The Optimization Of Photoelectric Performance Of AZO Thin Film And Mechanical Behavior On Flexible Substrates

The AZO(ZnO:Al)thin film produced by low-cost roll-to-roll(R2R)method own a character of light quality,flexible and cheap,which lead it to widely used in the area of solar cells,flexible electronic displays,flexible piezoelectric micro-generators and flexible sensors and so on.However,flexible substrate,mainly organic polymer,cannot work in a hightemperature circumstance,which effect the prepared of high quantity AZO film.In addition,the flexible film usually lose efficacy caused by stretch,bending and so on.It prevent the widely used with low cost.Therefore,it has been a popular trend to figures out the problem to prepare AZO film with good photoelectricity and stability of bending.In this paper,the performance of AZO film is studied on the both side of improving photoelectric property and mechanical tolerance.Firstly,the experiment method of orthogonal L9(34)was took advantaged to investigate the effect of muti-factor and muti-level deposit manufacturing to the properties of film.Studies have shown that sputtering time has a significant impact on sheet resistance(58.3%contribution)and optical transmittance(49.1%contribution).The gray correlation analysis method was used for multi-objective optimization,and the influence of the significant factor of sputtering time was considered to obtain the optimal process parameters(sputtering power 100 W,sputtering pressure 1.0 Pa,sputtering time 20 min,substrate temperature).In order to reduce film defects caused by low lattice fit between the film and the flexible substrate,an aluminum-containing buffer layer is introduced between the flexible substrate and the AZO film to improve.the performance of the AZO film.The results show that the introduction of the Al buffer layer significantly reduces the square resistance of the AZO film,but the thickness of the Al buffer layer is sensitive to the optical transmittance of the AZO film.The Al2O3 buffer layer can ionize part of Al3+ instead of Zn2+,refine the grain of AZO film and optimize the performance of AZO film.In addition,this paper explores the effect of hydrogen doping on the properties of AZO films under different H2/Ar ratio conditions.Studies have shown that an appropriate amount of hydrogen can etch weak bonds in the film to improve film defects,and further optimize the photoelectric properties of AZO films.At the same time,in view of the fact that the flexible AZO transparent conductive film is often subjected to deformation such as stretching and repeated bending during production and use to improve the reliability of the AZO film.Buffer layer is explored under the optimized sputtering process conditions.The effect on the yield strength and tensile strength of the film.Studies have shown that with buffer layer,tensile strength and yield strength of AZO film are significantly increased,but the ultimate strain of the film is gradually reduced.In addition,this paper uses a general full factor test design to systematically study the effect of mechanical bending strain on film properties.Studies have shown that the bending radius and the bending direction have a significant influence on the electrical properties of the AZO film,and there is also a certain interaction between the buffer layer and bending direction to affect the film properties.For reverse bending,the buffer layer improves the resistance to reverse bending of the film over a range of bending strains.For the positive bending,the buffer layer may preferentially generate microcracks in the AZO film,accelerate the expansion of the film bending crack,which increase the film square resistance.In addition,when the flexible AZO film is bent in multiple cycles,the change of the film square resistance is more sensitive to the bending strain,and under the same bending condition,the positive bending has better reliability than the reverse bending.For the reverse bending,the introduction of the Al2O3 buffer layer is to reduce the percentage change rate of the film sheet resistance within a certain strain range,and buffer layer contribute to limiting the microcrack develops into the main crack.In summary,this paper studied the deposition process with multi-factor and multi-level deposition,buffer layer,conducts hydrogen doping and so on.Depositing AZO film with good photoelectric performance and uniformity on flexible PET substrate.When the photoelectric performance of the flexible AZO film has reached the industrial application standard,the failure behavior of the flexible AZO film under mechanical strain is studied to improve the mechanical reliability of the high quality AZO film,and provide a large-area application for the AZO film on the flexible substrate surface.