In-situ morphology control for high-efficient organic photovoltaics

Ma Wei

Organic photovoltaics have significant industrial prospects in building integrated photovoltaics and flexible electronics, reducing the costs of device fabrication is an important way to promote its industrial production. At present, the processing of photoactive layers in organic photovoltaics can be mainly classified into three categories, namely spin coating, blade coating and slot-die coating. Among them, blade coating and slot-die coating are two typical meniscus-guided coating (MGC) techniques, which can form a meniscus under the action of viscous force and coat under unidirectional shear force to form an active layer with controllable thickness. These characteristics enable MGC to achieve high-throughput printing and high utilization of materials, and hold outstanding promise for decreasing the cost of device fabrication. However, compared with the commonly used spin coating, the mechanism of the MGC on the morphology of the active layer is not yet clear, and there is a lack of guidance for the optimization of morphology based on the characteristics of MGC technology, This has become a key issue restricting high-throughput and low-cost printing of active layers. In response to the above problems, this report will start from the film-forming process of MGC, analyze the mechanism of MGC on the morphology of active layer, propose a morphology control strategy suitable for MGC, and establish the whole-chain relationship between the solution state - kinetic process - morphology of the active layer. We expect this report to offer a reference for high-throughput and low-cost printing of efficient organic photovoltaics.