Computational and experimental scientists have joined forces to improve a technology emerging in solar energy: two-dimensional perovskite solar cells. The work was conducted within the framework of CINE.

Materials from the perovskite family are already used in highly efficient solar cells, but the new technology, still under development in research laboratories, is the use of very thin perovskite films, formed by layers a few tens of nanometers thick.

Each of these layers is composed of inorganic plates separated by organic spacers whose hydrophobic properties promise to increase the durability of perovskite solar cells by protecting them from moisture, which causes degradation. However, optimizing this technology requires a detailed understanding of the material’s behavior at the atomic scale.

In a recent study, computational scientists from IQSC-USP and IFSC-USP collaborated with experimental researchers from Unicamp specializing in perovskites to investigate how the properties of a two-dimensional perovskite change as a function of its thickness, determined by the number of layers that make up the film.

To achieve this, the team used simulations based on Density Functional Theory (DFT). The computational approach was chosen because it allows for a very precise analysis of the material’s properties at the atomic scale, in addition to significantly reducing the cost and time of research compared to experimental work.

“Theory allows us to understand the reasons behind phenomena at the atomic level and predict the behavior of new materials, while experimental expertise keeps us grounded, directing research toward results that can actually be applied and tested,” says doctoral student Israel Ribeiro about the collaboration that made this study possible. “This bridge between the computational and experimental realms is what accelerates the development of more efficient technologies,” adds Israel, who is the first author of the scientific paper reporting this work.

The simulation results revealed that, even in such thin films, changes in thickness significantly influence properties that are essential to the functioning of a solar cell. Therefore, adding or removing layers would allow for fine-tuning the device’s performance.

Published in the journal ACS Applied Energy Materials, the paper includes an insights section with practical guidelines for producing two-dimensional perovskites that meet the needs of the desired application.

The main one is the importance of finding the ideal balance in film thickness. Indeed, films with fewer layers absorb less light and have more difficulty to convert it into electricity. On the other hand, in thicker films, electrons and holes have more difficulty to move, reducing the solar cell’s efficiency.

“By mapping properties as a function of thickness, we offer a way for experimentalists to focus their efforts on the most promising configurations for a given application,” concludes Ribeiro.

The work was funded by FAPESP, Shell, and CNPq, in addition to strategic support from ANP.

Paper reference: Israel C. Ribeiro, Felipe D. Picoli, Pedro Ivo R. Moraes, André F. V. Fonseca, Luiz N. Oliveira, Ana Flávia Nogueira, Juarez L. F. Da Silva. Impact of Thin Film Thickness on the Structural, Energetic, and Optoelectronic Properties of Two-Dimensional FPEA2(MAn–1)PbnI3n+1 Perovskites. 2025, 8, 6, 3346–3359. https://pubs.acs.org/doi/10.1021/acsaem.4c02800

CINE members who participated in the work: Israel C. Ribeiro, Pedro Ivo R. Moraes, André F. V. Fonseca, Ana Flávia Nogueira, and Juarez L. F. Da Silva.