A novel aggregation- and crystallization-induced emission luminophore (ENPOMe) containing tetraphenylethene and acrylonitrile moieties with high fluorescence efficiency (Φ_F of up to 0.85) has been easily synthesized. ENPOMe has an exceptionally large two-photon absorption cross section (σ) of 5548 GM, and exhibits striking multi-stimuli-responsive single- and two-photon fluorescence switching with excellent reversibility in the solid state.

Upconversion photodynamic therapy (UC‐PDT), which integrates upconversion nanoparticles (UCNPs) with photosensitizers (PSs), presents a promising advancement in the field of phototherapy. However, despite the extensive studies focused on the design and synthesis of UCNPs, there is a paucity of systematic research on the mechanisms underlying the synergistic upconversion photodynamic effects. Here we have synthesized upconversion core@dotted‐shell nanoparticles (CDSNPs) and covalently tethered them with two distinct PSs, thereby constructing a dual‐PS UC‐PDT system with high synergistic photodynamic performance. To unravel the mechanism underlying the synergism, we employed a combination of quantum mechanical calculations and ultrafast time‐resolved spectroscopy techniques. The results indicate that rare earth oxides play a pivotal role in enhancing the intersystem crossing processes of PSs through modulating their excited electronic states. Additionally, Förster resonance energy transfer between two distinct PSs contributes to the amplification of triplet state populations, thus further enhancing the photodynamic effect. In vitro experiments demonstrate that the prepared CDSNPs based dual‐PS system exhibits excellent biocompatibility with normal cells and exceptional synergistic photodynamic efficacy against tumor cells upon near‐infrared excitation. This research contributes theoretical insights into the design and application of multi‐photosensitizer UC‐PDT systems, laying the groundwork for more efficient preclinical implementations in the future.

The photoluminescence spectra of $\mathrm{W}{\mathrm{O}}_{3-x}$ nanowire networks, $\mathrm{W}{\mathrm{O}}_3$ nanowires networks, and the bulk phase $\mathrm{W}{\mathrm{O}}_3$ powder have been investigated under the continuous wave excitation light at $320\mathrm{nm}$ . Two broad band emissions in spectrum of $\mathrm{W}{\mathrm{O}}_{3-x}$ nanowire networks are observed including the ultraviolet-visible (UV-vis) emission centered at $395\mathrm{nm}$ and the blue emission centered at $467\mathrm{nm}$ . The authors demonstrate that the blue emission in $\mathrm{W}{\mathrm{O}}_{3-x}$ nanowire networks is due to band-band transition of the bulk phase $\mathrm{W}{\mathrm{O}}_3$ and the UV-vis emission is attributed to the state of oxygen vacancies, which are characterized by using scanning electron microscopy and x-ray photoelectron spectroscopy. The UV-vis emission exhibits a strong dependence on the excitation wavelength, while the blue emission is independent of the excitation wavelength. The UV-vis emission is discussed in configuration-coordinate diagram of a localized state of oxygen vacancies. In particular, this state of defect is a high-lying resonant state in the conduction band of $\mathrm{W}{\mathrm{O}}_3$ .

We demonstrate that the colorizing effect of angle dependence can be efficiently and conveniently achieved on the rippled surface of pure copper processed by the femtosecond laser with an out-of-focus method, which greatly improves the machining speed. Such a laser-induced colorization can occur in a wide range of laser fluence, which determines the coverage and morphological characteristics of laser-induced ripples and thus can finely tune the colorizing effect. By inspecting the colors and corresponding spectra of treated areas at different angles, the relationship between the diffracted light central wavelength and the laser-induced near-subwavelength grating is analyzed quantitatively based on the fundamental grating equation with the experimental grating parameters. The spectrum analysis indicates that for the laser fluence increasing in a suitable range, the more clarity and regularity of formed ripples should bring out a more prominent grating effect, which becomes further matching of the grating equation in a larger inspecting angle for the elimination of the influence of the diffused reflection light. In short, the study confirms that the colorizing phenomenon mainly ascribes to the grating diffraction effect of the laser-induced periodic surface ripples, which would help to enable the flexible control of the colorizing effect induced by laser processing on pure copper.

Valley photonic crystal is a typical strategy of topological photonics with promising applications for novel integrated waveguides. The valley pseudospin provides an intrinsic paradigm to implement unidirectional coupling with robustly optical transport. But the key issue on the analysis of unidirectional coupling based on topological modes is lack of deep understanding on valley photonic crystals. In this work, we systematically study the mechanism and performance of unidirectional coupling between valley photonic crystal waveguides and chiral dipole emitters. Forming by two topologically-distinct valley photonic crystals, there are two types of valley-interface waveguides, i.e. bearded stack with glide-plane symmetry and zigzag stack with inversion symmetry. Analytical derivation shows that the Stokes parameters of topological eigenmodes can predict the directionality in the above two types of valley-interface waveguides, which is also confirmed by full-wave simulations. The strategy of bearded valley-interface waveguide can be easier to achieve high efficiency of unidirectional coupling than the zigzag case, and can relax the bias error of frequency and source location. It is also proved that the topological-protected unidirectional coupling supports robust transport against sharp-bending interface. Finally, we give a brief summary and perspective in the development of topological integrated photonics. This work gives a deterministic guidance on chiral light-matter interaction based on topological photonics, as well as shows the outlook of topological integrated photonics.