Traditional colloid SERS substrates are mostly based on metal nanoparticles (MNPs), which have complex and time-consuming fabrication processes, poor structural control, and are susceptible to oxidation. As a result, solid-state SERS substrates have emerged as an effective alternative. Here, we propose using two-step mild and hard anodization to fabricate ordered anodic aluminum oxide (AAO) substrates with high total pore circumference for SERS detection. Hybrid pulse anodization (HPA) enables the fabrication of AAO at room temperature using 40 V in the first step and 40, 110, and 120 V in the second step of anodization. The different voltages applied in the second step effectively control the pore diameter, thereby achieving various nanostructures. The enhancement mechanism primarily originates from the high total pore circumference of nanostructures, which generates abundant hot spots around the pore peripherals, thereby significantly amplifying the SERS signal. Sorbic acid is a common preservative widely used in food products and employed as a test substance on high regularity AAO substrates at concentrations of 1000 ppm to 10 ppb. The resulting SERS spectra exhibited distinct characteristic peaks at 1640–1645 cm⁻¹. The analytical enhancement factor is calculated as 1.02 × 10⁵ at the AAO substrate prepared by 110 V with the Si substrate as the reference. By appropriately tuning the process parameters, a limit of detection (LOD) as low as 10 ppb of sorbic acid was achieved.

Triboelectric nanogenerators (TENG) show significant potential in pressure sensing by converting mechanical disturbances into electrical signals positively correlated with the magnitude of the applied force, yet their development as practical pressure sensors is severely hindered by the major drawback of only detecting transient mechanical inputs. Additionally, traditional dual-mode pressure sensors have typically required complex multilayer structures and time-consuming fabrication processes. Here, a simple dual-mode pressure sensor of novel structure integrated with TENG and anodic aluminum oxide (AAO) for both dynamic and static pressure detection is proposed. Nanoporous AAO is directly grown on an aluminum substrate to simplify the traditionally complex multi-layer structure of dual-mode pressure sensors. The AAO layer serves a dual functionality by acting as an active triboelectric layer that significantly enhances the triboelectric output performance while concurrently functioning as the capacitive dielectric layer. A polydimethylsiloxane (PDMS) film is employed as the elastic counterpart to pair with the AAO substrate. The influence of PDMS thickness on the charge accumulation and extraction of the TENG mode is investigated to optimize the device output. Under optimal configurations, the streamlined Al-AAO/PDMS sensor demonstrates good sensitivity and linearity (R² > 0.99) for both dynamic triboelectric voltage (1.05 V/kPa) and static capacitance (5.56 pF/kPa) over a wide sensing range of 1–73 kPa. This dual-mode sensor effectively overcomes the transient limitation of conventional single-mode TENGs and shows significant potential for future smart tactile applications.