Fabrication And Study Of Non-fullerene Organic Solar Cells Based On Low Temperature Zinc Oxide Aqueous Solution

Due to the low cost,simple preparation process and flexibility of organic solar cells,it has attracted a lot of attention in recent years,but its low efficiency and poor stability have hindered its large-scale commercial development.At present,inverted-structured organic solar cells have been proven to effectively improve device reliability,and organic solar cells with polymers and non-fullerene receptor systems have made new breakthroughs in efficiency.The topic of this thesis comes from the National Natural Science Foundation of the experimental group.The main research content is based on low temperature zinc oxide aqueous solution and PBDB-T:IT-M organic layer as light absorption layer to prepare high performance organic solar cells.Non-fullerene organic solar cells were prepared on flexible substrates.The research results are as follows:In the first part,the choice of the material of the cathode buffer layer plays an important role in the performance of the device of the inverted structure.The common cathode buffer layer materials are Ti O2,Zn O and so on.Due to the excellent material properties of zinc oxide materials,it is particularly widely used in inverted-structured organic solar cells.In the preparation of zinc oxide thin films,the preparation of the cathode buffer layer by the solgel method requires high-temperature(200 ° C-400 ° C)annealing to obtain a film with good performance,and is not suitable for preparing flexible electronic devices,and the lowtemperature zinc oxide.aqueous solution can overcome the above disadvantages.Therefore,I based on the laboratory’s research of low-temperature zinc oxide aqueous solution,and the structure of Glass/ITO/Zn O/PBDB-T:IT-M /Mo O3/Ag,by optimizing the process conditions of PBDB-T:IT-M organic layer,the high performance organic solar cell is prepared under low temperature process,the conclusion is as follows: When the annealing temperature of PBDB-T:IT-M organic layer is 160 °C,the device with better performance can be obtained;When the speed of the spin-on PBDB-T:IT-M organic layer is 3000 r/min,the thickness of the organic layer is close to 100 nm,and a device with better performance can be obtained.Subsequently,an organic solar cell with a structure of Glass/ITO/Zn O/PBDB-T:ITM/Mo O3/Ag was prepared by using a low-temperature zinc oxide aqueous solution and a sol-gel zinc oxide solution in the experiment,and the comparison was based on different methods.The difference in performance of the device for preparing the zinc oxide layer,wherein the organic solar cell device prepared by the low-temperature zinc oxide aqueous solution method achieves an efficiency of 9.3%,and the organic solar cell device prepared by the sol-gel method achieves an efficiency of 8.6%.The experimental results show that there is not much difference in the performance of the organic solar cells prepared by the low temperature zinc oxide aqueous solution method and the sol-gel zinc oxide layer.In addition,in order to study the reliability of the device prepared in the experiment,we exposed the unpackaged device in the air for 240 hours,and found that the performance was still maintained at 82%,which proves that the device has good reliability.In the second part,in order to study the feasibility of preparing low-temperature zinc oxide aqueous solution on a flexible substrate for high performance non-fullerene organic solar cells,the flexible device of structure PET/ITO/Zn O/PBDB-T:IT-M /Mo O3/Ag was prepared.It was found through performance testing that the performance of the flexible device was not very satisfactory compared to the device fabricated on the glass substrate.The efficiency of the device was less than 7%,which may be related to the experimental Annealing of the PBDB-T:IT-M organic layer destroys the contact between the interface layers.Moreover,in order to study the bending resistance of flexible devices,we performed bending operations with different radius of curvature and found that when the radius of curvature is not less than 0.8 cm,it can continue to work normally after 1000 folds,When the radius is not more than 0.5cm,the device will cause its performance to drop rapidly and close to failure after being folded many times.After that,the reason for the performance degradation of the device is briefly studied.Finally,the reliability of the flexible device was studied.The unpackaged flexible device was placed in the air for 240 hours,and the performance was still maintained at 83% of the initial value,which proves that the flexible device has good reliability.