油墨粘度对卷对卷印刷有机光活性层的油墨转移速率和薄膜缺陷的影响机理

The influence mechanism of ink viscosity on ink transfer rates and film defects of the roll-to-roll printed organic photoactive layers

卷对卷(R2R)凹版印刷具有高的边缘分辨率、可图案化、高加工速度等优势,是制备大面积柔性有机太阳能电池(FOSCs)的一种可行技术.有机光活性层的薄膜质量是决定有机太阳能电池器件性能的关键.对于凹版印刷过程而言,墨水的转移是影响印刷薄膜厚度和质量的关键.本文深入研究了有机光活性层的墨水粘度对墨水转移率和薄膜缺陷的影响.我们开发了紫外可见光谱法,量化凹版印刷过程中墨水的转移率.通过对墨水的流变行为分析、流体动力学模拟和实验验证,深入研究了油墨粘度与油墨转移率、膜厚和膜均匀性之间的关系.结果表明,油墨粘度约为25 m Pa·s是R2R凹版印刷有机光活性层薄膜的适合粘度.通过对油墨配方的优化,我们制备了全R2R印刷FOSCs,其中1 cm^(2);电池的效率超过12%.

Roll-to-roll(R2R)gravure printing has significant potential for the mass production of large-area flexible organic solar cells(FOSCs)owing to its exceptional edge resolution,patternability,high speed,and high throughput.For gravure-printed FOSCs,device performance is critically dependent on the quality of the printed films.During the gravure printing process,printing transfer is a key step that impacts the film thickness and quality.This study delves deeply into the influence of ink viscosity on the ink transfer process,specifically focusing on the transfer rate and defects in printed films.In this work,we developed an ultravioletvisible(UV-Vis)spectroscopy method to quantify the ink transfer rate during printing.We conducted an in-depth investigation into the relationships among ink viscosity,transfer rate,film thickness,and film homogeneity through ink flow behavior analysis,computational fluid dynamic simulation,and experimental validation.The results demonstrate that the shear adhesion force and duration of contact between the ink and the gravure roll are crucial factors affecting the transfer rate.Furthermore,we identified an organic precursor ink with a viscosity of approximately 25 mPa·s as an optimized ink formulation for R2R gravure printing.With this optimized ink formulation,fully R2R-printed FOSCs with an area of 1 cm^(2)achieve a power conversion efficiency(PCE)exceeding 12%.