Preparation Of Al-Doped ZnO(AZO) Particle-Free Ink And Properties Of AZO Film

In recent years,due to the development of electronic science and technology,electronic products have become popular,resulting in the increasement in market demand.As the key part of electronic devices,transparent conductive films have received a lot of attention,ITO films have been commercialized due to their good optical and electrical properties.However,the costs of ITO film are high due to the rare of indium and the complexity of the preparation process.Therefore,it is focus to research alternative transparent conductive films and combinie new fabrication techniques.ZnO is a wide band gap semiconductor with a direct band gap,and aluminum doped ZnO thin film received extensive attention not only their excellent optical and electrical properties,but also rich in source.There are many disadvantages of prepare oxide film by the conventional solution method,such as random orientation of crystal grains and untightness.Therefore,in order to improve the properties of film,the key point is to adjust the microstructure of the film by adjust the properties of the solution.Inkjet printing as an important implementation of printed electronics has effectively solved the above problems.Functional ink is the core of the technology.Compared to the particle ink,the particle-free ink has the advantages of good stability,simple synthesis steps,low sintering temperature,and difficulty in clogging the nozzle.Main research contents included:(1)In this paper,the particle free AZO ink consists of Zn precursors,Al precursors,complexing agent,solvent and additives was prepared by complexing metal ions with organic amines.Final formulation of particle-free AZO ink had stable performance and good ink-jet printing performance.The best formulation was:Zn(CH3COO)2·2H2O as Zn source,Al(NO3)3·9H2O as Al source,1,2-diaminopropane as complexing agent,ethanol as solvent,molar ratio of zinc-amine=1:4,ethyl cellulose(4 wt.%)as assitant.(2)The effects of the concentration of ink,Al doped amount and heat treatment process on the microstructure and photoelectric properties of the film were investigated.The film without Al doped,annealed at 500℃ in hydrogen atmosphere showed the stable resistivity of 56Ω·cm with ink concentration of 0.2 M.The film with 1.5 at%Al doped had the lowest resistivity of 0.03 Ω·cm and transmittance of 80%.Then,the resistivity of the film increased with the increasing on the Al doping amount.The resistivity of film with 2 at%Al doped and 3 at%were 2.34Ω·cm and 7.17 Ω·cm,respectively.(3)In combination with hydrothermal and inkjet printing technology,AZO was printed.as a seed layer on the treated flexible substrate and glass substrate to obtain AZO nanorod array film.When the concentration of the growth solution was 25 mM,a sheet morphology was obtained;The growth solution concentration was 40 mM,and the nanorods after hydrothermal reaction for 2 h were about 80 nm in diameter and 850 nm in length,with a thin film as the seed layer.