The physicochemical properties of nanostructured substrates significantly impact laser desorption/ionization mass spectrometry (LDI-MS) performance. Fundamental understanding of the substrate properties can provide insights into the design and development of an efficient LDI matrix. Herein, a hybrid matrix of nanoporous Au-modified TiO2 nanowires (npAu-TNW) is developed to achieve enhanced LDI-MS performance. Its origin is investigated based on hybrid matrix properties including photo–thermal conversion and electronic band structure. Notably, further improvement is obtained in the npAu-TNW than in the pristine TNW and non-porous Au nanoisland-modified TNW (Au-TNW) hybrid, which is attributed to the laser-induced surface restructuring/melting phenomenon. Noticeable surface restructuring/melting occurs in the npAu by laser exposure through efficient photo–thermal conversion of the highly porous npAu. At this instant of npAu structural changes, internal energy transfer from the npAu to the adsorbed analyte is promoted, which facilitates desorption. Moreover, strain is developed in situ in the TNW adjacent to the restructuring npAu, which distorts the TNW lattice. The strain development reduces recombination rates of charge carriers by introducing shallow trap levels in the bandgap, which enhances the ionization process. Ultimately, the high LDI-MS performance based on the npAu-TNW hybrid matrix is demonstrated by analyzing neurotransmitter.
Bibliographical noteFunding Information:
This work was supported by the National Research Foundation of Korea (grant numbers: NRF‐2020R1A2B5B01002187 and NRF‐2020R1A5A101913111).
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All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics