Near-field heterodyne transient grating (NF-HD-TG) responses of hematite (α-FeO) treated with cobalt phosphate (Co-Pi) were measured with the burn lasers inducing the depletion of the response by the removal of the trapped charge carriers in the target state, which is called charge carrier-selective heterodyne transient grating (CS-HD-TG) spectroscopic technique. We found that two distinct trap states co-existed in Co-Pi loaded on the surface of α-FeO. One of them named r-SS2, of which potential was similar to that of r-SS1 in the surface of α-FeO, acted as a recombination centre but could increase the lifetime of the trapped holes by the charge separation. We also revealed that the energetic position of the other (i-SS2), which has been regarded as the intermediate state for oxygen evolution reaction with low overpotential, was higher than that of i-SS1 in α-FeO but lower than those of r-SS1 and r-SS2.
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http://dx.doi.org/10.1002/cphc.202300894 | DOI Listing |
This article covers the in-vessel design of the SPARC interferometry diagnostic system, highlighting unique aspects of the systems design and port plug integration in preparation for "day-1" plasma operations as a critical diagnostic for density feedback control. An early decision for the diagnostic was to deploy two lasers in the infrared wavelength spectrum, allowing the system to have a higher optical throughput. The optimization of the in-vessel geometry for the diagnostic follows a similar approach, focusing on de-risking possible damage to the plasma facing optical components by moving them further from the plasma with an orientation that provides a greater possibility for protective features to be added.
View Article and Find Full Text PDFJ Chem Phys
November 2024
Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Aqueous interfaces containing organic/inorganic molecules are important in various biological, industrial, and atmospheric processes. So far, the study on the dynamics of interfacial molecules has been carried out with time-resolved vibrational sum-frequency generation (TR-VSFG) and time-resolved electronic sum-frequency generation (TR-ESFG) techniques. Although the ESFG probe is powerful for investigating interfacial photochemical dynamics of solute molecules by monitoring the electronic transition of transients or photoproducts at the interface, heterodyne detection is highly desirable for obtaining straightforward information, particularly in time-resolved measurements.
View Article and Find Full Text PDFNano Lett
August 2024
II. Physikalisches Institut, Universität zu Köln, Zülpicher Straße 77, Köln D-50937, Germany.
Using heterodyne transient grating spectroscopy, we observe a significant enhancement of exciton diffusion in a monolayer WSe stacked on graphene. The diffusion dynamics can be optically tuned within a few picoseconds by altering the photoexcited carrier density in graphene. The effective diffusion constant in initial picoseconds in the WSe/graphene heterostructure is (40.
View Article and Find Full Text PDFChemphyschem
September 2024
Department of Chemistry, Chungbuk National University, Chungdae-ro 1, Cheongju, Chungbuk, 28644, Korea.
We fabricated MAPbI perovskite thin films with ZnO on a glass substrate, in which a passivation layer (Phenethylammonium iodide (PEAI); p-methoxyphenethylammonium iodide (CHO-PEAI); 2-methoxyethylammonium iodide (MEAI)) was inserted between two layers. In order to understand the effect of the insertion of each passivation material on the transfer efficiency of the photo-generated electrons from MAPbI to ZnO, we observed the near-field heterodyne transient grating (NF-HD-TG) responses of each film and investigated the component arising from the recombination of the trapped electrons at the ZnO surface. Based on the accelerated recombination between photo-generated holes remaining in the MAPbI layer and surface-trapped electrons in ZnO and the increase in the number of the trapped electrons in ZnO when either CHO-PEAI or PEAI was applied, we successfully revealed that the charge transfer efficiency was enhanced by the insertion of the passivation materials including a benzene ring stabilizing the defect states.
View Article and Find Full Text PDFChemphyschem
May 2024
Department of Chemistry, Chungbuk National University, Chungdae-ro 1, Cheongju, Chungbuk 28644, Korea.
Near-field heterodyne transient grating (NF-HD-TG) responses of hematite (α-FeO) treated with cobalt phosphate (Co-Pi) were measured with the burn lasers inducing the depletion of the response by the removal of the trapped charge carriers in the target state, which is called charge carrier-selective heterodyne transient grating (CS-HD-TG) spectroscopic technique. We found that two distinct trap states co-existed in Co-Pi loaded on the surface of α-FeO. One of them named r-SS2, of which potential was similar to that of r-SS1 in the surface of α-FeO, acted as a recombination centre but could increase the lifetime of the trapped holes by the charge separation.
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