The key requirements to construct highly foldable solar cells, including structure design based on tuning the neutral axis plane, and adopting flexible alternatives including substrates, transparent electrodes and absorbers, are intensively discussed.
Key points for achieving highly foldable solar cells Compared to the normal bendable solar cells which can endure flexion with a smooth curve with radius of several millimeters, foldable solar cells can tolerate the crease at the edge with a curvature radius of sub-millimeter.
Several types of active materials, such as a-Si:H, CIGS, small organics, polymers, and perovskites, have broadly been investigated for flexible solar cell application. In the following sections, we will discuss the fundamentals of these materials and their strength, weaknesses, and future perspectives for flexible solar cells.
In general, if a photovoltaic material can be deposited onto a substrate at temperatures below 300 °C, the material can potentially be used in fabricating flexible solar cells. Several types of active materials, such as a-Si:H, CIGS, small organics, polymers, and perovskites, have broadly been investigated for flexible solar cell application.
When the solar modules subjected to folding, the Jsc started to decrease and gradually saturated at around 4 mA cm -2 after 10 cycles of folding/unfolding, while the Voc almost remained constant throughout 40 times folding/unfolding, as shown in Figure 3D. Foldable solar cells with crease in the predesigned place.
Schematic structure of solar cells comprising various functional materials: a flexible substrate, two electrodes, and an active layer. The direction of light entry to the active layer determines the optical requirement for the substrate and the electrodes. Fig. 3. Reported best efficiencies of solar cells made with various active materials.