Recent Advances in the Stabilization of Metal Halide Perovskites

Dear Colleagues,

Affordable, reliable, sustainable, and renewable energy solutions are one of the most dramatic needs of our world. In this respect, photovoltaics (PV) is gaining momentum, tailoring the relationship between solar cell (SC) performance (PCE) and device costs in the direction of making this technology accessible to all. Optimizing the light harvesting in a SC through the choice of an appropriate photo-active layer (AL) is of paramount importance for increasing PCE. Modern PV points to metal halide perovskites as one of the most promising classes for AL materials due to their efficient solar-power conversion, low cost, and simple manufacturing process.

Despite advances in compositional engineering, perovskite solar cells (PSCs) are still deficient in long-term stability and PCE because of defects, phase transitions, and inhomogeneous halide distribution in the perovskite film. The non-uniform energy landscape leads to accelerated halide segregation through photogenerated hole trapping by iodide-rich, low-bandgap domains. Homogenizing the composition distribution remains a promising strategy to suppress bulk recombination. In 1.5 eV PSCs suitable for single-junction applications, introducing rubidium (Rb) has been established to be effective approach to homogenize perovskite growth, eliminate detrimental impurities, and stabilize photo-active α-phases. To date, wide-bandgap perovskites are composed of a mixed halide at the X-site and a combination of formamidinium (FA), methylammonium (MA), and cesium (Cs) at the A-site to achieve the desired bandgap, phase stability, and low defect density.

Low-dimensional (2D) or layered hybrid perovskites are gaining increasing attention due to their superior stability. They are based on organic ammonium cation templating layers of hybrid perovskites, whose stability is attributed to the hydrophobicity of the organic spacers and their ability to attenuate ion migration. Coating 3D perovskites with a 2D layer could also be an effective solution to improve the long-term stability of PSCs.

In this Special Issue, we are looking for high-quality experimental and theoretical articles that can contribute to these topics, helping the PV community to take a fundamental step in the creation of competitive PSCs, bridging the gap between academia and industry.

We are also interested in possible new strategies for stabilizing metal halide perovskites, such as different low-dimensionality phases. Systematic work on the creation of open-source theoretical and experimental databases will also be highly appreciated, with the idea of laying the foundations for the training of accurately machine-learned interatomic potentials.

Dr. Virginia Carnevali
Dr. Mingyang Wei
Guest Editors

Dr. Vladislav Sláma
Dr. Lorenzo Agosta
Guest Editor Assistants

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 250 words) can be sent to the Editorial Office for assessment.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Crystals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2100 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.