How to maintain stable long-term performance of perovskite solar cells？

In recent years, perovskite materials are rapidly becoming a popular candidate for solar energy. However, one of its main drawbacks is that it is easily decomposed in direct sunlight. The good news is that a team of researchers at the University of California, Los Angeles (UCLA) has just introduced a new coating for perovskite photovoltaic panels featuring improved stability in sunlight.

According to an article recently published in the journal Nature, UCLA researchers have found the root cause of the problem and proposed a simple application solution that can be implemented in the manufacturing process.

For a long time, silicon-based materials have occupied a considerable position in the field of solar cells, and few materials can match them in terms of efficiency, durability, cost and so on.

However, in recent years, with the rise of metal halide research, perovskites are rapidly growing into a serious competitor - in addition to being close to the efficiency of silicon-based materials, it is also lighter, more flexible, and less expensive.

One problem with perovskite materials, however, is that they are easily decomposed in direct sunlight, so their efficiency decreases over time.

Previous attempts by researchers to add macromolecules, old pigments, carbon nanodots made from hair, two-dimensional additives, pepper compounds, and even quantum dot technology have tried to salvage the durability issues of perovskite solar cells.

Fortunately, the UCLA team has found the mechanism behind the decomposition of perovskite materials. Ironically, the phenomenon turns out to be the result of surface treatment processes designed to repair defects and increase their efficiency.

It is reported that the process involves coating the surface with a layer of organic ions, but the research team found the disadvantage of doing so - energy-carrying electrons will accumulate on the surface of the perovskite photovoltaic panel.

To make matters worse, this condition in turn disrupts the arrangement of the perovskite atoms, eventually causing them to break down over time.

In view of this, the UCLA team thought of adding positive and negative ion pairs in the surface treatment process to solve this problem.

Not only does this help keep the surface neutral and stable, it doesn't interfere with the original defect prevention process.

To test the effect of the new coating process, the researchers conducted a simulated accelerated aging test of the improved perovskite solar panel in an all-weather bright light environment.

It was found that the new technology allowed the perovskite photovoltaic panel to maintain a conversion efficiency of up to 87% after 2,000 hours. In the untreated control group, it dropped to 65%.

In the end, study co-author Shaun Tan said: "Our perovskite solar cells achieve the most stable high efficiency known to date."

At the same time, the UCLA team has also laid a new foundational knowledge upon which the community can further develop and improve this multi-plane technology to advance the design of more stable perovskite solar cells.