HSE Scientists Develop Method to Stabilise Iodine in Solar Cells
Scientists at HSE MIEM, in collaboration with colleagues from China, have developed a method to improve the durability of perovskite solar cells by addressing iodine loss from the material. The researchers introduced quaternary ammonium molecules into the perovskite structure; these molecules form strong electrostatic pairs with iodine ions, effectively anchoring them within the crystal lattice. As a result, the solar cells retain more than 92% of their power after a thousand hours of operation at 85°C. The study has been published in Advanced Energy Materials.
Perovskites are materials with a specific crystal structure in which lead and halogen atoms (such as iodine) are combined with small organic or inorganic ions. This crystal lattice absorbs light efficiently and converts it into electricity. Over the past decade, perovskite solar cells have evolved from laboratory experiments into a major area of solar energy research. They can potentially be manufactured at a lower cost than silicon-based cells and have nearly matched them in terms of efficiency.
Iodine-based perovskites achieve efficiencies of over 26%, delivering the best performance among perovskite materials. This is because their energy structure is well suited to absorbing sunlight and capturing a large fraction of the incoming radiation. Charge carriers in these crystals have longer lifetimes, can travel greater distances, and suffer fewer losses from structural defects, which minimises undesirable charge recombination. However, iodide perovskites also have a drawback: under prolonged exposure to light and heat, their crystal lattice loses iodine, leading to erosion of the metal electrodes. As a result, the solar cell gradually deteriorates and its efficiency declines.
Previous attempts to address this issue have focused on strengthening the crystal structure or introducing molecules that bind iodine through hydrogen bonds. However, these bonds are not strong enough to retain iodine effectively during prolonged device operation. A more logical approach would be to use stronger electrostatic interactions, in which positively charged molecules firmly bind negatively charged iodine ions. Until now, however, it has been unclear how to incorporate such molecules into the perovskite crystal lattice without disrupting its structure.
In a new study, scientists from HSE MIEM, East China Normal University, Hengyang Normal University, and Ningbo University have developed a method to electrostatically retain iodine within the perovskite structure, significantly enhancing the resistance of solar cells to prolonged photothermal stress.
First, the researchers carried out theoretical calculations to identify molecules that could most effectively bind triiodide anions (I₃⁻). Quaternary ammonium compounds—molecules in which the nitrogen atom is fully surrounded by hydrocarbon groups—proved to be the most effective. This configuration enables strong confinement of triiodide ions, and subsequent experiments therefore employed tetrabutylammonium iodide (TBAI).
In the experimental phase, the researchers added TBAI to the solution used to form perovskite films and compared the resulting films with control samples prepared without additives. Films containing TBAI preserved their structural integrity and chemical stability under photothermal conditions, whereas the controls gradually degraded. This difference was evident from measurements of metallic lead, a marker of perovskite degradation: after 250 hours of photothermal exposure, its concentration in the modified films remained nearly unchanged, while in the control films it increased by approximately 1.5 times. In addition, the presence of TBAI almost completely suppressed the migration of iodine and copper between layers.
The researchers then tested full-scale solar cells. The addition of TBAI not only prevented degradation but also improved the properties of the material: the perovskite grains became larger and more ordered, the density of defects decreased, and the power conversion efficiency increased from 24.14% to 26.23%. For state-of-the-art perovskite devices operating close to their physical limits, such an improvement is substantial. TBAI also notably enhanced device stability: after 1,000 hours of operation at 85 °C, cells containing TBAI retained 92.5% of their initial efficiency, whereas the control device degraded to 43.8% after just 288 hours.
The authors hope that this approach to regulating electrostatic interactions in perovskites will contribute to the development of more durable solar cells.
Andrey Vasenko
'In theory, this approach could be applied to other types of halide perovskites, including materials in which iodine is combined with bromine. This would enable the development of solar panels that combine high efficiency with thermal stability,' comments Prof. Andrey Vasenko of HSE MIEM.
The study was carried out as part of the research project 'Engineering of Highly Efficient and Stable Perovskite Solar Cells.'
See also:
HSE Experts Reveal Low Accuracy of Technology Forecasts in Transportation
HSE researchers evaluated the accuracy of technology forecasts in the transportation sector over the past 50 years and found that the average accuracy rate does not exceed 25%, with the lowest accuracy observed in aviation and rail transport. According to the scientists, this is due to limitations of the forecasting method and the inherent complexities of the sector. The study findings have been published in Technological Forecasting and Social Change.
Wearable Device Data and Saliva Biomarkers Help Assess Stress Resilience
A team of scientists, including researchers from HSE University, has proposed a method for assessing stress resilience using physiological markers derived from wearable devices and saliva samples. The participants who adapted better to stress showed higher heart rate variability, higher zinc concentrations in saliva, and lower potassium levels. The findings were published in the Journal of Molecular Neuroscience.
HSE Unveils Anthropomorphic Courier Robot
From April 1 to 3, 2026, the Fourth Robotics Festival took place, with the HSE Faculty of Computer Science acting as the main organiser. The event featured the presentation of the anthropomorphic courier robot Arkus. The humanoid was introduced by the Institute for Robotic Systems, established jointly by HSE University and the EFKO Group of Companies.
When Circumstances Are Stronger Than Habits: How Financial Stress Affects Smoking Cessation
HSE researchers have found that the likelihood of quitting smoking rises with increasing financial struggles. While low levels of financial difficulties do not affect smoking behaviour, moderate financial stress can increase the probability of quitting by 13% to 21%. Responses to high financial stress differ by gender: men are almost 1.5 times more likely to give up cigarettes than under normal conditions, whereas no significant effect is observed on women’s decisions to quit smoking. These conclusions are based on data from the Russia Longitudinal Monitoring Survey (RLMS-HSE) for 2000–2023 and have been published in Monitoring of Public Opinion: Economic and Social Changes.
HSE Researchers Propose New Method of Verbal Fluency Analysis for Early Detection of Cognitive Impairment
Researchers from the HSE Center for Language and Brain and the Mental Health Research Centre have proposed a new method of linguistic analysis that enables the distinction between normal and pathological ageing. Using this approach, they showed that patterns in patients’ word choices during verbal fluency tests allow clinicians to more accurately differentiate clinically significant impairments from subjective memory complaints. Incorporating this type of analysis into clinical practice could improve the accuracy of early dementia diagnosis. The results have been published in Applied Neuropsychology: Adult.
How the Brain Processes a Word: HSE Researchers Compare Reading Routes in Adults and Children
Researchers from the HSE Center for Language and Brain used magnetoencephalography to study how the brains of adults and children respond to words during reading. They showed that in children the brain takes longer to process words that are frequently used in everyday speech, while rare words and pseudowords are processed in the same way—slowly and in parts. With age, the system is reorganised: high-frequency words shift to a fast route, whereas new letter combinations are still analysed slowly. The study was published in the journal Psychophysiology.
How Neural Networks Detect and Interpret Wordplay: New Insights from HSE Researchers
An international team including researchers from the HSE Faculty of Computer Science has presented KoWit-24, an annotated dataset of 2,700 Russian-language Kommersant news headlines containing wordplay. The dataset enables an assessment of how artificial intelligence detects and interprets wordplay. Experiments with five large language models show that even advanced systems still make mistakes, and that interpreting wordplay is more challenging for them than detecting it. The results were presented at the RANLP conference; the paper is available on Arxiv.org, and the dataset and the code for reproducing the experiments are available on GitHub.
HSE Economists Find That Auction Prices Depend on Artist’s Life Story
Researchers from the Centre for Big Data in Economics and Finance at the HSE Faculty of Economic Sciences have found that facts from an artist’s life are statistically significant in pricing a painting, alongside such traditional characteristics as the material, the size of the canvas, or the presence of the artist’s signature. This conclusion is based on an analysis of prices for 15,000 works by 158 artists sold since 1999 by the major auction houses Sotheby’s and Christie’s. The article has been published in the journal Empirical Studies of the Arts.
HSE Physicists Propose Unified Theory for Describing Electric Double Layer
To develop more efficient batteries and catalysts, it is essential to understand the processes occurring at the metal–solution interface in the electric double layer (EDL). Physicists at HSE MIEM have proposed a unified theoretical model of the EDL that simultaneously accounts for selective adsorption of ions on the surface and partial charge transfer between ions and the metal—phenomena that had previously been described separately. The model’s predictions are consistent with experimental data. In the future, it may be used in the development of batteries, supercapacitors, and catalysts. The study has been published in Electrochimica Acta.
HSE Researchers Experimentally Demonstrate Positive Effects of Urban Parks on the Brain
Scientists at HSE University have investigated the effect of parks on the cognitive and emotional resources of city dwellers. The researchers compared brain electrical activity in 30 participants while they watched videos of walks through parks and along busy highways. The results showed that green urban environments with trees produce a consistent effect across individuals, helping the brain calm down and relax. By contrast, walks along busy streets were found to be distracting. The findings have been published in Scientific Reports.