Developing well-defined nanostructures with superior surface-enhanced Raman scattering (SERS) performance is a critical and highly desirable goal for the practical applications of SERS in sensing and analysis. Here, a SERS-active substrate was fabricated by decorating a MoS₂ monolayer with Ag nanowire (NW) and nanoparticle (NP) structures, using a spin-coating method. Both experimental and theoretical results indicate that strong SERS signals of rhodamine 6G (R6G) molecules can be achieved at “hotspots” formed in the Ag NW-Ag NP-MoS₂ hybrid structure, with an enhancement factor of 10⁶. The SERS enhancement is found to be strongly polarization dependent. The fabricated SERS substrate also exhibits ultrasensitive detection capabilities with a detection limit of 10^–11 M, as well as reliable reproducibility and good stability.

The capability to detect light over a broad waveband is highly important for practical optoelectronic applications and has been achieved with photodetectors of one-dimensional inorganic nanomaterials such as Si, ZnO, and GaN. However, achieving high speed responsivity over an entire waveband within such a photodetector remains a challenge. Here we demonstrate a broadband photodetector using a single polyaniline nanowire doped with quantum dots that is highly responsive over a broadband from 350 to 700 nm. The high responsivity is due to the high density of trapping states at the enormous interfaces between polyaniline and quantum dots. The interface trapping can effectively reduce the recombination rate and enhance the efficiency for light detection. Furthermore, a tunable spectral range can be achieved by size-based spectral tuning of quantum dots. The use of organic–inorganic hybrid polyaniline nanowires in broadband photodetection may offer novel functionalities in optoelectronic devices and circuits.

Developing a universal and simple structure with an excellent fluorescence enhancement is a highly desirable goal for practical applications in optical detection and imaging.