Lightweight and ultra-flexible perovskite solar cells with a “sandwich” perovskite layer based on graphene–carbon nanotube electrodes

Abstract

Flexible perovskite solar cells (FPSCs) have sparked widespread research enthusiasm due to their great potential in the booming fields of flexible electronics and portable devices. A lot of research has been conducted on the performance, flexibility, and stability of FPSCs, but the synergistic improvement of all three is still extremely difficult. In this work, we have achieved a lightweight and ultra-flexible perovskite solar cell (LWUF PSC) with high performance and remarkable stability. Specifically, in addition to using a 1.5 μm-thick polyetherimide film as a flexible substrate, the improved scheme mainly includes designing a “sandwich” architecture with multifunctionality to take advantage of perovskite quantum dots and polycrystalline perovskite, employing a flexible graphene–carbon nanotube film electrode, and a CuCrO₂ nanoparticle-based hole transport layer containing nickel to facilitate the transfer of photogenerated charge carriers. The resultant device demonstrates a stable power conversion efficiency (PCE) of 17.4% and a power-per-weight of 31.1 W g⁻¹. In particular, after 10 000 bending cycles with a curvature radius of 1 mm, the PCE of the LWUF PSC has sustained at 92.8% of its initial level, and after 32 days in an atmosphere with a relative humidity of 35%, it has remained at 93.0% of its initial level. The unique structural design of the device gives the LWUF PSC high PCE, significant power-per-weight, excellent mechanical flexibility and outstanding environmental stability, representing one of the best-performing LWUF PSCs to date without indium tin oxide electrodes.