© December 2021| IJIRT | Volume 8 Issue 7 | ISSN: 2349-6002 IJIRT 153360 INTERNATIONAL JOURNAL OF INNOVATIVE RESEARCH IN TECHNOLOGY 563 TiO 2 Thin Films: A Review Amol P Zerwal 1 , Rajendra S Khadayate 2 , Neha N Malpure 3 , Chetan K Kasar 4 , Dipak M Marathe 5 , Shriram T Suryawanshi 6 1,2,3 G.D.M. Arts, K.R.N Commerce & M.D. Science, Jamner, Dist. Jalgaon, Maharashtra, India 4 Chatrapati Shivaji Jr Science College, Jalgaon, Maharashtra, India 5 S R N D Arts, Commerce and Science College, Bhadgaon, Dist. Jalgaon, Maharashtra, India 6 S S M M Arts, Science and Commerce College, Pachora, Dist. Jalgaon Maharashtra, India Abstract - Oxides of materials have huge applications in near about all developments and technologies. The proper synthesis of oxides with different doping, it is widely used for various purposes. In this review article, synthesis of TiO2 by sol gel method and different methods for deposition of thin films is explained because; sol gel method is found convenient, suitable, simple, low- cost method. Review said that Titanium dioxide (TiO2) is found the vast applicable material. It has lots of application. TiO2 itself or with doping with proper material it used as a photo sensor, humidity sensor, ethanol sensor, organic vapour sensor, environmental chemical species sensor, pH sensor etc. The different properties of TiO2 are studied and explained in this review article. Index Terms - Synthesis, Deposition, Thin Films, Sol - gel, spin coating, Sensing, Dopant, etc. 1.INTRODUCTION Since ancient time, our ancestor has started the journey of research. The latest technology in science is nothing but the need of human being. As per the need, we developed by using the materials on the Earth in proper manner and proper proportion. We use all materials in bulk quantity, but before the use we must know the properties of smallest unit. To know the property, structure etc of smallest form of material on their nano scale we must know the different thin or thick film deposition techniques. There are various method of thin film depositions as well as synthesis of material used by the researchers. Researchers are busy to find the different applications of the materials. With proper synthesis method and with proper doping of materials, different materials have the huge applications in sensing area. Most of the materials are used as a photo sensor, gas sensor, humidity sensor, chemical sensor, temperature sensor etc. [1] Thin films can be made by using, sterilized substrate, base material which is to be deposit, a source for the film material, needs to stick material with substrate and etching of film to attain the certain pattern of the film. Many oxides of materials found on earth are widely used in different sensing devices. TiO2, SnO2, ZnO, ZrO2, CeO2-ZrO2, Cr2O3, WO3, Al2O3, Y2O3 etc are the most important oxides used as sensors. [2-5] Out of all the oxides present on the earth, Titanium oxide is found to be widely used material and the study related to TiO2 is going on large scale by the researchers. Titanium dioxide (TiO2) has been an important material for decades, combining numerous attractive properties in terms of economy (low price, large availability) or ecology (non-toxic), as well as broad physical and chemical possibilities. It is found that, TiO2 is used as a photo sensor, humidity sensor, ethanol sensor, organic vapor sensor, environmental chemical species sensor, pH sensor etc. 2. APPLICATIONS OF TiO2 When pure polypyrrole (PPy) and TiO2 nanoparticles /polypyrrole (TiO2 NPs/PPy) form composite thin films on an alumina substrate, characterization shows that, it can be used as humidity sensor. [6] The sensor made of TiO2 NPs/PPy composite thin films, using the added amount of TiO2 NPs as 0.0012 g showed the highest sensitivity, smaller hysteresis and best linearity. Moreover, other sensing properties, such as effects of applied frequency, ambient temperature [7], response and recovery time and long- term stability were also investigated [8]. A new type of solar cell (called of the third generation) based on the use of a TiO2 layer sensitized with a dye (dye-sensitized solar cell [DSSC]). This cell differs