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Gas Sensing with Solar Cells: The Case of NH 3 Detection through Nanocarbon/Silicon Hybrid Heterojunctions. NANOMATERIALS 2020; 10:nano10112303. [PMID: 33233439 PMCID: PMC7700682 DOI: 10.3390/nano10112303] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/09/2020] [Accepted: 11/09/2020] [Indexed: 01/08/2023]
Abstract
Photovoltaic (PV) cells based on single-walled carbon nanotube (SWCNT)/silicon (Si) and multiwalled carbon nanotube (MWCNT)/Si junctions were tested under exposure to NH3 in the 0-21 ppm concentration range. The PV cell parameters remarkably changed upon NH3 exposure, suggesting that these junctions, while being operated as PV cells, can react to changes in the environment, thereby acting as NH3 gas sensors. Indeed, by choosing the open-circuit voltage, VOC, parameter as read-out, it was found that these cells behaved as gas sensors, operating at room temperature with a response higher than chemiresistors developed on the same layers. The sensitivity was further increased when the whole current-voltage (I-V) curve was collected and the maximum power values were tracked upon NH3 exposure.
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Dhall S, Mehta BR. Photo-sensing and photo-conversion investigation of single walled carbon nanotube-silicon interface: role of acid stimulation. NANO EXPRESS 2020. [DOI: 10.1088/2632-959x/abb362] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Freddi S, Achilli S, Soave R, Pagliara S, Drera G, De Poli A, De Nicola F, De Crescenzi M, Castrucci P, Sangaletti L. Dramatic efficiency boost of single-walled carbon nanotube-silicon hybrid solar cells through exposure to ppm nitrogen dioxide in air: An ab-initio assessment of the measured device performances. J Colloid Interface Sci 2020; 566:60-68. [PMID: 31986309 DOI: 10.1016/j.jcis.2020.01.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 12/19/2019] [Accepted: 01/13/2020] [Indexed: 11/16/2022]
Abstract
We observed a 73% enhancement of the power conversion efficiency (PCE) of a photovoltaic cell based on a single wall carbon nanotube/Si hybrid junction after exposing the device to a limited amount (10 ppm) of NO2 diluted in dry air. On the basis of a computational modeling of the junction, this enhancement is discussed in terms of both carbon nanotube (CNT) p-doping, induced by the interaction with the oxidizing molecules, and work function changes across the junction. Unlike studies so far reported, where the PCE enhancement was correlated only qualitatively to CNT doping, our study (i) provides a novel and reversible path to tune and considerably enhance the cell efficiency by a few ppm gas exposure, and (ii) shows computational results that quantitatively relate the observed effects to the electrostatics of the cell through a systematic calculation of the work function. These effects have been cross-checked by exposing the cell to reducing molecules (i.e·NH3) that resulted to be detrimental to the cell efficiency, consistently with the theoretical ab-initio calculations.
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Affiliation(s)
- Sonia Freddi
- Surface Science and Spectroscopy Lab @ I-Lamp, and Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, Brescia, Italy; Division of Molecular Imaging and Photonics, Department of Chemistry, KU Leuven, Celestijnenlaan 200F, 3001 Leuven, Belgium
| | - Simona Achilli
- Dipartimento di Fisica, Università di Milano, via Celoria 16, 20133 Milano, Italy
| | - Raffaella Soave
- Istituto di Scienze e Tecnologie Chimiche "Giulio Natta" SCITEC-CNR Via C. Golgi, 19- 20133 Milano, Italy
| | - Stefania Pagliara
- Surface Science and Spectroscopy Lab @ I-Lamp, and Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, Brescia, Italy
| | - Giovanni Drera
- Surface Science and Spectroscopy Lab @ I-Lamp, and Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, Brescia, Italy
| | - Andrea De Poli
- Surface Science and Spectroscopy Lab @ I-Lamp, and Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, Brescia, Italy
| | - Francesco De Nicola
- Graphene Labs, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova, Italy
| | | | - Paola Castrucci
- Dipartimento di Fisica, Università di Roma Tor Vergata, 00133 Roma, Italy
| | - Luigi Sangaletti
- Surface Science and Spectroscopy Lab @ I-Lamp, and Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, Brescia, Italy.
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Abstract
Single-wall carbon nanotubes (SWNTs) have been extensively explored as an ultrafast nonlinear optical material. However, due to the numerous electronic and morphological arrangements, a simple and self-contained physical model that can unambiguously account for the rich photocarrier dynamics in SWNTs is still absent. Here, by performing broadband degenerate and non-degenerate pump-probe experiments on SWNTs of different chiralities and morphologies, we reveal strong evidences for the existence of bandgap renormalization in SWNTs. In particularly, it is found that the broadband transient response of SWNTs can be well explained by the combined effects of Pauli blocking and bandgap renormalization, and the distinct dynamics is further influenced by the different sensitivity of degenerate and non-degenerate measurements to these two concurrent effects. Furthermore, we attribute optical-phonon bath thermalization as an underlying mechanism for the observed bandgap renormalization. Our findings provide new guidelines for interpreting the broadband optical response of carbon nanotubes.
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