MATTEO MASTELLONE

PhD

PhD program:: XXXIII



Thesis title: Photon-Enhanced Thermionic Emission cathodes for concentrated solar energy conversion

The research activities at the basis of this doctoral project were focused on the design, characterization and fabrication of innovative high-temperature solar cells based on the concept of photon-enhanced thermionic emission (PETE). PETE is a conversion mechanism that exploits both photo-electric and thermionic emission concepts, and that allows to overcome the limitations of standard junction cells when operating at high temperatures. The proposed solar cell concept, which implies a direct application in conversion of concentrated solar radiation and energy recovery from high-temperature thermal sources, is made entirely of highly-engineered synthetic diamond, can operate up to about 800 °C and allows the combination of an additional conversion stage or energy storage system. High potential conversion efficiencies (> 40%), scalability typical of solid-state devices, non-toxicity for human health represent the main key advantages with respect to conventional technologies. The core of this doctoral project is represented by the development of single-crystal synthetic diamond PETE photocathodes (including also attempts with 6H-SiC), on which an innovative scientific concept is applied: the defect engineering of a semiconductor that does not natively interact with solar radiation (i.e. diamond, with an energy bandgap of 5.5 eV, is known to be solar-blind). The project foresaw the employment of technologies able to completely modify the optical and photoelectronic properties, turning the material from transparent to highly absorbing, but maintaining the excellent charge transport capability. To this end, this doctorate thesis reports on a variety of experimental investigations aimed mainly at advancing the understanding of fundamental processes of surface defect engineering, performed by inducing the formation of periodic surface nanotexturing through the use of ultra-short pulsed lasers. Furthermore, since the ultimate aim is to develop an original all-diamond PETE photo-cathode, efforts were also directed at the optimization of the thermionic emission capabilities of diamond. In conclusion, the proof-of-concept of high-temperature solar cell proposed in this thesis should be considered exemplificative of the controlled and effective defect engineering strategy, which can be extendable for future development of a new class of ultra-wide bandgap optoelectronic devices.

Research products

  • 11573/1179164 - 2018 - Investigation of work function and chemical composition of thin films of borides and nitrides (01a Articolo in rivista)
    MASTELLONE, MATTEO
  • 11573/1179160 - 2018 - Transport properties of photogenerated charge carriers in black diamond films (01a Articolo in rivista)
    MASTELLONE, MATTEO
  • 11573/1179139 - 2018 - Optical characterization of double-nanotextured black diamond films (01a Articolo in rivista)
    MASTELLONE, MATTEO
  • 11573/1179583 - 2017 - Surface texturing of CVD diamond assisted by ultrashort laser pulses (01g Articolo di rassegna (Review))
    MASTELLONE, MATTEO
  • 11573/1341232 - 2019 - Reproducibility analysis of diamond pixel detectors for large ionizing radiation fields (01a Articolo in rivista)
    MASTELLONE, MATTEO
  • 11573/1341229 - 2019 - Lanthanum (oxy)boride thin films for thermionic emission applications (01a Articolo in rivista)
    MASTELLONE, MATTEO
  • 11573/1341241 - 2019 - Electrical conductivity of double textured black diamond films from RT to 800 K (01a Articolo in rivista)
    MASTELLONE, MATTEO
  • 11573/1421443 - 2020 - Enhanced selective solar absorption of surface nanotextured semi-insulating 6H–SiC (01a Articolo in rivista)
    MASTELLONE, MATTEO
  • 11573/1421450 - 2020 - Photovoltaic anodes for enhanced thermionic energy conversion (01f Lettera, Nota)
    MASTELLONE, MATTEO
  • 11573/1493576 - 2021 - Dielectric micro- and sub-micrometric spacers for high-temperature energy converters (01a Articolo in rivista)
    MASTELLONE, MATTEO
  • 11573/1493592 - 2020 - Femtosecond-laser nanostructuring of black diamond films under different gas environments (01a Articolo in rivista)
    MASTELLONE, MATTEO
  • 11573/1493584 - 2021 - Upgrade and present limitations of solar thermionic-thermoelectric technology up to 1000 K (01a Articolo in rivista)
    MASTELLONE, MATTEO
  • 11573/1493601 - 2021 - Combined electrical resistivity-electron reflectivity measurements for evaluating the homogeneity of hydrogen-terminated diamond surfaces (01a Articolo in rivista)
    MASTELLONE, MATTEO
  • 11573/1493545 - 2020 - All-carbon THz components based on laser-treated diamond (01a Articolo in rivista)
    MASTELLONE, MATTEO
  • 11573/1493553 - 2020 - Nanocrystalline lanthanum boride thin films by femtosecond pulsed laser deposition as efficient emitters in hybrid thermionic-photovoltaic energy converters (01a Articolo in rivista)
    MASTELLONE, MATTEO
  • 11573/1493559 - 2020 - Ultra-thin films of barium fluoride with low work function for thermionic-thermophotovoltaic applications (01a Articolo in rivista)
    MASTELLONE, MATTEO
  • 11573/1493567 - 2020 - Improving the performance of printable carbon electrodes by femtosecond laser treatment (01a Articolo in rivista)
    MASTELLONE, MATTEO
  • 11573/1493564 - 2020 - Work function and negative electron affinity of ultrathin barium fluoride films (01a Articolo in rivista)
    MASTELLONE, MATTEO
  • 11573/1493535 - 2021 - Novel concepts and nanostructured materials for thermionic-based solar and thermal energy converters (01a Articolo in rivista)
    MASTELLONE, MATTEO

© Università degli Studi di Roma "La Sapienza" - Piazzale Aldo Moro 5, 00185 Roma