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Hurley N, Bhandari B, Kamau S, Gonzalez Rodriguez R, Squires B, Kaul AB, Cui J, Lin Y. Selective CW Laser Synthesis of MoS 2 and Mixture of MoS 2 and MoO 2 from (NH 4) 2MoS 4 Film. Micromachines (Basel) 2024; 15:258. [PMID: 38398986 PMCID: PMC10892590 DOI: 10.3390/mi15020258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/04/2024] [Accepted: 02/07/2024] [Indexed: 02/25/2024]
Abstract
Very recently, the synthesis of 2D MoS2 and WS2 through pulsed laser-directed thermolysis can achieve wafer-scale and large-area structures, in ambient conditions. In this paper, we report the synthesis of MoS2 and MoS2 oxides from (NH4)2MoS4 film using a visible continuous-wave (CW) laser at 532 nm, instead of the infrared pulsed laser for the laser-directed thermolysis. The (NH4)2MoS4 film is prepared by dissolving its crystal powder in DI water, sonicating the solution, and dip-coating onto a glass slide. We observed a laser intensity threshold for the laser synthesis of MoS2, however, it occurred in a narrow laser intensity range. Above that range, a mixture of MoS2 and MoO2 is formed, which can be used for a memristor device, as demonstrated by other research groups. We did not observe a mixture of MoS2 and MoO3 in the laser thermolysis of (NH4)2MoS4. The laser synthesis of MoS2 in a line pattern is also achieved through laser scanning. Due to of the ease of CW beam steering and the fine control of laser intensities, this study can lead toward the CW laser-directed thermolysis of (NH4)2MoS4 film for the fast, non-vacuum, patternable, and wafer-scale synthesis of 2D MoS2.
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Affiliation(s)
- Noah Hurley
- Department of Physics, University of North Texas, Denton, TX 76203, USA; (N.H.); (B.B.); (S.K.); (R.G.R.); (B.S.); (J.C.)
| | - Bhojraj Bhandari
- Department of Physics, University of North Texas, Denton, TX 76203, USA; (N.H.); (B.B.); (S.K.); (R.G.R.); (B.S.); (J.C.)
| | - Steve Kamau
- Department of Physics, University of North Texas, Denton, TX 76203, USA; (N.H.); (B.B.); (S.K.); (R.G.R.); (B.S.); (J.C.)
| | - Roberto Gonzalez Rodriguez
- Department of Physics, University of North Texas, Denton, TX 76203, USA; (N.H.); (B.B.); (S.K.); (R.G.R.); (B.S.); (J.C.)
| | - Brian Squires
- Department of Physics, University of North Texas, Denton, TX 76203, USA; (N.H.); (B.B.); (S.K.); (R.G.R.); (B.S.); (J.C.)
| | - Anupama B. Kaul
- Department of Materials Science and Engineering, University of North Texas, Denton, TX 76203, USA;
- Department of Electrical Engineering, University of North Texas, Denton, TX 76203, USA
| | - Jingbiao Cui
- Department of Physics, University of North Texas, Denton, TX 76203, USA; (N.H.); (B.B.); (S.K.); (R.G.R.); (B.S.); (J.C.)
| | - Yuankun Lin
- Department of Physics, University of North Texas, Denton, TX 76203, USA; (N.H.); (B.B.); (S.K.); (R.G.R.); (B.S.); (J.C.)
- Department of Electrical Engineering, University of North Texas, Denton, TX 76203, USA
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Kamau S, Rodriguez RG, Jiang Y, Mondragon AH, Varghese S, Hurley N, Kaul A, Cui J, Lin Y. Enhanced Photoluminescence and Prolonged Carrier Lifetime through Laser Radiation Hardening and Self-Healing in Aged MAPbBr 3 Perovskites Encapsulated in NiO Nanotubes. Micromachines (Basel) 2023; 14:1706. [PMID: 37763869 PMCID: PMC10534348 DOI: 10.3390/mi14091706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2023] [Revised: 08/21/2023] [Accepted: 08/29/2023] [Indexed: 09/29/2023]
Abstract
Organic-inorganic perovskites hold great promise as optoelectronic semiconductors for pure color light emitting and photovoltaic devices. However, challenges persist regarding their photostability and chemical stability, which limit their extensive applications. This paper investigates the laser radiation hardening and self-healing-induced properties of aged MAPbBr3 perovskites encapsulated in NiO nanotubes (MAPbBr3@NiO) using photoluminescence (PL) and fluorescence lifetime imaging (FLIM). After deliberately subjecting the MAPbBr3@ NiO to atmospheric conditions for two years, the sample remains remarkably stable. It exhibits no changes in PL wavelength during UV laser irradiation and self-healing. Furthermore, exposure to UV light at 375 nm enhances the PL of the self-healed MAPbBr3@NiO. FLIM analysis sheds light on the mechanism behind photodegradation, self-healing, and PL enhancement. The results indicate the involvement of many carrier-trapping states with low lifetime events and an increase in peak lifetime after self-healing. The formation of trapping states at the perovskite/nanotube interface is discussed and tested. This study provides new insights into the dynamics of photo-carriers during photodegradation and self-healing in organic-inorganic perovskites.
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Affiliation(s)
- Steve Kamau
- Department of Physics, University of North Texas, Denton, TX 76203, USA; (S.K.); (R.G.R.); (Y.J.); (A.H.M.); (S.V.); (N.H.); (J.C.)
| | - Roberto Gonzalez Rodriguez
- Department of Physics, University of North Texas, Denton, TX 76203, USA; (S.K.); (R.G.R.); (Y.J.); (A.H.M.); (S.V.); (N.H.); (J.C.)
| | - Yan Jiang
- Department of Physics, University of North Texas, Denton, TX 76203, USA; (S.K.); (R.G.R.); (Y.J.); (A.H.M.); (S.V.); (N.H.); (J.C.)
| | - Araceli Herrera Mondragon
- Department of Physics, University of North Texas, Denton, TX 76203, USA; (S.K.); (R.G.R.); (Y.J.); (A.H.M.); (S.V.); (N.H.); (J.C.)
| | - Sinto Varghese
- Department of Physics, University of North Texas, Denton, TX 76203, USA; (S.K.); (R.G.R.); (Y.J.); (A.H.M.); (S.V.); (N.H.); (J.C.)
| | - Noah Hurley
- Department of Physics, University of North Texas, Denton, TX 76203, USA; (S.K.); (R.G.R.); (Y.J.); (A.H.M.); (S.V.); (N.H.); (J.C.)
| | - Anupama Kaul
- Department of Materials Science and Engineering, University of North Texas, Denton, TX 76203, USA;
- Department of Electrical Engineering, University of North Texas, Denton, TX 76203, USA
| | - Jingbiao Cui
- Department of Physics, University of North Texas, Denton, TX 76203, USA; (S.K.); (R.G.R.); (Y.J.); (A.H.M.); (S.V.); (N.H.); (J.C.)
| | - Yuankun Lin
- Department of Physics, University of North Texas, Denton, TX 76203, USA; (S.K.); (R.G.R.); (Y.J.); (A.H.M.); (S.V.); (N.H.); (J.C.)
- Department of Electrical Engineering, University of North Texas, Denton, TX 76203, USA
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Campbell E, Hasan MT, Gonzalez Rodriguez R, Akkaraju GR, Naumov AV. Doped Graphene Quantum Dots for Intracellular Multicolor Imaging and Cancer Detection. ACS Biomater Sci Eng 2019; 5:4671-4682. [DOI: 10.1021/acsbiomaterials.9b00603] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
| | | | | | - Giridhar R. Akkaraju
- Department of Biology, Texas Christian University, 2955 S University Drive, Fort Worth, Texas 76129, United States
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Garriott JC, Di Maio VJ, Rodriguez RG. Detection of cannabinoids in homicide victims and motor vehicle fatalities. J Forensic Sci 1986; 31:1274-82. [PMID: 3783102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A gas chromatographic/mass spectrometric (GC/MS) procedure is described for the detection and measurement of delta 9-tetrahydrocannabinol, 11-hydroxy-delta 9-tetrahydrocannabinol, and 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid in blood, or 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid in urine. About 50% of all homicide victims and motor vehicle drivers killed in Bexar County in 1985 were tested for the presence of cannabinoids. Of 130 homicides and 69 drivers tested, blood was analyzed primarily in all but 15 and 3 cases, respectively. In these latter cases, blood analyzed after urine was found to be positive. Of the homicide victims, 44 (34%), and of all drivers, 19 (28%), tested were positive for one or more of the cannabinoids. As a separate group, 16 motorcycle drivers tested had 38% positive as compared with 25% of the other vehicle drivers. Ethyl alcohol was present in 55% of the drivers, and in 63% of the homicide victims. Drugs other than alcohol or cannabinoids were found in 10% of the drivers, and in 12% of the homicide victims.
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