocyanine thin film. We studied the fabrication of zinc phthalocyanine (ZnPc) thin film on a commercially available circuit board. ZnPc is relatively cheap and having a good sensitivity toward gases up to ppb level [5]. In addition, modified ZnPc has been widely developed as oxidizing gas sensor like NO 2 [6], but the usage as ozone sensor was not reported yet. Therefore, in this research we developed thin films of modified ZnPc as ozone detector.