Boosting the Mechanical Stability and Power Output of Intrinsically Stretchable Organic Photovoltaics with Stretchable Electron Transporting Layer

The stretchability of electron transport layer (ETL) has the operational effects on intrinsically stretchable organic photovoltaics (IS-OPVs). The highly stretchable ETL reinforces the stability of IS-OPVs under strain. Consequently, the device performances are maintained, and the power output is significantly increased at 20% strain.

Abstract

Intrinsically stretchable organic photovoltaics (IS-OPVs) are emerging as power sources for wearable technologies, enabling seamless integration into flexible and stretchable systems. A key feature of IS-OPVs is the potential for increased power output as the photoactive area expands during stretching. However, current mechanical performance and stability still fall short of meeting the demands for practical applications. To overcome this limitation, the study introduces, for the first time, a polymer:gel blend system as a highly stretchable electron transporting layer (ETL), which significantly enhances both the power output and mechanical stability of IS-OPVs. This novel ETL plays a pivotal role in dissipating mechanical stress and protecting the brittle underlying layers. By incorporating this stretchable ETL, the device stretchability is reinforced by introducing the stretchable ETL, thereby maintaining the initial power conversion efficiency under 20% strain. As a result, the maximum power output substantially increases by 23%, from 0.28 to 0.35 mW, under large strain, while devices with conventionally brittle ETLs caused a 33% reduction in power output. This study thus offers a pathway toward durable and efficient stretchable photovoltaics.