• Nijenborgh3, Gebouw 5118, ruimte 0051

    9747 AG Groningen

    Netherlands

Personal profile

Biosketch

Maria Antonietta Loi studied physics at the University of Cagliari in Italy where she received the PhD in 2001 for a thesis on Photoexcitations and Interchain Interactions in Conjugated Oligomers and Polymers which was carried out in the group of Prof. G. Bongiovanni and A. Mura. In the same year she joined the Linz Institute for Organic Solar cells, of the University of Linz, Austria as a postdoctoral fellow. Later she worked as researcher at the Institute for Nanostructured Materials of the Italian National Research Council in Bologna, Italy. In 2006 she became assistant professor and Rosalind Franklin Fellow at the Zernike Institute for Advanced Materials of the University of Groningen, The Netherlands. She is now full professor in the same institution and chair of the Photophysics and OptoElectronics group.

She has published more than 240 peer-reviewed articles on photophysics and optoelectronics of different types of materials. The main interest is unravelling the properties of novel semiconductors and to tune their properties to fabricate highly performing optoelectronic devices (Solar cells, LEDs, Photodetectros etc.)

In 2013 she has received an ERC Starting Grant and in 2022 and ERC Advanced Grant from the European Research Council. She currently serves as deputy editor in chief of Applied Physics Letters and she is member of the international advisory board of several international journals in physics and materials physics (Advanced Materials, Advance functional Materials, Materials Horizons, ACS Materials Letters , etc..). In 2018 she received the Physicaprijs from the Dutch physics association for her outstanding work on organic-inorganic hybrid materials. In 2020 she became fellow of the American Physical Society. In 2022 she became fellow of the Dutch Academy of Science (KNAW), of the European Academy of Science (EURASC) and fellow of the Fellow of the Royal Society of Chemistry.

  1. Kahmann, E. K. Tekelenburg, H. Duim, M. E. Kamminga, M. A. Loi “Extrinsic nature of the broad photoluminescence in lead iodide-based Ruddlesden–Popper perovskites” Nat. Commun. 11, 2344 (2020). Cited 74 time.

Two-dimensional metal halide perovskites of Ruddlesden–Popper type have recently moved into the centre of attention of perovskite research due to their potential for light generation and for stabilisation of their 3D counterparts. The photoluminescence spectra of this class of materials often shows a broad emission next to the excitonic peak, it has become widespread in the field to attribute the broad luminescence with a large Stokes shift to self-trapped excitons, forming due to strong carrier–phonon interactions in these compounds. Contrarily, by investigating the behaviour of two types of lead-iodide based single crystals, we here highlight the extrinsic origin of their broad band emission. As shown by below-gap excitation, in-gap states in the crystal bulk are responsible for the broad emission. With this insight, we further the understanding of the emission properties of low-dimensional perovskites and question the generality of the attribution of broad band emission in metal halide perovskite and related compounds to self-trapped excitons.

  1. Shao, J. Liu, G. Portale, H.-H. Fang, G. R. Blake, G. H. ten Brink, L. J. A. Koster, and M. A. Loi, “Highly Reproducible Sn-Based Hybrid Perovskite Solar Cells with 9% Efficiency” Adv. Energy Mater., 8, 1702019 (2018). Top 1% of the academic field of Materials Science. Cited 701 times

The low power conversion efficiency (PCE) of tin-based hybrid perovskite solar cells (HPSCs) is mainly attributed to the high background carrier density due to a high density of intrinsic defects such as Sn vacancies and oxidized species (Sn4+) that characterize Sn-based HPSCs. Here we reports on the successful reduction of the background carrier density by more than one order of magnitude by depositing near-single-crystalline formamidinium tin iodide (FASnI3) films with the orthorhombic a-axis in the out-of-plane direction. Using these highly crystalline films, obtained by mixing a very small amount (0.08 m) of layered (2D) Sn perovskite with 0.92 m (3D) FASnI3, for the first time a PCE as high as 9.0% in a planar p–i–n device structure is achieved. These devices display negligible hysteresis and light soaking, as they benefit from very low trap-assisted recombination, low shunt losses, and more efficient charge collection. This represents a 50% improvement in PCE compared to the best reference cell based on a pure FASnI3 film using SnF2 as a reducing agent. Moreover, the 2D/3D-based HPSCs show considerable improved stability due to the enhanced robustness of the perovskite film compared to the reference cell. This work was able to attract a large number of scientists towards this topic, revitalizing the activities on Sn-based metal halide perovskites, which were till then stagnant.

  1. -H. Fang, S. Adjokatse, S. Shao, J. Even, M. A. Loi, “Long-lived Hot-carrier Light Emission and Large Blue Shift in Formamidinium Tin Triiodide Perovskites” Nature Comm. 9, Article #: 243 (2018). Cited 171 times.

A long-lived hot carrier population is critical in order to develop working hot carrier photovoltaic devices with efficiencies exceeding the Shockley–Queisser limit. Here, we report photoluminescence from hot-carriers with unexpectedly long lifetime (a few ns) in formamidinium tin triiodide. This is the longest lifetime ever reported in any semiconductor. An unusual large blue shift of the time-integrated photoluminescence with increasing excitation power (150 meV at 24 K and 75 meV at 293 K) is displayed. On the basis of the analysis of energy-resolved and time-resolved photoluminescence, we posit that these phenomena are associated with slow hot carrier relaxation and state-filling of band edge states. These observations are both important for our understanding of lead-free hybrid perovskites and for an eventual future development of efficient lead-free perovskite photovoltaics.

 

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