We present a three-dimensional patterned (3DP) multifunctional substrate with the functions of ultra-thin layer chromatography (UTLC) and surface enhanced Raman scattering (SERS), which simultaneously enables mixture separation, target localization and label-free detection. This multifunctional substrate is comprised of a 3DP silicon nanowires array (3DP-SiNWA), decorated with silver nano-dendrites (AgNDs) atop. The 3DP-SiNWA is fabricated by a facile photolithographic process and low-cost metal assisted chemical etching (MaCE) process. Then, the AgNDs are decorated onto 3DP-SiNWA by a wet chemical reduction process, obtaining 3DP-AgNDs@SiNWA multifunctional substrates. With various patterns designed on the substrates, the signal intensity could be maximized by the excellent confinement and concentrated effects of patterns. By using this 3DP-AgNDs@SiNWA substrate to scrutinize the mixture of two visible dyes, the individual target could be recognized and further boosted the Raman signal of target 15.42 times comparing to the un-patterned AgNDs@SiNWA substrate. Therefore, such a three-dimensional patterned multifunctional substrate empowers rapid mixture screening, and can be readily employed in practical applications for biochemical assays, food safety and other fields.

We present a multifunctional substrate of ultrathin‐layer chromatography (UTLC) and surface‐enhanced Raman scattering (SERS), which enables analytes separation and label‐free detection simultaneously. This integrated substrate is composed of silicon nanowires array (SiNWA), decorated with silver nano‐dendrites (AgNDs). This SiNWA is fabricated by a facile and low‐cost metal‐assisted chemical etching process, and the AgNDs are then decorated onto SiNWA by chemical reduction process. These AgNDs provide abundant hot spots by inducing strong localized electric field, which is confirmed by finite‐difference time‐domain simulation calculations. With the optimized multifunctional substrate, the screening of melamine is successfully validated. The high linear dependence of signal intensity and melamine concentrations from 15 to 1,500 ppm with small deviation was carried out by our developed UTLC–SERS substrate, providing a great potential for quantitative detection. Besides, the SERS signals further show a low relative standard deviation of 8.7%, benefited from the calibration by a peak located at 520 cm−1 of silicon. In short, such a low‐cost, high‐stable multifunctional substrate of UTLC and SERS can be readily employed for practical applications of rapid biochemical mixture screening.

We present a facile and cost-effective manner to fabricate a highly sensitive and stable surface enhanced Raman scattering (SERS) substrate. First, a silicon nanowire array (SiNWA) is tailored by metal-assisted chemical etching (MaCE) method as a scaffold of the desired SERS substrate. Next, with an oblique angle deposition (OAD) method, optimized gold nanoparticles (AuNPs) are successfully decorated on the surface of the SiNWA. These AuNPs enable a strong localized electric field, providing abundant hot spots to intensify the Raman signals from the targeting molecules. By applying a well-established methodology, Taguchi method, which is invented for designing experiments, the optimized combination of parameters is obtained efficiently. The experimental results are also confirmed by finite-difference time-domain (FDTD) simulation calculations. Besides, a gold metal backplate (AuMBP) is applied to further enhancing the Raman signal intensity. Based on this developed SERS substrate, we demonstrated an enhancement factor (EF) of 1.78 × 106 and a coefficient of variation (CV) of 4.2%. Both EF and CV indicate a highly stable property and the optimized SERS substrate substantially outperform the commercial product. In the end, we also demonstrate a quantitative measurement on practical application of detecting malachite green (MG) with concentration from 10 nM to 100 μM.

Researchers have focused on the development of Si nano- or micro-structured solar cells (SCs) because of their enhanced optical absorption properties and their ability to decouple minority carrier diffusion and light absorption paths. We adopt a low-cost method to monolithically fabricate Si-micrograting SC (SiMG-SC) with vertical sidewall electrodes and a vertical multi-junction, which minimizes the reflection losses from conventional planar metallic electrodes and increases the minority carrier collection probability. We consequently intensified the photovoltaic properties, i.e., the current density, fill factor, and power conversion efficiency, by 11.2%, 23.7%, and 52.9%, respectively, compared to those of the control SCs.