Acid Treated Carbon Nanotubes Raise Efficiency and Durability of Flexible Perovskite Solar Modules

Why It Matters

This breakthrough combines high efficiency with robust stability in a low‑cost, ITO‑free architecture, addressing two major barriers to commercializing flexible perovskite photovoltaics. It opens a pathway for large‑area, roll‑to‑roll production of lightweight solar modules for building‑integrated and portable power applications.

Key Takeaways

• Acid-treated SWCNT electrodes boost perovskite efficiency above 20%.
• Hydrophobic nanotube films block moisture, enhancing stability.
• Conductivity increase enables ITO-free cells reaching 24% efficiency.
• Modules retain >95% performance after one month harsh testing.
• Roll-to-roll SWCNT production supports large‑area flexible solar manufacturing.

Pulse Analysis

The race to commercialize perovskite photovoltaics has been driven by their record‑high power‑conversion efficiencies and low‑temperature processing, yet most demonstrations remain rigid and vulnerable to moisture. Flexible perovskite solar modules promise lightweight, bendable power sources for building‑integrated photovoltaics, wearables, and remote sensors, but achieving both high efficiency and long‑term durability has proved elusive. Conventional transparent conductors such as indium‑tin‑oxide (ITO) add brittleness and cost, prompting researchers to explore alternative electrodes that can sustain repeated bending while protecting the perovskite layer from environmental degradation.

The new study leverages sulfuric‑acid‑treated single‑walled carbon nanotube (SWCNT) films as a hydrophobic, highly conductive window electrode. Acid treatment removes residual surfactants, increases carrier density, and promotes the formation of a compact NiSO₄–NiOₓ interfacial layer that bridges the perovskite absorber and the hole‑transport material. This architecture eliminates the need for ITO, delivering laboratory‑scale cell efficiencies above 24% and flexible module efficiencies exceeding 20%. Crucially, the moisture‑repellent nanotube network enables the devices to retain over 95% of their initial output after a month of high‑temperature, high‑humidity, continuous illumination testing.

Beyond performance, the researchers demonstrated a roll‑to‑roll chemical vapor deposition process capable of depositing SWCNT films on meter‑scale substrates, a key step toward mass production. The low material cost and compatibility with existing roll‑to‑roll lines could dramatically reduce the capital expense of flexible perovskite solar factories. As the industry seeks carbon‑neutral energy solutions, these durable, ITO‑free modules are well‑suited for integration into façades, rooftops, and portable power systems, potentially accelerating the adoption of lightweight solar technology and lowering overall greenhouse‑gas emissions.