狭缝涂布大面积氧化锌薄膜的制备及其在柔性有机太阳能电池中的应用

Slot-die coated large-area ZnO films for flexible organic solar cells

发展有机太阳能电池的印刷法制备技术是实现有机光伏产业化的关键。在有机光伏器件中,氧化锌是常用的电子传输层材料。氧化锌纳米粒子在印刷过程中的自聚集,以及大面积薄膜干燥的不均匀,严重影响了大面积印刷有机光伏器件的性能。通过调控氧化锌墨水溶剂和引入墨水分散添加剂,获得一种适用于大面积涂布的氧化锌纳米墨水。其中复合溶剂的使用调控了氧化锌墨水的流变特性,进而改善了涂布薄膜中的边缘效应;而乙醇胺添加剂的引入解决了墨水在存放和印刷过程中的聚集问题。该墨水具有18个月以上保存稳定性,以及优异的狭缝涂布适印性。基于上述墨水,采用狭缝涂布方法制备获得的100×100 mm^(2)尺寸的大面积涂布薄膜具有优异的均匀性。将印刷的大面积氧化锌薄膜作为柔性有机太阳能电池的电子传输层,获得1 cm^(2)柔性有机太阳能电池的效率超过了14%,同时表现优异的重复性。

The preparation of large-area organic solar cells through coating or printing is the key to realizing the industrialization of organic photovoltaics.In the organic solar cells,ZnO is a commonly used material as an electron transporting layer.However,the self-aggregation of ZnO nanoparticles and the uneven drying of films during printing cause large numbers of defects and poor uniformity in large-area films,which seriously affects the performance of large-area printed organic photovoltaic devices.In this work,a ZnO nanoink suitable for large-area slotdie coating was developed by regulating solvent and introducing an ink dispersion stabilizer.The rheological properties of ZnO nanoink were regulated by using a mixed solvent,which solved the issue of edge effect in the coated film.The introduction of ethanolamine additives solves the problem of ink aggregation during storage and printing,allowing the ink to maintain long-term stability during 18 months of storage.With this nanoink,large-area films with a size of 100×100 mm^(2) were obtained by slot-die coating.Such a film shows excellent film uniformity.Using the printed large-area ZnO films as electron transporting layer,an efficiency of higher than 14%is obtained for 1 cm^(2) flexible organic solar cells.