• Sutherland, Luke
• Simon, George

Abstract

Organic Photovoltaics (OPV) and Perovskite Solar Cells (PSC) have undergone rapid development within the last decade, exhibiting exciting properties such as high efficiency, flexibility and the potential for large-scale fabrication through Roll-to-Roll (R2R) processing. Whilst several performance aspects of these devices have shown outstanding improvements over this time i.e. the Power Conversion Efficiency (PCE), operational stability is recognised to be an ongoing challenge as prolonged device lifetimes are scarcely observed. This instability can be narrowed down to both ‘intrinsic degradation’ such as ion migration in the presence of defects and ‘extrinsic degradation’, with exposure to moisture and oxygen proving to have detrimental effects on device performance. A means of delaying the degradation of flexible OPV and PSC devices to achieve the required operational lifetimes for commercial applications is via barrier encapsulation. Whilst glass encapsulation has shown to exhibit ideal barrier properties, the potential for flexible devices and high-throughput R2R mass-fabrication requires the development of flexible barrier materials and encapsulation methodologies. These barriers must demonstrate outstanding moisture permeation resistance, whilst also being transparent, chemically, and thermally stable, and able to withstand repeated mechanical deformation. Herein, the fundamental principles of OPV and PSC devices will be initially discussed, highlighting the degradation mechanisms and current stability obstacles. A review of the latest flexible barrier materials and encapsulation strategies will follow, focussing on stability studies that have been undertaken on flexible PSCs and OPVs, along with some suggestions as to the direction such research may take.

Topics

• perovskite
• impedance spectroscopy
• Oxygen
• glass
• glass
• defect
• power conversion efficiency