Fig. 4: Electromagnetic field-related enhancement of photo upconversion and CPL.
a–d TEM images of a AuNR653, b AuNR@Ag659, c AuNR737, and d AuNR812. Scale bar = 200 nm. e Normalized extinction spectra of AuNR737 (cyan), AuNR812 (blue), and AuNR@Ag659 (red). The black dashed line indicates the excitation at 635 nm. f Upconverted photoluminescence spectra of R−1UCM and R-1UCM couples with different plasmonic nanorods in deaerated water under excitation of 635 nm laser. [R-1] = 5 × 10−5 mol L−1, [PdTPBP] = 10−5 mol L−1, [CTAB] = 10−2 mol L−1, molar ratio AuNR653/R−1 = 4.2 × 10−6/1, 4.2 × 10−6/1, 3.0 × 10−6/1, and 2.6 × 10−6/1 for AuNR812, AuNR737, AuNR653, and AuNR@Ag659, respectively. A 635 nm short-pass filter was set in front of the detector to remove the scattering incident light. g Calculated electric field enhancement contours at 635 nm for different nanorods. Scale bar = 10 nm. h Plots of glum versus gCD. All error bars show mean ± standard deviation. n = 3 independent experiments. i Energy-level diagram for the plasmon-assisted UC-CPL process of R−1/PdTPBP fluorophore pair. The black spiral lines represent the chirality-induced spin polarization in the process of TTET and TTA. Source data are provided as a Source Data file.
