Nanocrystalline lanthanum boride thin films by femtosecond pulsed laser deposition as efficient emitters in hybrid thermionic-photovoltaic energy converters

Year: 2020

Authors: Bellucci A., Mastellone M., Girolami M., Serpente V., Generosi A., Paci B., Mezzi A., Kaciulis S., Carducci R., Polini R., Orlando S., Santagata A., De Bonis A., Meucci M., Mercatelli L., Sani E., Trucchi D. M.

Autors Affiliation: CNR, ISM, Via Salaria Km 29-300, I-00015 Monterotondo, RM, Italy; Univ Roma La Sapienza, Dipartimento Sci Base & Applicate Ingn, Via A Scarpa 14, I-00161 Rome, Italy; CNR, ISM, Via Fosso Cavaliere 100, I-00133 Rome, RM, Italy; CNR, ISMN, Via Salaria Km 29-300, I-00015 Monterotondo, RM, Italy; Univ Roma Tor Vergata, Dipartimento Sci & Tecnol Chim, Via Ric Sci 1, I-00133 Rome, Italy; CNR, ISM, I-85050 Tito, PZ, Italy; Univ Basilicata, Dipartimento Sci, Via Ateneo Lucano 10, I-85100 Potenza, Italy; CNR, INO, Largo E Fermi 6, I-50125 Florence, FI, Italy.

Abstract: Lanthanum hexaboride (LaB6)-based thin films were successfully synthesized via femtosecond Pulsed Laser Deposition (fs-PLD) at room temperature and at high growth rate (>110 nm/min) for acting as electron and photon emitters in hybrid thermionic-photovoltaic devices applied in thermal-to-electrical energy conversion. The physical and chemical properties of the films were systematically investigated as a function of the most relevant deposition parameters (laser pulse repetition rate, pressure of the reactor, and deposition time) aimed at optimizing the material’s microstructure and functional optical and electronic properties. Specific growth conditions allowed for the achievement of thin films consisting of nanocrystalline LaB6 (10–20 nm grain-size) with enhanced spectral emissivity and low work function of (2.64 ± 0.03) eV, evaluated by thermionic emission measurements up to 1860 K, where a thermionic current density of 1.78 A cm−2 was measured. The obtained results demonstrate that fs-PLD represents a novel and rapid method for preparing efficient, and low-cost thermal electron emitters for innovative hybrid thermionic conversion devices operating at temperatures close to 2000 K.

Journal/Review: APPLIED SURFACE SCIENCE

Volume: 513      Pages from: 145829-1  to: 145829-9

More Information: The project thanks AMADEUS has received funds from the European Union´s Horizon 2020 research and innovation program, FET-OPEN action, under grant agreement 737054. The sole responsibility for the content of this publication lies with the authors. It does not necessarily reflect the opinion of the European Union. Neither the REA nor the European Commission are responsible for any use that may be made of the information contained therein.
KeyWords: Femtosecond pulsed laser deposition
Lanthanum hexaboride
Low work function
Thermionic energy conversion
Thin films
DOI: 10.1016/j.apsusc.2020.145829

Citations: 16
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