Manipulating the Macroscopic and Microscopic Morphology of Large-Area Gravure-Printed ZnO Films for High-Performance Flexible Organic Solar Cells

Gravure printing is a promising large-scale fabrication method for flexible organic solar cells(FOSCs)because it is compatible with two-dimension patternable roll-to-roll fabrication.However,the unsuitable rheological property of ZnO nanoinks resulted in unevenness and looseness of the gravure-printed ZnO interfacial layer.Here we propose a strategy to manipulate the macroscopic and microscopic of the gravure-printed ZnO films through using mixed solvent and poly(vinylpyrrolidone)(PVP)additive.The regulation of drying speed effectively manipulates the droplets fusion and leveling process and eliminates the printing ribbing structure in the macroscopic morphology.The additive of PVP effectively regulates the rheological property and improves the microscopic compactness of the films.Following this method,large-area ZnO∶PVP films(28×9 cm^(2))with excellent uniformity,compactness,conductivity,and bending durability were fabricated.The power conversion efficiencies of FOSCs with gravure-printed AgNWs and ZnO∶PVP films reached 14.34%and 17.07%for the 1 cm^(2)PM6:Y6 and PM6∶L8-BO flexible devices.The efficiency of 17.07%is the highest value to date for the 1 cm^(2)FOSCs.The use of mixed solvent and PVP addition also significantly enlarged the printing window of ZnO ink,ensuring high-quality printed thin films with thicknesses varying from 30 to 100 nm.

Additive Fine-Line Circuit Process through Catalyst Induced Copper Electroless Plating

To response the demand for fine line in electronic products,additive manufacturing process integrated printing techniques and deposited methods to reach fine line circuit,with the merits of reduced material wastage,low fabrication costs,and mass production advantage capability.Recently,we have developed additive process in fabricating circuit on flexible substrate through catalyst induced copper electroless deposition(ELD)method.The additive processes that integrated printing,activation,and metallization were applied to produce fine-line circuit with 5μm line width.The sample with ultraviolet(UV)activation shows better conductive property in comparison with the sample without activation after electroless deposited process.Accordingly,the results indicated that the reaction of catalyst induced electroless copper plating strongly depends on UV activation.The fine-line circuit exhibits a narrow line width circuit(around 5μm),lower resistance(6.2μΩ·cm),and mass production with low pollution in comparison with lithographic processes(with photoresist and acid pollution)with a high throughput system(R2R system)for the applications of double side flexible printed circuit board(FPCB).