We report an improved synthesis of colloidal gold nanorods (NRs) by using aromatic additives that reduce the concentration of hexadecyltrimethylammonium bromide surfactant to ~0.05 M as opposed to 0.1 M in well-established protocols. The method optimizes the synthesis for each of the 11 additives studied, allowing a rich array of monodisperse gold NRs with longitudinal surface plasmon resonance tunable from 627 to 1246 nm to be generated. The gold NRs form large-area ordered assemblies upon slow evaporation of NR solution, exhibiting liquid crystalline ordering and several distinct local packing motifs that are dependent upon the NR's aspect ratio. Tailored synthesis of gold NRs with simultaneous improvements in monodispersity and dimensional tunability through rational introduction of additives will not only help to better understand the mechanism of seed-mediated growth of gold NRs but also advance the research on plasmonic metamaterials incorporating anisotropic metal nanostructures.

Monodisperse 3.1 nm Ag2Te NCs show a sharp optical absorption feature at 1154 nm with a large linear temperature dependence and the photoconductive response consistent with semiconducting character in Ag2Te NCs. The wavelength of the resonance is within the window of transparency for biological tissue making it a potential in vivo temperature marker or transducer for in situ heating with deep-penetrating near-infrared radiation.

Bismuth ferrite (BiFeO3) has recently become interesting as a room‐temperature multiferroic material, and a variety of prototype devices have been designed based on its thin films. A low‐cost and simple processing technique for large‐area and high‐quality BiFeO3 thin films that is compatible with current semiconductor technologies is therefore urgently needed. Development of BiFeO3 thin films is summarized with a specific focus on the chemical solution route. By a systematic analysis of the recent progress in chemical‐route‐derived BiFeO3 thin films, the challenges of these films are highlighted. An all‐solution chemical‐solution deposition (AS‐CSD) for BiFeO3 thin films with different orientation epitaxial on various oxide bottom electrodes is introduced and a comprehensive study of the growth, structure, and ferroelectric properties of these films is provided. A facile low‐cost route to prepare large‐area high‐quality epitaxial BFO thin films with a comprehensive understanding of the film thickness, stoichiometry, crystal orientation, ferroelectric properties, and bottom electrode effects on evolutions of microstructures is provided. This work paves the way for the fabrication of devices based on BiFeO3 thin films.

Photonic and optoelectronic devices have been limited in most two-dimensional (2D) materials. Researchers have attempted diverse device structures, such as introducing some ferroelectric materials to form new hybrid materials that could improve the performance of these 2D devices. Ferroelectrics might adjust the carrier concentration, mobility, and bandgap of 2D materials to achieve non-volatile control of the photonic and optoelectronic properties. On the other hand, ferroelectrics have a spontaneous electric polarization that occurs below the Curie temperature and reverses under an applied electric field. The polarization can be modulated via incident light, while the light wavelengths can be tuned through switching the electric polarization. This could improve the performance of 2D photonic and optoelectronic devices. We believe that 2D materials, as an emerging member of 2D/ferroelectric hybrid materials, will have great potential in photonics and optoelectronics thanks to their tunable bandgap. Here, we provide a perspective of ferroelectrics on 2D materials for photonics and optoelectronics. We discuss the concept of ferroelectrics and their fundamentals and then present their unique advantages in optoelectronic devices.

Thin film ferroelectric capacitors (TFFCs) with excellent energy storage have attracted increasing attention due to the electronic devices toward miniaturization and integration. BiFeO3 (BF)/Bi3.25La0.75Ti3O12 (BL) based thin films are prepared by chemical solution deposition for energy storage. Ultrahigh energy storage with a recoverable energy density Ure of 54.9 J/cm3 and an efficiency η of 74.4% is observed in the bilayered BF/BL thin films. Further improvement of energy storage is realized in trilayered BL/BF/BL thin films with a Ure of 65.5 J/cm3 and an efficiency η of 74.2% at an electric field of 2753 kV/cm as well as excellent fatigue endurance up to 109 cycles. The results suggest that BF/BL based thin films can be used as lead-free TFFCs in energy storage applications.

Violet phosphorus (VP) is a stable layered van der Waals phosphorus allotrope with unique electronic and optoelectronic properties. In this study, 2D VP nanosheets (NSs) are prepared by liquid phase exfoliation (LPE) method under ambient conditions. The prepared VP NSs are characterized and utilized for photoelectrochemical (PEC)-type photodetector (PD). The systematic PEC measurements reveal that the as-prepared VP-based PD shows tunable photo-response activities from ultraviolet to visible region. A current density of 0.52 µA cm −2 , a photo-responsivity of 31.70 µA W −1 , and a detectivity of 7.92 × 10 10 Jones can be obtained in 1.0 m KOH under 350 nm irradiation at 0 V, revealing the good self-powered capability of VP-based PD. Furthermore, the cycle and time stability tests exhibit the good chemical and environmental stability of the as-prepared PD via processing 10 000 s on/off switching and placing after one month. It is expected that this work can offer an understanding of a PEC-type VP NSs-based PD, and highlight the further promising applications of 2D VP NSs for other optoelectronic devices.

Multiferroic BiFeO3 (BFO) thin films with a thickness larger than 400 nm are grown on solution-derived LaNiO3 coated Si substrates via chemical solution deposition.

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