The performance of chemical reactions has been enhanced immensely with surface plasmon resonance (SPR)-based sensors. In this review, the principle and application of SPR sensors are introduced and summarized thoroughly. We introduce the mechanism of the SPR sensors and present a thorough summary about the optical design, including the substrate and excitation modes of the surface plasmons. Additionally, the applications based on SPR sensors are described by the Raman and fluorescence spectroscopy in plasmon-driven surface catalytic reactions and the measurement of refractive index sensing, especially.
Raman spectroscopy can be used as a rapid diagnosis tool in lung cancer to help us understand cancer progression at molecular level and improve clinical practices.
The band-edge carrier recombination rate determines the internal quantum efficiency of light-emitting diodes (LEDs), which is predominantly determined by the carrier lifetime. Point defects in transition metal dichalcogenides (TMDs) as dominant nonradiative recombinations affect the carrier lifetimes, hindering photon emission. Uncovering the mechanism of different defect types on carrier lifetimes in TMDs is still controversial and challenging. Here, we combine time-resolved photoluminescence measurement with nonadiabatic molecular dynamics calculation to explore the bandedge carrier lifetime in monolayer WS 2 with three typical kinds of defects. We have found that vacancy defects and compensatory doping defects in TMDs lead to decreased bandedge carrier lifetimes by 2 or 1 order of magnitude compared with pristine WS 2 , respectively. We attribute the difference to the phonon modes involved in electron− phonon coupling caused by defect types. Such an insight into the carrier lifetime can help modulate the defects in TMDs, so as to improve the performance of LEDs in the future.
In this paper, photoinduced intermolecular charge transfer (PICT) and fluorescence resonance energy transfer (FRET) in donor-acceptor systems have been investigated experimentally and theoretically. We attempt to investigate the natural relationship between FRET and PICT, and reveal the advantages of FRET enhanced PICT. The driving force for PICT in the FRET system equals the reorganization energy, which gives barrier-less charge transfer according to Marcus theory. The rates of PICT in the FRET system can be estimated with our simplified Marcus equation. Our results can promote the deeper understanding of the nature of FRET enhanced PICT, and benefit rational design for the use of the FRET system in organic solar cells.
We experimentally report a new photoisomerization mechanism of fluorescence resonance energy transfer (FRET) of monomer via photoisomerization. Firstly, a new photoisomerization was firstly report by us, in which trans, trans-1,4-Diphenyl-1,3-butadiene (tt-DPB) is photoisomerized to D-DPB (D stands for rotating double bond) by rotating double bond, evidenced by the three dimensional (3D) and 2D excitationemission mappings, and firmly supported by theoretical calculations on potential energy surfaces. Secondly, absorption energy of the photoisomerized D-DPB is resonated with the fluorescence energy of tt-DPB. By the electronic state excitation of tt-DPB, the fluorescence of D-DPB is observed, which provide evidence of the FRET of DPB via photoisomerization. Our results provide a new mechanism on FRET of monomer via photoisomerization.
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