Hwan Kyu Kim

This study determines the ideal thermal treatment conditions for WO₃ films to optimize ion mobility, structural stability, and long-term cycling performance.

PEDOT counter electrodes, optimized via spin-coating a DMSO-dispersed solution from scalable synthesis, were evaluated for cobalt reduction in dye-sensitized solar cells. PEDOT was a superior electrocatalyst compared to Pt.

Dye‐sensitized solar cells (DSSCs)‐integrated Li‐ion batteries (LIBs) are considered a promising solution as a wireless power source for the increasing number of miniaturized portable devices and the internet of things (IoTs). However, DSSCs suffer from stability issues because of the using volatile electrolyte solvents that leak through the seal. To solve this problem, in this study, a polymer gel electrolyte based on the high‐boiling solvent 3‐methoxypropionitrile (bp = 164–165 °C) is used, and the backside of the cells are sealed by hot press using surlyn and Al foil. A highly stable and efficient counter electrode, Pt/porous carbon (Pt/PC), is also used to fabricate the devices, which show a high PCE of 25.7%–29.4% under the illumination of 500–2000 lux. The fabricated DSSC shows outstanding stability in the room condition and under the operating condition at 50 °C. A mini‐module of 13.3 cm², PCE of 22.9–23.3%, and P_max of 166.4–643.0 μW can recharge a LIB while powering an IoT device by producing an output greater than the IoT device consumes. The store charge can be used when the light source is cut off, indicating the reliability of the DSSC for photocharging the LIB as a wireless power source for IoT devices.

Photo‐rechargeable energy storage devices are appealing for substantial research attention because of their possible applications in the Internet of Things (IoT) and low‐powered miniaturized portable electronics. However, due to the incompatibility of the photovoltaics and energy storage systems (ESSs), the overall light‐to‐storage efficiency is limited under indoor light conditions. Herein, a porous carbon scaffold MnO‐Mn₃O₄/C microsphere‐based monolithic dye‐sensitized photo‐rechargeable asymmetric supercapacitor (DSPC) is fabricated. The integrated DSPC has a high areal specific capacitance of 281.9 mF cm⁻² at the discharge rate of 0.01 mA cm⁻². The light‐to‐electrical conversion efficiency of the DSSC is 27.6% under the 1000 lux compact fluorescent lamp (CFL). The DSPC shows an outstanding light‐to‐charge storage efficiency of 21.6%, which is higher than that reported ever. Furthermore, the fabricated polymer gel electrolyte‐based quasi‐solid state (QSS) DSPC shows similar overall conversion efficiency with superior cycling capability. This work shows a convenient fabrication process for a wireless power pack of interest with outstanding performance.

Despite significant progress in device performance, dye-sensitized solar cells (DSSCs) continue to fall short of their theoretical potential. Moreover, research in recent years needs to pay more attention to improving the device fabrication process. To achieve the theoretical efficiency limit, it is crucial to optimize the interface between the dye and TiO₂ nanoparticles in the entire device stack. Our study indicates that optimizing the structure or size of the coadsorbents and implementing a monolayer adsorption process can be an effective strategy to reduce charge recombination and enhance light-harvesting properties. Our research aims to develop a surface-coating adsorbent plan that controls the TiO₂ nanoparticle interface to achieve the radiative limit of power conversion efficiency (PCE). Specifically, we utilized 2-thiophenecarboxylic acid (THCA) or chenodeoxycholic acid (CDCA) as postinterfacial surface-coating adsorbents. Our results demonstrate that this approach effectively achieves the desired PCE limit. Combined with the coadsorbent structure engineering and interface optimization, the device increased the packing area on the TiO₂ nanoparticles' surface, reaching an improved PCE of over 13.17% under simulated sunlight (1.5G), which is the highest efficiency of a porphyrin single dye-based DSSC. In particular, this practical approach was also applied to a large-area DSSC with an area of 3 cm², yielding a remarkable PCE of 9.04%. Furthermore, when applied to a polymer gel electrolyte, this novel approach recorded the highest PCE of 11.16% with a long-term operational stability of up to 1000 h for the quasi-solid-state DSSCs. Our research findings provide a promising avenue for achieving high-performance DSSCs with ease of access and demonstrate practical applications as alternatives to conventional power sources.