ABSTRACT
Herein, a simply-prepared and highly sensitive electric field-induced surface-enhanced Raman spectroscopy (E-SERS) substrate is proposed by combining a pyroelectric material (PMN-PT) with the plasmonic silver nanoparticles (Ag NP). The intensity of SERS signals is further enhanced by more than 100 times after the application of positive or negative pyroelectric potentials. Theoretical calculations and experimental characterizations demonstrate that the chemical mechanism (CM) as induced by the charge transfer (CT) is mainly responsible for enhanced E-SERS. In addition, a novel nanocavity structure with PMN-PT/Ag/Al2O3/silver nanocubes (Ag NCs) was also introduced, which could effectively convert light energy into heat energy and realize a tremendous enhancement of SERS signals. These findings are expected to further accelerate the application of plasmonic metal nanoparticle-based pyroelectric materials in the fields of energy conversion, optical-sensors and photocatalysts.
ABSTRACT
The relatively weak Raman enhanced factors of semiconductor-based substrate limit its further application in surface-enhanced Raman scattering (SERS). Here, a kind of two-dimensional (2D) semimetal material, molybdenum carbide (Mo2C) film, is prepared via a chemical vapor deposition (CVD) method, and the origin of SERS is investigated for the first time. The detection limits of the prepared Mo2C films for crystal violet (CV) and rhodamine 6G (R6G) molecules are low at 10-6 M and 10-8 M, respectively. Our detailed theoretical analysis, based on density functional theory and the finite element method, demonstrates that the enhancement of the 2D Mo2C film is indeed CM in nature rather than the EM effects. Besides, the basic doping strategies are proposed to further optimize the SERS sensitivity of Mo2C for Fermi level regulation. We believe this work will provide a helpful guide for developing a highly sensitive semimetal SERS substrate.
ABSTRACT
mHealth is one of China's national strategies that brings affordable, accessible, and convenient health care to its entire population, may they be in cities or rural areas. Although Chinese young adults are among the first to adopt mHealth, the factors influencing Chinese young adults to use mHealth are yet to be studied both empirically and in depth. This study explores the mechanism that determines Chinese young adults' intention to use mHealth, based on an extended Technology Acceptance Model (TAM). The extended TAM was tested using responses from 486 Chinese young adults. The results showed that perceived usefulness strongly and significantly influenced people's intention to use mHealth. Additionally, communication effectiveness, health consciousness, and perceived ease of use were found as significant factors influencing people's intention to use mHealth through perceived usefulness. Distrust was not found to significantly influence people's intention to use mHealth.
