Synthesis and characterisation of B-TiO2 thin films by atmospheric pressure chemical vapour deposition and plasma enhanced chemical vapour deposition : functional films for different substrates

Anatase, a form of titanium dioxide (TiO2), is arguably the most studied wide band gap semiconducting photocatalyst. TiO2 has many other applications, including water and air purification, self-cleaning surfaces and photovoltaic. However, for many applications, as well as for safety concerns related...

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Bibliographic Details
Main Author: Quesada-Gonzalez, Miguel
Published: University College London (University of London) 2018
Subjects:
540
Online Access:https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.756289
Description
Summary:Anatase, a form of titanium dioxide (TiO2), is arguably the most studied wide band gap semiconducting photocatalyst. TiO2 has many other applications, including water and air purification, self-cleaning surfaces and photovoltaic. However, for many applications, as well as for safety concerns related to the handling of nanoparticles, the simultaneous synthesis and deposition of photocatalytic TiO2 thin films is highly desirable. Numerous routes towards the simultaneous synthesis and deposition of anatase TiO2 thin films have already been reported. Chemical vapour deposition (CVD) methods have successfully been implemented for the industrial production of photocatalytic TiO2 thin films. Nevertheless, the rather high temperature required in CVD does not allow the coating of heat sensitive substrates. Similarly, other photocatalytic TiO2 deposition processes all possess significant drawbacks, such as the lowpressure environment required by physical vapour deposition (PVD) and the post-heating treatment or the large number of steps required by sol-gel approaches. In addition, most of the methods remain difficult to implement on complex shape substrates and/or non-conformal. The following research thesis reports on new functional coatings, based on boron-doped TiO2, which were deposited by APCVD and AP-PECVD on different matrices and substrates. Boron, as a dopant for TiO2 systems, has been used and reported to enhanced TiO2 photocatalytic performance under UV light, as well as numerous scientific papers reported on the visible light response of borondoped TiO2. However, in most of the cases the successful B-TiO2 was synthesised in the form of powders, not thin films. Also, when B-TiO2 thin films were synthesised, only substitutional boron-doped TiO2 was previously reported, whereas, the higher stability and long-term life of interstitial boron vs substitutional has been proven and reported theoretically and experimentally.