H2020Индивидуална стипендия2021–2023

PhoMOFs · Accessing Electron-Phonon interactions of two-dimensional Metal Organic Frameworks by Ultrabroadband Terahertz Spectroscopy based on the Spintronic Trilayer Emitter

„Хоризонт 2020“ — Действия „Мария Склодовска-Кюри“

Период: 2021-05-01 → 2023-08-20
Финансиране от ЕС: 160 932 €
Участници: 1
Схема: MSCA-IF

Линиите свързват координатора с партньорите.

Накратко на български

Метал-органичните рамки (MOFs) се изследват чрез терахерцова спектроскопия, за да се разбере как трептенията на кристалната решетка влияят върху движението на електроните. Това помага да се разбере връзката между химичния състав и проводимостта на тези материали за бъдещи приложения.

Този кратък обзор е генериран от изкуствен интелект

Кратко обяснение, генерирано от езиков модел по текста на CORDIS. Оригиналът е по-долу.

Резултати накратко

Accessing Electron-Phonon interactions of two-dimensional Metal Organic Frameworks by Ultrabroadband Terahertz Spectroscopy based on the Spintronic Trilayer Emitter

The recent discovery of semiconducting MOFs, has ignited the interest on these hybrid materials, with tailor-made properties, as alternatives for applications where long-range charge transport is demanded. However, for tailoring the semiconductive properties of a MOF for a specific application, we need a deep understanding of the relationships between the structure and the chemistry and its charge transport properties. One of the most important questions is the identification of phonons in MOFs and how these affect the charge carrier transport and ultimately, whether they can be tailored on-demand, by introducing changes in the chemistry of the material. The host group introduced a powerful non-contact AC technique, namely the Time Resolved THz Spectroscopy (TRTS) technique, for studying carrier dynamics in MOFs. In a TRTS experiment, an optical pulse is used to excite the electrons of the semiconducting material from the valence band to the conduction band. Then, a THz pulse transverses the material with an adjustable time delay and due to the sensitivity of THz radiation to free charge carriers, it allows accessing the sample’s complex conductivity in the AC limit, providing precious information on the charge transfer mechanism, charge carrier density and mobility. However, one of the most important drawbacks for the study of optical phonons using traditional electro-optic crystals for the THz emission is their limited bandwidth, usually covering frequency windows of not more than ~0.1-2THz. This limits substantially the amount of information one can harvest from TRTS experiments, since it does not allow the characterization of IR-active lattice vibrations (phonons), which usually extend in the frequency range between 60 cm-1 and 500 cm-1. Here, I proposed the use of the recently developed Spintronic Trilayer Emitter (STE) ultrabroadband THz source, in order to achieve the desirable large bandwidth. Its simple geometry includes a ferromagnetic (FM) thin layer, enclosed between two non-magnetic (NM) layers. Upon laser excitation an ultrashort THz pulse (~100-200fs) is emitted, covering frequencies between ~0.3 and 30 THz. The main objective of PhoMOFs was to introduce the ultrabroadband THz STE for the investigation of phonons and their interplay with charge carrier dynamics and transport properties in the rapidly emerging field of 2D semiconducting MOFs. We aimed at establishing neat correlations between chemistry and structure of the material and its electronic structure, conductivity and carrier mobility.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз

Цел на проекта

The recent discovery of high-mobility band-like charge transport in two-dimensional semiconducting Metal Organic Frameworks (2D-MOFs), represents a breakthrough that paves the way for developing novel highly tailorable optoelectronic devices. However, for harvesting the benefits of these materials, it is still required a deeper understanding on the interplay between MOF structure and chemical composition with electronic structure, conductivity, doping and charge carrier mobility. Among the current methods used to characterize charge transport in MOFs, Time-Resolved Terahertz (THz) Spectroscopy (TRTS) stands out, owing to the fact that it is a non-contact technique, with sub-ps resolution, and capable of disentangling the conductivity, doping and mobility of a given sample in the AC limit. Despite powerful, current TRTS setups do have a limitation connected with a small frequency bandwidth of state-of-the-art THz probes (typically limited to 0.2-2 THz). In this project, I will introduce a novel THz Spintronic Trilayer Emitter (STE), holding a bandwidth that is ~15 times broader than that of traditional THz sources, for investigating charge transport in the recently discovered semiconducting MOFs. The STE ultrabroadband frequency window, linked to an ultrashort pulse time duration, will allow for the first time characterizing phonons and their interplay with free carriers (which limit sample´s mobility) as a function of sample chemistry and structure. This powerful approach will ultimately lead to unequivocally establishing connections between structure and charge transport properties in these promising and technologically relevant materials.

Оригинален текст от CORDIS (на английски).

Участници

FUNDACION IMDEA NANOCIENCIA · MadridКоординаторИспания