Two-Photon Sub-Bandgap Photocurrent in Surface-Nanotextured Black Diamond Films for Solar Energy Conversion
Two-photon sub-bandgap photocurrent (TPPC) is demonstrated in surface-nanotextured black diamond films fabricated by a two-step femtosecond laser treatment at an optimal total accumulated laser fluence of 5.0 kJ cm<sup>-2</sup>, unequally split between the two steps with a split ratio of 2:1. A broad intermediate band of electrically active deep-level defects, located at an energy distance of 1.83 eV from the conduction band, is experimentally observed by sub-bandgap spectral response evaluation in the 190-1000 nm wavelength range, allowing for a significant enhancement of quantum efficiency under photovoltaic conditions. This work represents the first experimental demonstration of TPPC in bulk materials with deep-level impurities conceived for intermediate-band solar cells and provides a solid physical interpretation of the operating principle of defect-engineered black diamond-based devices for solar energy conversion.
Authors
- Matteo Mastellone (ORCID: https://orcid.org/0000-0002-4291-6477)
- S. Salvatori (ORCID: https://orcid.org/0000-0002-6722-1794)
- D.M. Trucchi (ORCID: https://orcid.org/0000-0001-8278-4707)
- Sara Pettinato (ORCID: https://orcid.org/0000-0001-7093-3672)
- Valerio Serpente (ORCID: https://orcid.org/0000-0002-4137-1831)
- M. Girolami (ORCID: https://orcid.org/0000-0003-0063-3636)
- S. Orlando (ORCID: https://orcid.org/0000-0001-5116-3908)
- A. Bellucci (ORCID: https://orcid.org/0000-0001-7509-3318)
Institutions
- Institute of Structure of Matter (IT)
- CNR-IMIOT – Consiglio Nazionale delle Ricerche - Istituto di Metodologie Integrate per l’Osservazione della Terra (IT)
- University Niccolò Cusano (IT)
Publication Details
- Journal
- ACS Photonics
- Published
- 2025-08-11
- DOI
- https://doi.org/10.1021/acsphotonics.5c00722
- Citations
- 4
- Primary Topic
- Diamond and Carbon-based Materials Research
- Type
- article
- Field-Weighted Citation Impact
- 2.07
Funders
- FP7 Energy