Self-assembled monolayers (SAMs) that contain fluorophore units are nowadays widely used to tune surface properties and design new chemical sensor chips. It is well-known that the nature of the substrate may strongly interfere with the emission properties of the grafted molecules, but the organization of the monolayer may also have an important role. To study the influence of the SAM organization on the luminescence properties, we prepared different coumarin-based derivatives endowed with tethered chains of different lengths and elaborated the corresponding SAMs on glass slides. Besides SAM structural characterizations by atomic force microscopy and X-ray reflectivity, we carried out contact angle measurements and applied the Van Oss-Chaudhury-Good theory, which was rarely used previously for self-assembled monolayers. As expected, by increasing the tethered chain length, a higher surface coverage, a higher degree of organization, and a stronger molecular packing were observed. However, it appears to facilitate the self-quenching process, and thus, this strongly affects the fluorescent properties of the SAMs.
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http://dx.doi.org/10.1021/la401536p | DOI Listing |
Int J Mol Sci
December 2024
Department of Chemistry, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 04763, Republic of Korea.
The effect of solution pH on the formation and surface structure of 2-pyrazinethiolate (2-PyzS) self-assembled monolayers (SAMs) formed by the adsorption of 2-mercaptopyrazine (2-PyzSH) on Au(111) was investigated using scanning tunneling microscopy (STM) and X-ray photoelectron microscopy (XPS). Molecular-scale STM observations clearly revealed that 2-PyzS SAMs at pH 2 had a short-range ordered phase of (2√3 × √21)R30° structure with a standing-up adsorption structure. However, 2-PyzS SAMs at pH 8 had a very unique long-range ordered phase, showing a "ladder-like molecular arrangement" with bright repeating rows.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Key Laboratory of Green Printing, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
Self-assembled monolayers (SAM) as hole transport layers have been widely used in high-efficiency inverted perovskite solar cells (PSCs) exceeded 26 %. However, the poor coverage and non-uniform distribution on the substrate of SAM further restrict the improvement of device performance. Herein, we utilize the mixed SAM strategy via the MeO-2PACz along with perfluorotripropylamine (FC-3283) to improve the SAM coverage, aiming to accelerate the carrier transport, promote the perovskite growth, regulate the surface energy levels and suppress the nonradiative recombination.
View Article and Find Full Text PDFBiosens Bioelectron
December 2024
Department of Physical Chemistry, Institute of Chemistry, Faculty of Chemistry and Geosciences, Vilnius University (VU), Naugarduko St. 24, LT-03225, Vilnius, Lithuania; Department of Nanotechnology, State Research Institute Center for Physical and Technological Sciences (FTMC), Sauletekio Ave. 3, LT-10257, Vilnius, Lithuania. Electronic address:
Herein, we report the development and characterisation of an electrochemical biosensor with a polypyrrole (Ppy)-based molecularly imprinted polymer (MIP) for the serological detection of the recombinant nucleocapsid protein of SARS-CoV-2 (rN). The electrochemical biosensor utilises a Ppy-based MIP formed on a self-assembled monolayer (SAM) at the gold interface to enhance Ppy layer stability on the screen-printed electrode (SPE). Electrochemical impedance spectroscopy (EIS) and square wave voltammetry (SWV) were employed for the electrochemical characterisation of screen-printed gold electrodes (SPGEs) modified with MIP or non-imprinted polymer (NIP) layers.
View Article and Find Full Text PDFNanoscale
January 2025
Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen 518055, China.
The highly anisotropic and nonadditive nature of nanoparticle surfaces restricts their characterization by limited types of techniques that can reach atomic or molecular resolution. While small-angle neutron scattering (SANS) is a unique tool for analyzing complex systems, it has been traditionally considered a low-resolution method due to its limited scattering vector range and wide wavelength spread. In this article, we present a novel perspective on SANS by showcasing its exceptional capability to provide molecular-level insights into nanoparticle interfaces.
View Article and Find Full Text PDFACS Appl Mater Interfaces
January 2025
School of Materials Science and Engineering, Kyungpook National University, Daegu 41566, Republic of Korea.
The development of quantum dot light-emitting diodes (QLEDs) represents a promising advancement in next-generation display technology. However, there are challenges, especially in achieving efficient hole injection, maintaining charge balance, and replacing low-stability organic materials such as PEDOT:PSS. To address these issues, in this study, self-assembled monolayers (SAMs) were employed to modify the surface properties of NiO, a hole injection material, within the structure of ITO/HIL/TFB/QDs/ZnMgO/Al QLEDs.
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