Scanning tunneling microscopy (STM) images taken on a freshly cleaved anatase TiO2(101) sample show an almost perfect surface with very few subsurface impurities and adsorbates. Surface oxygen vacancies are not typically present but can be induced by electron bombardment. In contrast, a reduced anatase (101) crystal shows isolated as well as ordered intrinsic subsurface defects in STM, consistent with density functional theory (DFT) calculations which predict that O vacancies (V_{O}'s) at subsurface and bulk sites are significantly more stable than on the surface.
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http://dx.doi.org/10.1103/PhysRevLett.102.106105 | DOI Listing |
In response to the growing need for detecting subsurface defects at the hundred-nanometer scale, this study introduces what we believe to be a novel dark field through-focus scanning optical microscopy (DF-TSOM) technique. Subsurface defect samples were prepared with a depth of 100 µm and diameters of 1 µm, 0.4 µm, 0.
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January 2025
Engineering Research Center of Electronic Information Materials and Devices (Ministry of Education), Guangxi Key Laboratory of Information Materials, School of Materials Science and Engineering, Guilin University of Electronic Technology, Guilin, 541004, China.
In recent years, carbon-based printable mesoscopic perovskite solar cells (p-MPSCs) without hole transport layers have garnered considerable interest because of their outstanding benefits in terms of stability and cost. However, the use of carbon electrodes instead of hole transport materials and noble metal electrodes leads to energy level mismatch, which limits the power conversion efficiency (PCE) of p-MPSCs. In this work, a molecular doping strategy is proposed employing cyclopentylmethanamine to passivate surface and subsurface crystal defects in perovskite layers while inducing an energy shift toward the p-type in the perovskite region within carbon electrodes.
View Article and Find Full Text PDFACS Appl Energy Mater
January 2025
Advanced Materials Research Group, Faculty of Engineering, University of Nottingham, Nottingham NG7 2RD, United Kingdom.
Magnesium hydride (MgH) is a promising material for solid-state hydrogen storage due to its high gravimetric hydrogen capacity as well as the abundance and low cost of magnesium. The material's limiting factor is the high dehydrogenation temperature (over 300 °C) and sluggish (de)hydrogenation kinetics when no catalyst is present, making it impractical for onboard applications. Catalysts and physical restructuring (e.
View Article and Find Full Text PDFUltrasonics
December 2024
NDT&E Laboratory, Dalian University of Technology, Dalian 116085, China. Electronic address:
Ultrasonic time-of-flight diffraction (TOFD) technique is applied to non-destructive testing in engineering, but the dead zone influences its applicable range. Alternative TOFD techniques adopt the indirect diffracted waves having long propagation times to decouple from the lateral wave and detect near-surface defects. It should be noted that the applicability of these diffracted waves varies with parameter conditions employed for detection, e.
View Article and Find Full Text PDFUltramicroscopy
March 2025
The State Key Lab of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310058, PR China; ZJU-Hangzhou Global Scientific and Technological Innovation Center, Zhejiang University, Hangzhou 311215, PR China. Electronic address:
Ultrasonic atomic force microscopy (UAFM) is a powerful nondestructive subsurface imaging tool that is widely used to inspect material defects and analyze biological cells. The contrast in UAFM images, which is crucial for subsurface imaging quality, is directly influenced by the contact force between the probe and material. This contact force affects the subsurface contrast by influencing the propagation of the stress field from the vibrating probe into the material.
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