This PhD thesis investigates doped titanium dioxide (TiO2) thin films for sensor applications. TiO2 was doped with 5% aluminum (Al) and copper (Cu) using sol-gel techniques. The structures, surface morphologies, optical properties, and sensing performance of pure, Cu-doped, and Al-doped TiO2 films were characterized. The materials were tested for gas and humidity sensing, finding that frequency shifts in a quartz crystal microbalance sensor coated with the thin films could indicate the type and amount of gas or humidity present. The doped TiO2 films also showed potential for photocatalytic degradation of contaminated water. The thesis provided new information on the properties of pure and doped TiO

1. DOPED TiO2 THIN FILMS:
PRODUCING, CHARACTERISATION AND INVESTIGATION OF APPLICATIONS
AS A SENSOR
(Ph.D. THESIS)
ALİRIZA SAYIN
ABSTRACT
TiO2 is a popular material in many areas for search or applications. Its versatility is the main
reason for popularity. In this thesis, TiO2 doped in the rate of %5 with Aluminum (Al) and Copper (Cu).
Three types of TiO2 (pure, Cu and Al doped) materials are analyzed in various aspects. Allmaterials are
produced by using sol-gel techniques on the glass bases. Analyses focused on structural, surface
morphology, optical. Three types of material examined for their gas and humidity sensing and
photocatalytic features. Structuralanalysis brings out the characteristic properties; electron microscopy
images ensuredsurface morphology information. Pure,Cu and Al doped TiO2 materials are investigated
to observe whether they can be used as gas and/or humidity sensor or not. Photocatalytic and optic
features are examined; their optical refractances and transmittance measurements are measured. The
materials are used as photocatalytic degrader in specifically contaminated water.
Computer controlled gas flow system is used for gas and humidity sensing. The materials are
covered as a thin film on the Quartz Crystal Microbalance (QCM) sensor and they are used in the gas
flow system to find out how the reference frequency shifted by the humidity and various gases. The
frequency shifts are measured and commented about the selectivity, sensitivity and stability of the
materials.
The work produced important information of pure, Cu and Al doped TiO2 thin films on the
structural, optical morphological aspects. The other information that has been released from the work is
how the materials can be used as gas and humidity sensor and photocatalytic degradation.
Key Words: TiO2, Cu doped TiO2, Al doped TiO2, sol-gel, photocatalytic, optic, gas sensor, humidity
sensor