Descripción del proyecto
Documentación de las propiedades de las perovskitas orgánico-inorgánicas
La perovskita orgánico-inorgánica CH3NH3PbI3 ha surgido como un material excepcionalmente eficaz para la conversión fotoeléctrica. Este descubrimiento ha revelado su potencial en diversas aplicaciones, como la energía fotovoltaica, el láser, los diodos emisores de luz brillante y la disociación del agua. Además, tiene importantes implicaciones para las ciencias básicas. Investigaciones posteriores han demostrado que, cuando se expone a la luz blanca, los fotoelectrones de este compuesto permanecen en la banda de conducción y la resistividad de un solo cristal muestra un comportamiento metálico. Si estos portadores excitados tienen una vida lo bastante larga y una densidad suficientemente alta, podrían condensarse en un mar de Fermi. El equipo del proyecto PICOPROP, financiado por el Consejo Europeo de Investigación, pretende analizar este estado tan poco frecuente y documentar sus propiedades empleando técnicas de magnetotransporte y espectroscopia.
Objetivo
The recent discovery of the organo-inorganic perovskite CH3NH3PbI3 as very efficient material in photoelectric conversion is multifaceted: it turns out that this compound is promising not only in photovoltaics, but it is lasing, it gives bright light emitting diodes, promising in water splitting and we are persuaded that it can play an important role in basic sciences, as well.
We have recently realized that under white light illumination the photoelectrons, due to their very long recombination time, stay in the conduction band and the resistivity of a single crystal shows a metallic behavior. If the lifetime is sufficiently long and the density of these excited carrier is high enough they could condense into a Fermi sea. The project’s goal is to realize this highly unusual state and to document its properties by magneto-transport and spectroscopic techniques. We will check in our model compound the long-sought superconductivity of photo-excited carriers, extensively searched for in cuprates, if we could stabilize it by fine tuning the interactions by hydrostatic pressure under constant illumination.
The availability of high quality samples is primordial for this program. It turns out that CH3NH3PbI3 is ideal compound, it seems to be almost free of charged defects (its room temperature resistance is 5 orders of magnitude higher than that of Phosphorus doped Silicon at 1013 cm-3 doping concentration) and we can grow excellent single crystals of it. Furthermore, it has a flexibility in material design: one can vary all the constituents, and even the dimensionality by making layered materials with the main chemical motifs. A special effort will be devoted to tune the spin-orbit coupling by different elements, since this could be at the origin of the long recombination time of the photo-electrons.
We suspect that the highly tunable, clean and disorder-free doping obtained by shining light on these ionic crystals opens a new era in material discovery.
Ámbito científico
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Régimen de financiación
ERC-ADG - Advanced GrantInstitución de acogida
1015 Lausanne
Suiza