Laser-Shock-DrivenIn SituEvolution of Atomic Defect and Piezoelectricity in Graphitic Carbon Nitride for the Ionization in Mass Spectrometry

Abstract

Nanostructures�coupled with mass spectrometry� have been intensively investigated to improve the detection sensitivity and reproducibility of small biomolecules in laser desorption/ionization mass spectrometry (LDI-MS). However, the impact of laser-induced shock wave on the ionization of the nanostructures has rarely been reported. Herein, we systematically elucidate the laser shock wave effect on the ionization in terms of the in situ development of atomic defects and piezoelectricity in two-dimensional graphitic carbon nitride nanosheets (g-C 3 N 4 NS) by short laser pulses. The mass analysis results of immunosuppressive drugs verify the enhanced LDI-MS performance, structurally originating from anisotropic lattice distortions in g-C 3 N 4 NS, i.e., in-plane extension (contraction) and out-ofplane contraction (extension) that modulate the charge carrier motion. Along with the experimental investigations, density functional theory calculations on Mulliken charges and dipole moments demonstrate the contribution of defect and piezoelectricity to the ionization. The results of this study provide a mechanistic understanding of the underlying ionization processes, which is crucial for revealing the full potential of laser shock waves in LDI-MS.

Multifunctional carbon nitride nanoarchitectures for catalysis

“…184 In a rather unique approach, laser irradiation was utilized to fabricate atomic defects in a CN structure, which resulted in piezoelectricity with strong structural distortion when the laser power was increased to more than 348.4 MW cm −2 . 185 Through the thermal polymerization route, using KOH, C 3 N x compounds were synthesized with a tunable band structure due to the N vacancies which led to enhanced separation in the photo-excited charge carriers. 186 Another strategy to introduce defects is through steam engineering for developing carbon vacancies in a CN polymer matrix which leads to improvement in CO 2 reduction efficiency.…”

Electrocatalytic hydrogenation coupling oxidation using water in a highly efficient paired cell enabled by an oxygen defect-rich layered double hydroxide

“…S25†), the electronegativity of the reactant intermediates in the NiFe- V o model is higher than that of NiFe, indicating that more charge accumulates and it is easier to be reduced. 60,61 It is obvious that the presence of V O promotes the charge transfer between the reactant intermediate and the active site, thus enhancing the interaction and promoting the reaction.…”

Role of Chalcogenides in Sensitive Therapeutic Drug Monitoring Using Laser Desorption and Ionization

“…Specifically, first-principles calculations using DFT enable the estimation of electronic interactions occurring at the atomic scale. − For example, Fukui functions can be used to identify the electrophilic and nucleophilic sites as well as to visualize the electrostatic potential (ESP) of molecular systems by providing information on charge distribution . In addition, the activation energies for chemical reactions such as protonation can be estimated, which can provide valuable chemical information to the studies of mass spectrometry. , …”