Engineers eliminate surface concavities to produce more efficient and stable perovskite solar cells

A analysis group from the Faculty of Engineering of the Hong Kong College of Science and Expertise (HKUST) has proven the existence of floor concavities on particular person crystal grains, that are the basic constructing blocks of perovskite skinny movies, whereas revealing their vital results on movie properties and reliability.

Primarily based on this elementary scientific discovery, the group has pioneered a brand new manner of creating perovskite solar cells extra environment friendly and secure through a chemo-elimination of those grain floor concavities.

Perovskite photo voltaic cells are a stellar solar-cell expertise that has demonstrated potential to exchange current silicon photo voltaic cells in a variety of software eventualities, corresponding to grid electrical energy, moveable energy, and house photovoltaics.

They not solely attain greater energy conversion efficiencies (PCEs) than industrial silicon cells, but additionally supply benefits when it comes to low materials prices, sustainable manufacturing, and excessive versatility in transparency and colours.

Nonetheless, the long-term stability of perovskite units beneath mild, humidity, and thermomechanical circumstances stays a hurdle within the commercialization of this promising photo voltaic expertise.

To deal with this challenge, Prof. Zhou Yuanyuan, Affiliate Professor of the Division of Chemical and Organic Engineering at HKUST, and his analysis group have performed analysis from the distinctive perspective of the supplies’ microstructure. They found a proliferation of floor concavities on the crystalline grains of the perovskite materials.

These concavities are proven to interrupt the structural continuity on the perovskite movie interface, serving as a hidden microstructure issue limiting the effectivity and stability of perovskite cells.

Then, the group took an modern step to take away the grain floor concavities by utilizing a surfactant molecule, tridecafluorohexane-1-sulfonic acid potassium, to govern the pressure evolution and ion diffusion through the formation of perovskite movies.

Accordingly, their ultimate perovskite cells demonstrated apparent enhancements in effectivity retention beneath standardized thermal biking, damp warmth, and maximum-power-point monitoring exams.

The article, titled “Elimination of grain surface concavities for improved perovskite thin-film interfaces,” has now been published in Nature Power. The work was a collaborative effort between Hong Kong Baptist College and Yale College.

“Structure and geometry of individual crystalline grains are the origin of the performance of perovskite semiconductors and solar cells. By unveiling the grain surface concavities, understanding their effects, and leveraging chemical engineering to tailor their geometry, we are pioneering a new way of making perovskite solar cells with efficiency and stability toward their limits,” mentioned Prof. Zhou, the corresponding writer of this work.

“We have been very intrigued by the surface concavities of perovskite grains once we have been utilizing atomic force microscopy to examine the structural details of perovskite films. These concavities are usually buried underneath the film bottom and easily be overlooked,” he added.

“Microstructure is of important significance for perovskite photo voltaic cells and different optoelectronic units, and might be extra advanced than standard supplies owing to the hybrid organic-inorganic traits of perovskite supplies.

“Under Prof. Zhou’s guidance, we are able to develop various novel characterization and data science approaches to gain insights into perovskite microstructure,” mentioned Zhang Yalan, a Ph.D. scholar in Prof. Zhou’s analysis group and a co-author of this work.