Vladimir Kondratiev will defend his doctoral theses titeled "Processing and characterization of transparent electrode materials" on 24. August 2017 at 10.15 at W. Ostwaldi 1, room B103.
dr Alexey E. Romanov ITMO University, St. Petersburg, Russian Federation
dr Leonid Dolgov Institute of Physics, University of Tartu
dr Alexey V. Nashchekin (Ioffe Physical Technical Institute of RAS, St.-Petersburg)
dr Tatjana Dedova (Tallinn University of Technology).
Transparent conductive films are important components of modern optoelectronic devices such as solar cells, light-emitting diodes, and flat panel displays. These films have to be good electrical conductors while at the same time retaining transparency in a desirable optical range. There are many materials that possess separately a good conductivity or a good optical transparency, but only a few materials can combine all these properties at once. Currently the industry standard material is indium tin oxide (ITO). However, ITO is based on indium, which is an expensive element. To decrease the cost of transparent conductive films, alternative materials have to be developed. Additionally they have to be prepared by cheaper methods that are suitable for mass production. Since some prospects are connected with aluminium-doped zinc oxide (AZO) as such alternative material, this research focused on elaboration of relatively inexpensive sol-gel based methods of AZO films preparation and investigation of electrical and optical properties. In spite of certain amount of publications related to the AZO, there is no systematic data about preparation conditions by sol-gel method and resulting film properties. Partly it is caused by the fact that different authors controlled different preparation parameters in different ranges and some important experimental conditions are not fully described. This makes their result hard to reproduce. So in this work existing sol-gel approaches of preparation of AZO films were critically reconsidered and own recipes were elaborated in details whereas a good reproducibility of the method was achieved. We carried out a deep investigation of all the steps of the sol-gel procedure, practical preparation and thermal treatment of samples in different atmospheres, and analysis of their physicochemical properties. The resultant films were deposited by spin-coating and electrospinning methods from sol-gel solution with a goal to obtain films which are more suitable for electro-optical applications. Such specific optical properties as fluorescence and reflectivity of the AZO films were investigated also. Finally, to demonstrate possible application and real performance of the obtained AZO films as transparent conductive coatings, they were tested in the liquid crystal indicators, which are part of liquid crystal displays.