A flexible and transparent triboelectric nanogenerator (FT-TENG) has great potential for application in self-powered biosensor systems, electronic skin and wearable electronic devices. However, improving the output performance with little damage to its optical properties is challenging. Herein, we have developed an FT-TENG that has a well-ordered nest-like porous polydimethylsiloxane (NP-PDMS) film and graphene transparent electrodes. The NP-PDMS film with ordered pores is fabricated by hydrochloric acid etching of 500 nm sized ZnO spheres made of aggregated nanoparticles, having a light transmittance of 81.8% and a water contact angle of 118.62°. The FT-TENG based on the NP-PDMS film with a porosity of 12%, gives a maximum output of 271 V and 7.8 μA, which are respectively, 3.7 and 2.1-fold of those of a TENG with a flat PDMS film. The peak output power reaches 0.39 mW with a load resistance of 9.01 MΩ. The dielectric constant and effective thickness of the NP-PDMS film and the capacitance and charge transfer of the FT-TENG are systematically investigated. This work provides a novel and effective method to enhance the performance of FT-TENGs with little damage to their optical properties.

Blazed gratings are the critical dispersion elements in spectral analysis instruments, whose performance depends on structural parameters and topography of the grating groove. In this paper, high diffraction efficiency silicon-blazed grating working at 800–2500 nm has been designed and fabricated. By diffraction theory analysis and simulation optimization based on the accurate boundary integral equation method, the blaze angle and grating constant are determined to be 8.8° and 4 μm, respectively. The diffraction efficiency is greater than 33.23% in the spectral range of 800–2500 nm and reach the maximum value of 85.62% at the blaze wavelength of 1180 nm. The effect of platform and fillet on diffraction efficiency is analyzed, and the formation rule and elimination method of the platform are studied. The blazed gratings are fabricated by anisotropic wet etching process using tilted (111) silicon substrate. The platform is minished by controlling etching time and oxidation sharpening process. The fillet radius of the fabricated grating is 50 nm, the blaze angle is 7.4°, and the surface roughness is 0.477 nm. Finally, the blazed grating is integrated in scanning micromirror to form scanning grating micromirror by MEMS fabrication technology, which can realize both optical splitting and scanning. The testing results show that the scanning grating micromirror has high diffraction efficiency in the spectral range of 810–2500 nm for the potential near-infrared spectrometer application.

2D-piezoelectric materials are attractive for micro-electromechanical systems (MEMS), medical implants and wearable devices because of their numerous exceptional properties. 2D-hybrid organic–inorganic perovskites (HOIPs) have attracted extensive research interest due to their merits of structural diversity, good mechanical flexibility, and ease of fabrication. The electronic energy band, charge density and the elastic properties of 2D-HOIP-[C₆H₁₁NH₃]₂MX₄ (M = Ge, Sn, Pb; X = Cl, Br, I) were investigated using first-principles calculations. The excellent piezoelectricity of 2D-HOIP-[C₆H₁₁NH₃]₂MX₄ has been analyzed in detail. More importantly, 2D-[C₆H₁₁NH₃]₂MX₄ have giant intrinsic positive and negative out-of-plane piezoelectric coefficients under the effect of van der Waals interaction. The d₃₁ and d₃₂ of [C₆H₁₁NH₃]₂SnBr₄ are 82.720 pm V⁻¹ and −36.139 pm V⁻¹, respectively, which are among the largest piezoelectric coefficients among all kinds of atomic-thick 2D materials reported. The high flexibility together with the giant out-of-plane piezoelectricity would endow these 2D-HOIP-[C₆H₁₁NH₃]₂MX₄ with potential applications in ultrathin piezoelectric cantilever and diaphragm devices.

Recently, organic-inorganic hybrid perovskite has attracted increasingly attention because of its excellent piezoelectric and ferroelectric properties. In this paper, the first principles method was employed to analyze the piezoelectric properties of two-dimensional (2D) organic-inorganic perovskite (4-aminotetrahydropyran, ATHP) ₂ PbX ₄ (X = Cl, Br and I). The calculation shows that 2D (ATHP) ₂ PbX ₄ has large out-of-plane dipole moment and excellent out-of-plane piezoelectric properties. Among them, the out-of-plane piezoelectric coefficient d₃₁ of 2D (ATHP) ₂ PbI ₄ reaches 41.90 pm/V, which is about 8 times the out-of-plane piezoelectric coefficient d₃₃ of bulk material AlN, and one to two orders of magnitude larger than d₃₁ of most 2D piezoelectric materials. The electronic properties of 2D (ATHP) ₂ PbX ₄ are calculated to reveal its energy band structure and charge density. The elastic tensors of 2D (ATHP) ₂ PbX ₄ is calculated. The stress-strain analysis suggested the 2D (ATHP) ₂ PbX ₄ has an ultra-soft mechanical flexibility. Our research shows that 2D (ATHP) ₂ PbX ₄ is of great application value in various micro-nano piezoelectric devices.

Accurate gas detection is essential for mitigating harmful gas emissions and ensuring production safety. This study introduces an FR4-based tunable Fabry-Pérot (F-P) filter equipped with an electromagnetic actuator to address the precision limitations of conventional gas detectors. Simulations and analyses were performed on distributed Bragg reflectors with various multilayer film configurations on silicon and silicon dioxide substrates. Results indicate that a five-layer (poly-Si/SiO ₂ ) membrane stack reflector achieves a high reflectance of 98.51%, enabling the filter to attain a Full Width at Half Maximum ( FWHM ) of 0.9 nm and a free spectral range ( FSR ) of 173.6 nm. To overcome the challenges of limited cavity length control in the F-P cavity, a novel electromagnetically actuated cascaded folded beam structure, designed via finite element analysis, is proposed. This mechanism achieves a reflector displacement of 1.6 μm under a low actuating voltage of 30 mV while maintaining a parallelism finesse exceeding 300. Additionally, the system achieves a displacement tuning precision of 22.7 nm/mA, surpassing existing designs, and the displacement adjustment error below 20 nm. Experimental validation demonstrated an excellent linear correlation (R²=0.9998) between the applied signals and reflector displacements, facilitating precise wavelength control. The proposed methane detection system, based on the electromagnetic F-P tunable filter, exhibits significant potential for high-precision methane monitoring in environmental and industrial applications.

Micro-gratings have become pivotal components in advanced optical systems, offering precise light manipulation and analysis. However, achieving a high spectral resolution and enlarged scanning angles without sacrificing linearity remains a challenging endeavor. This paper presents an electromagnetically driven micro-grating designed to address these challenges. To achieve these enhancements, our work employs a multi-degree-of-freedom resonator design which comprises a grating, an actuator coil frame, an integrated angle sensor, and four cantilever torsion springs. The scanning angle amplification effect is realized through optimizing the MIMO (Multiple-Input-Multiple-Output) behavior associated with the system’s second-order harmonic. With the amplification effect of scanning angle, a minor displacement in the actuator coil frame can achieve a significant scanning angle on the grating. A theoretical model of proposed multi-degree-of-freedom design has been established together with a finite element simulation model. The potential optimization parameters have been analyzed and discussed in detail. We fabricated a demonstrator based on Flame-Retardant-4 material, and the experiment results showed the device with mirror size 12mm × 12mm could reach a 6.94° scanning angle with a 75 mArms drive current. The amplification ratio of 1.84 (drive coil 3.77°) could be observed aligning well with harmonic simulation’s prediction. Also, The micro-grating exhibits excellent linearity with a correlation coefficient of 0.99979.