Acid treated carbon nanotubes raise efficiency and durability of flexible perovskite solar modules

by Riko Seibo

Tokyo, Japan (SPX) Dec 16, 2025

Flexible perovskite solar modules are emerging as a candidate for lightweight, bendable photovoltaics, but maintaining high efficiency while preserving long term stability and low cost remains difficult. A research team from the Institute of Metal Research of the Chinese Academy of Sciences and Zhengzhou University reports flexible perovskite solar modules with power conversion efficiency exceeding 20 percent that tolerate mechanical and environmental stresses. The work focuses on single walled carbon nanotube films used as window electrodes in scalable flexible perovskite solar modules.

The team shows that single walled carbon nanotube films are hydrophobic, which helps block moisture and slows degradation of the perovskite layer, improving device stability. Their mechanical flexibility and relatively low material cost make these carbon nanotube electrodes suitable for application in distributed power generation integrated into buildings and infrastructure that support reduced carbon emissions.

A central step in the study is treatment of the carbon nanotube network with sulfuric acid. The acid treatment increases the electrical conductivity of the nanotube films and promotes interaction with nickel oxide to form a compact NiSO4 – NiOx layer at the interface.

This interfacial layer improves charge transfer between the perovskite absorber and the hole transport material, enabling indium tin oxide free perovskite solar cells to reach more than 24 percent power conversion efficiency, with flexible devices maintaining roughly 23 percent. Under high temperature, high humidity, and continuous solar illumination for one month, these devices retained more than 95 percent of their initial efficiency.

The researchers also fabricated flexible, module scale, indium tin oxide free devices using a straightforward and scalable process, achieving more than 20 percent efficiency with improved stability and bending performance. The work further demonstrates that single walled carbon nanotube films can be produced on meter scale substrates through a chemical vapor deposition based roll to roll process, which supports larger area manufacturing of carbon nanotube based perovskite modules.

Together, the findings indicate that sulfuric acid treated carbon nanotube electrodes prepared by established acidic processing routes can raise both performance and durability in flexible perovskite solar technologies.

Research Report:Integrating SWCNT to Bridge the Stability Divide in Scalable and Manufacturable Flexible Perovskite Solar Modules