Nanomaterials in 2-dimensions for flexible solar cell applications - a review

This review presents the progress, challenges and prospects of ultrathin flexible photovoltaic devices based on 2-dimensional (2D) nanomaterials. These devices have shown very high performance in bending stabilities for up to -90% of their power conversion efficiencies (PCEs) after multiple bending deformations. They are thin film PVs with lightweight and mechanically robust structures that allow use in the continual advancing solar cell applications. In this paper, comprehensive assessments of 2D nanomaterials, their syntheses methods, performance, degradation, mechanical and opto-electronic characterization in flexible photovoltaic (PV) cells are highlighted. Semi-conductor materials such as conjugated donor and acceptor polymers, small donor/acceptor molecules and organometal halide perovskites for use as active layers in such flexible solar cell structures are reviewed. The challenges and prospects associated with the adoption of 2D nanomaterials in flexible solar cells are presented. The review highlights the need to transition laboratory results on 2D nanomaterials based flexible solar cells into scale up and commercialized products despite the existing and also opens research areas for researchers to explore and achieve robust and high-efficient solar devices.