We report a dual-mode organic photodetector (OPD) that has a trilayer visible light absorber/optical spacer/near-infrared (NIR) light absorber configuration. In the presence of NIR light, photocurrent is produced in the NIR light–absorbing layer due to the trap-assisted charge injection at the organic/cathode interface at a reverse bias. In the presence of visible light, photocurrent is produced in the visible light–absorbing layer, enabled by the trap-assisted charge injection at the anode/organic interface at a forward bias. A high responsivity of >10 A/W is obtained in both short and long wavelengths. The dual-mode OPD exhibits an NIR light response operated at a reverse bias and a visible light response operated at a forward bias, with a high specific detectivity of ~10¹³ Jones in both NIR and visible light ranges. A bias-switchable spectral response OPD offers an attractive option for applications in environmental pollution detection, bioimaging process, wellness, and security monitoring in two distinct bands.

Cerium metal–organic framework based composites (Ce-MOF/GO and Ce-MOF/CNT) were synthesized by a wet chemical route and characterized with different techniques to characterize their crystal nature, morphology, functional groups, and porosity. The obtained Ce-MOF in the composites exhibit a nanorod structure with a size of ∼150 nm. The electrochemical performance of the composites was investigated in 3 M KOH and 3 M KOH + 0.2 M K₃Fe(CN)₆ electrolytes. Enhanced electrochemical behavior was obtained for the Ce-MOF/GO composite in both electrolytes and exhibited a maximum specific capacitance of 2221.2 F g⁻¹ with an energy density of 111.05 W h kg⁻¹ at a current density of 1 A g⁻¹. The large mesoporous structure and the presence of oxygen functional groups in Ce-MOF/GO could facilitate ion transport in the electrode/electrolyte interface, and the results suggested that the Ce-MOF/GO composite could be used as a high-performance supercapacitor electrode material.

Active metasurfaces are emerging as the core of next-generation optical devices with their tunable optical responses and flat-compact topography. Especially for the terahertz band, active metasurfaces have been developed as fascinating devices for optical chopping and compressive sensing imaging. However, performance regulation by changing the dielectric parameters of the integrated functional materials exhibits severe limitations and parasitic losses. Here, we introduce a C-shape-split-ring-based phase discontinuity metasurface with liquid crystal elastomer as the substrate for infrared modulation of terahertz wavefront. Line-focused infrared light is applied to manipulate the deflection of the liquid crystal elastomer substrate, enabling controllable and broadband wavefront steering with a maximum output angle change of 22° at 0.68 THz. Heating as another control method is also investigated and compared with infrared control. We further demonstrate the performance of liquid crystal elastomer metasurface as a beam steerer, frequency modulator, and tunable beam splitter, which are highly desired in terahertz wireless communication and imaging systems. The proposed scheme demonstrates the promising prospects of mechanically deformable metasurfaces, thereby paving the path for the development of reconfigurable metasurfaces.

Transparent wood with high optical transmittance, excellent thermal insulation and high toughness has attracted significant attention as an energy-saving building material. Many research efforts were dedicated to functional transparent wood, from luminescent to electrochromic transparent wood. However, photochromic transparent wood that is highly desirable and critical for smart window applications has been rarely studied. Herein, we experimentally demonstrate photochromic transparent wood with photo-switching of transmittance in the visible light region and color tuning properties. The photochromic transparent wood was obtained by infiltrating the lignin modified wood template with a mixture of photochromic material 3′,3′-dimethyl-6-nitro-spiro[2H-1-benzopyran-2,2′-indoline]-1′-ethanol (DNSE) and pre-polymerized methyl methacrylate (MMA). This photochromic transparent wood exhibits a vibrant purple-to-colorless color change under the illumination of light. In addition, dichroic dye material doped photochromic woods were studied for providing more color change choices. The proposed photochromic transparent wood shows potential applications in mechanically robust, energy-efficient, photo-switchable, and colorful smart windows on a large scale.