Integrating Perovskite Solar Cells into a Flexible Fiber

TLDR: Perovskite solar cells with a flexible fiber structure were prepared for the first time by continuously winding an aligned multiwalled carbon nanotube sheet electrode onto a fiber electrode; photoactive perovskites materials were incorporated in between them through a solution process.

Abstract: Perovskite solar cells have triggered a rapid devel- opment of new photovoltaic devices because of high energy conversion efficiencies and their all-solid-state structures. To this end, they are particularly useful for various wearable and portable electronic devices. Perovskite solar cells with a flexible fiber structure were now prepared for the first time by continuously winding an aligned multiwalled carbon nanotube sheet electrode onto a fiber electrode; photoactive perovskite materials were incorporated in between them through a solu- tion process. The fiber-shaped perovskite solar cell exhibits an energy conversion efficiency of 3.3 %, which remained stable on bending. The perovskite solar cell fibers may be woven into electronic textiles for large-scale application by well-developed textile technologies. Perovskite materials with the formula CH3NH3PbX3 (X = Cl, Br, I) have been known for several decades and have recently attracted increasing attention because of their promising applicability in photovoltaics. (1-3) A typical perov- skite solar cell is composed of an n-type compact layer that blocks short circuits, a mesoporous TiO2 nanocrystal layer, a light-harvesting perovskite layer, a hole-transport layer, and two electrodes. The perovskite layer absorbs light to generate charges that are driven to be separated and transported by the built-in electric field between the two electrodes; this is followed by injection of the electrons into the conduction band of the TiO2 layer and of the holes into the hole-transport layer; they are then collected by the electrodes. (4, 5) Perovskite solar cells exhibit high energy conversion efficiencies of up to 16 %, which are much higher than those of polymer solar cells. (6-8) Furthermore, an all-solid-state structure is produced with high environmental stability, which is particularly important for high-performance flexible devices. (9, 10) Indeed, flexible perovskite solar cells with high energy conversion efficiencies, for example, 10.2 %, have recently been reported. (11, 12)