Pressure induced photoluminescence modulation in a wide range and synthesis of monodispersed ternary AgCuS nanocrystal based on Ag2S nanocrystals

An investigation of the effect of high-pressure on charge transfer in dye-sensitized solar cells based on surface-enhanced Raman spectroscopy

The interfacial charge transfer (CT) that plays an important role in enhancing the photoelectric conversion efficiency of dye-sensitized solar cells (DSSCs) has not always been fully explored. Here, a TiO₂@N719@Ag DSSC system was constructed, and the CT processes have been monitored by surface-enhanced Raman scattering (SERS) spectra. Meanwhile, it is well known that as one of the most common external stimuli, high pressure can increase the free carrier density of TiO₂ NPs and cause the band gap to narrow. In the high pressure SERS experiment, we observed a significant enhancement of the N719 dye in the TiO₂@N719@Ag system up to 2.48 GPa, which is consistent with the variation trend of the charge transfer degree (ρ_CT). It is indicated that band gap changes will strongly affect the CT processes, further influence the SERS signal intensity (or ρ_CT), and thus increase the CT probability of DSSCs. Furthermore, the decoration of Ag NPs in the TiO₂@N719@Ag DSSC system can introduce localized surface plasmon resonance (LSPR), enhance the light trapping ability and offer additional CT pathways. Importantly, it is possible to improve the photoelectric conversion performance of DSSCs via the high pressure method and the introduction of Ag NPs. Finally, in order to observe the CT process of DSSCs more clearly, the models describing the CT mechanism have been proposed. SERS spectroscopy is expected to be a promising technique for the exploration of the interfacial CT behavior in DSSC devices, which may further broaden the thoughts of improvement of efficiency of the cells.

Perspectives for Ag2S NIR-II nanoparticles in biomedicine: from imaging to multifunctionality

Research on near-infrared (NIR) bioimaging has progressed very quickly in the past few years, as fluorescence imaging is reaching a credible implementation as a preclinical technique. The applications of NIR bioimaging in theranostics have contributed to its increasing impact. This has brought about the development of novel technologies and, simultaneously, of new contrast agents capable of acting as efficient NIR optical probes. Among these probes, Ag₂S nanoparticles (NPs) have attracted increasing attention due to their temperature-sensitive NIR-II emission, which can be exploited for deep-tissue imaging and thermometry, and their heat delivery capabilities. This multifunctionality makes Ag₂S NPs ideal candidates for theranostics. This review presents a critical analysis of the synthesis routes, properties and optical features of Ag₂S NPs. We also discuss the latest and most remarkable achievements enabled by these NPs in preclinical imaging and theranostics, together with a critical assessment of their potential to face forthcoming challenges in biomedicine.

Structural evolution induced by Au atom diffusion in Ag2S

The transition from amorphous Ag₂S to crystalline AuAgS or Ag₃AuS₂ was discovered through Au single-atom diffusion.