Nav: Home

Materials scientists of Lomonosov MSU proposed a novel approach for obtaining films for solar cells

July 23, 2018

Materials scientists from Lomonosov Moscow State University explained the laws of dissolution and crystallization of hybrid perovskites and proposed a novel approach for obtaining films for solar cells

Scientists of the Lomonosov Moscow State University, Department Materials Science explained the key mechanisms of interaction of hybrid perovskites with solvents and suggested new approaches to obtain perovskite light-absorbing layers for thin-film solar cells from weakly coordinating aprotic solvents.

The results of the study have been recently published in the high-rating journal Chemistry of Materials.

A team of scientists at the Department of Materials Science and the Department of Chemistry of Lomonosov Moscow State University conducts an intensive work in the field of perovskite photovoltaics, which is now the most rapidly developing area in materials science.

So far, thin-film solar cells based on hybrid perovskites have already reached an efficiency of 23.2%, surpassing traditional solar cells based on silicon. The light-absorbing layer of perovskite in such devices can be obtained by simpler and cheaper solution methods. In a new study, performed in the laboratory of "New Materials for Solar Energetics" under the supervision of the head of the laboratory, Ph.D. Alexey Tarasov, young scientists studied the processes of perovskite crystallization from a solvent with unusual properties - gamma-butyrolactone (GBL).

"In our laboratory we develop new innovative non-solvent methods for obtaining solar cells but also pay great attention to the fundamental aspects of perovskite chemistry. This is a traditional characteristic trait of the materials science school of Lomonosov Moscow State University, which distinguishes us from most of the world's groups", - said Alexey Tarasov.

There are two solvents which are usually used to prepare perovskite thin films from solutions: dimethylsulfoxide and dimethylformamide. However, our earlier work showed that crystallization from these solvents proceeds through formation of intermediate compounds - crystallosolvates, which can impair the morphology and functional properties of the perovskite layer.

As a solvent for perovskite, GBL has been also known. In particular, it exhibits so-called retrograde solubility (solubility of perovskite in it decreases with the increase of temperature). This feature was widely used by researchers to produce single crystals, whereas the attempts to obtain a thin film resulted in the formation of separated individual crystallites on a substrate. For a long time, this unusual behavior of perovskite solutions in GBL has remained obscure. It was believed that the perovskite-GBL interaction is weak enough that it does not even form solvates with it (explain). However, scientists discovered that there are at least three types of perovskite crystals with GBL, and some of them have a unique cluster structure. It became clear that the equilibrium in perovskite solutions in GBL is much more complicated than previously expected.

"We have established that perovskite dissolves at room temperature with the formation of such clusters, and upon heating they decompose to small complexes. This leads to supersaturation and precipitation of perovskite from solution in the form of single crystals. We showed that it was theprecipitation of a cluster adduct instead of perovskite that prevented the formation of thin films from this solvent. Based on the understanding of the processes that occur during the dissolution of perovskite in GBL, we proposed approaches that bypass the formation of clusters and results in perovskite crystallization. Consequently, we obtained high-quality films from GBL for the first time. This is an excellent example of the practical application of fundamental chemical knowledge for the solution of materials science problems - just what is generally called fundamental material science throughout the world", - concluded Alexey Tarasov.
The study was conducted in cooperation with scientists from the Kurchatov Center for Synchrotron Radiation and Nanotechnology (KCSRN).

Lomonosov Moscow State University

Related Chemistry Articles:

Better chemistry through tiny antennae
A research team at The University of Tokyo has developed a new method for actively controlling the breaking of chemical bonds by shining infrared lasers on tiny antennae.
Chemistry in motion
For the first time, researchers have managed to view previously inaccessible details of certain chemical processes.
Researchers enrich silver chemistry
Researchers from Russia and Saudi Arabia have proposed an efficient method for obtaining fundamental data necessary for understanding chemical and physical processes involving substances in the gaseous state.
The chemistry behind kibble (video)
Have you ever thought about how strange it is that dogs eat these dry, weird-smelling bits of food for their entire lives and never get sick of them?
Top 10 chemistry start-ups
Starting a new chemistry-based company is one part discovery, one part risk.
More Chemistry News and Chemistry Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Erasing The Stigma
Many of us either cope with mental illness or know someone who does. But we still have a hard time talking about it. This hour, TED speakers explore ways to push past — and even erase — the stigma. Guests include musician and comedian Jordan Raskopoulos, neuroscientist and psychiatrist Thomas Insel, psychiatrist Dixon Chibanda, anxiety and depression researcher Olivia Remes, and entrepreneur Sangu Delle.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...