Aggregation effects in ink solutions for organic photovoltaic devices

In organic solar cells the efficiency can be increased by using an additive. However in organic photovoltaics what the use of additives does to the underlying structure is not well understood. The additive 1,8-diodooctane (DIO) is highly used in organic photovoltaics. One major requirement for an additive to be a good additive is having preferential solubility to one of the components (typically the fullerene). However, very little information still exists in the literature on the solubility of conjugated polymers in pure additives such as DIO. In this proposal we aim to study the solubility and aggregation behaviour of these conjugated polymers in DIO and in DIO:CB-d5 solutions using SANS. This knowledge will be crucial for the comprehension of the effect of additives in organic photovoltaics and can be leveraged to the development of more efficient OPV devices.

在有机太阳能电池（organic solar cells）中，通过添加助剂可提升器件效率。然而在有机光伏（organic photovoltaics, OPV）领域，助剂使用对活性层微观结构的影响机制尚未得到充分阐明。助剂1,8-二碘辛烷（1,8-diiodooctane, DIO）是有机光伏领域应用极为广泛的添加剂。优质助剂的核心要求之一，是对活性层组分中的某一类（通常为富勒烯类材料）具有优先溶解性。但目前文献中关于共轭聚合物在纯助剂（如DIO）中的溶解性能的相关研究仍十分匮乏。本研究拟采用小角中子散射（Small Angle Neutron Scattering, SANS）技术，探究共轭聚合物在纯DIO以及DIO与CB-d5混合溶剂中的溶解与聚集行为。该研究成果将有助于阐明助剂在有机光伏体系中的作用机制，进而为开发更高效率的有机光伏（OPV）器件提供关键理论支撑。