Eco-friendly method enhances perovskite solar cell quality using camphor-based additive

A recent study demonstrates how a substance derived from camphor, a natural extract from the camphor tree, can significantly improve the quality of perovskite thin films used in solar cells. This material’s sublimation property—its ability to transition directly from solid to gas without leaving residues—has been harnessed to enhance device performance and manufacturing efficiency.

The research team led by Professor Changduk Yang at the School of Energy and Chemical Engineering at UNIST successfully synthesized high-quality perovskite films by incorporating camphor derivatives. The absence of residual substances is expected to extend the lifespan and efficiency of solar cells while simplifying fabrication processes and reducing production costs. The findings are published in the journal Energy & Environmental Science.

Perovskite thin films in solar cells are composed of numerous crystal grains. Larger, well-ordered crystal grains facilitate smoother electron flow and strengthen structural integrity, leading to improved efficiency and durability. To achieve such high-quality structures, additives are often employed during fabrication; however, residual additives can sometimes hinder device performance.

To address this issue, the researchers utilized camphorquinone (CQ) as an additive. CQ is a derivative of camphor, which is extracted from the camphor tree, modified with an oxidation group. Unlike camphor, which sublimates directly from solid to gas, CQ undergoes stepwise sublimation—initially assisting in uniform seed crystal formation during the first thermal treatment, then gradually sublimating completely during the second heating process. This controlled sublimation allows the perovskite film to grow optimally without residual contaminants.

Researcher Jeewon Park, the first author of the study, explained, “CQ can be precisely timed to influence the crystal growth phase and leaves no residual material in the film. This unique property enabled us to produce high-quality perovskite films.”

Solar cells fabricated with these CQ-enhanced films demonstrated a power conversion efficiency (PCE) of 25.2%, surpassing the 23.0% efficiency of control devices without additives—an improvement of approximately 9.6%.

Under maximum power point tracking (MPPT) testing, which simulates real-world operating conditions, these devices retained more than 90% of their initial efficiency after 1,000 hours, more than doubling the operational lifespan of comparable control devices. MPPT is a rigorous standard that evaluates the stability of solar cells under simulated sunlight.

Professor Yang said, “Solving stability issues in perovskite solar cells using eco-friendly, naturally derived materials not only advances sustainable energy technology but also paves the way for more durable, cost-effective solar solutions.”