Inkjet Printed Transparent Conductive Thin Films And Its Application Study In Quantum Dots Light-emitting Diodes

Oxide transparent conductive film is a semiconductor material with a wide band gap.It is widely used in thin film solar cell,electroluminescent diode,thin film transistor,touch screen and other devices because of its excellent photoelectric performance.Indium tin oxide（ITO）film has the best photoelectric performance and is the most widely used transparent conductive material.However,due to the decreasing raw material of ITO and its high production cost,transparent conductive films such as fluorine doped tin oxide（FTO）and aluminum doped zinc oxide（AZO）have emerged.This thesis attempts to use an ionic liquid assisted inkjet printed method to reduce the production cost of ITO film,at the same time try to prepare FTO film by ionic liquid assisted spinning coating.And ITO films prepared by inkjet printed are applied in quantum dots light-emitting diode.The main contents and results of this thesis are as follows:（1）ITO films are deposited by inkjet printed.ITO printed ink is prepared by dissolving indium hydroxide and tin chloride into ethanol with the assistance of acetic acid/tert-butylamine ionic liquid.Ionic liquid assisted ITO ink exhibits complete wetting behavior on the glass substrate with adjustable viscosity,which is especially suitable for the preparation of ITO film by inkjet printed.After reducing gas annealing at 500℃,ITO film with a sheet resistance of 99Ω/□,a resistivity of 2.28×10-3Ω·cm and a transmittance of 95.2%（400-1000nm）was obtained.The effects of annealing temperature on resistivity,mobility,carrier concentration,transmittance and optical band gap of inkjet printed ITO films were systematically investigated.Compared with commercial ITO films prepared by traditional vacuum deposition method,this printable ITO film has a higher material utilization rate.（2）FTO films are prepared by spin-coating method.The FTO solution is obtained by dissolving ammonium fluoride and tin chloride into ethanol with the help of butyric acid/butylamine ionic liquid.The prefabricated FTO film is prepared by spinning coating method.After vacuum annealing at 500℃,the FTO film with thickness of 800 nm,sheet resistance of 375Ω/□,resistivity of3.007×10-2Ω·cm and transmittance of 90.2%（400-100 nm）is obtained.The effects of annealing temperature on sheet resistance,resistivity,mobility,carrier concentration,transmittance and optical band gap of FTO films are systematically investigated.（3）ITO film prepared by inkjet printed is applied to quantum dots light-emitting diode（QLED）.In this thesis,it is applied to QLED with an inverted structure（ITO/Zn O/QDs/CBP/Mo O₃/Al）,and the maximum current efficiency and power efficiency are 10.96 cd/A and 3.75 lm/W,respectively.The results show that inkjet printed ITO films has high potential in QLED.