In this review, methods and mechanisms for enhancing photoelectrochemical water splitting using plasmonic Au nanoparticles are discussed in detail. In particular, we focus on the interface between Au particles and semiconductor photoelectrode.

To be viable for display applications, active structural colors must be electrically tunable, on/off switchable, and reversible. Independently controlling the first two functions, however, is difficult because of causality that ties the real and imaginary parts of the optical constants or changing overlap of fields during structural variations. Here, we demonstrate an active reflective color pixel that encompasses separate mechanisms to achieve both functions reversibly by electrochemically depositing and dissolving Cu inside the dielectric grating slits on a Pt electrode with ΔV < 3 V. Varying the modal interference via Cu occupancy in the slits changes the CIE space coverage by up to ~72% under cross-polarized imaging. In the same pixel, depolarization and absorption by the dissolving porous Cu switches the color off with a maximum contrast of ~97%. Exploiting these results, we demonstrate an active color-switching display and individually addressable on/off pixel matrix that highlights their potential in reflective display applications.

Resistive switching (RS) memory devices are gaining recognition as data storage devices due to the significant interest in their switching material, Halide perovskite (HP). The electrical characteristics include hysteresis in its current–voltage (I–V) relationship. It can be attributed to the production and migration of defects. This property allows HPs to be used as RS materials in memory devices. However, 3D HPs are vulnerable to moisture and the surrounding environment, making their devices more susceptible to deterioration. The potential of two-dimensional (2D)/quasi-2D HPs for optoelectronic applications has been recognized, making them a viable alternative to address current restrictions. Two-dimensional/quasi-2D HPs are created by including extended organic cations into the ABX₃ frameworks. By adjusting the number of HP layers, it is possible to control the optoelectronic properties to achieve specific features for certain applications. This article presents an overview of 2D/quasi-2D HPs, including their structures, binding energies, and charge transport, compared to 3D HPs. Next, we discuss the operational principles, RS modes (bipolar and unipolar switching), in RS memory devices. Finally, there have been notable and recent breakthroughs in developing RS memory systems using 2D/quasi-2D HPs.

One of the remarkable choices for active smart window technology is adopting a metal active layer via reversible metal electrodeposition (RME). As the metal layer efficiently blocks the solar energy gain, even a hundred-nanometer-thick scale, RME-based smart window has great attention. Recent developments are mainly focused on the various cases of electrolyte components and composition meeting technological standards. As metal nanostructures formed through the RME process involve plasmonic phenomena, advanced analysis, including plasmonic optics, which is beyond Beer–Lambert’s law, should be considered. However, as there is a lack of debates on the plasmonic optics applied to RME smart window technology, as research is mainly conducted through an exhaustive process. In this paper, in order to provide insight into the RME-based smart window development and alleviate the unclear part of plasmonic optics applied to the field, finite-difference time-domain electromagnetic simulations are conducted. In total, two extremely low-quality (Cr) and high-quality (Mg) plasmonic materials based on a nanoparticle array are considered as a metal medium. In addition, optical effects caused by the metal active layer, electrolyte, and nanoparticle embedment are investigated in detail. Overall simulations suggest that the effective refractive index is a decisive factor in the performance of RME-based smart windows.