Using carbon‐based super black coatings on optical devices can achieve superior stray light suppression for applications in astronomy. For the first time, the work presents carbon nanofiber‐based black coating on commercial anodized Al(6061), which facilitates the development of a highly effective route to directly integrate the carbon‐based material on the common substrate for optical baffles. The scalable and available structural engineering effect is synergized with the anodized Al(6061) coating with black dye composed of nickel catalyst and the intrinsic broadband light absorption of the CVD‐grown carbon material to ultimately achieve a superior broadband light absorber. Nickel catalysts embedded in anodized Al(6061) offer a practical pathway for carbon nanofiber growth through CVD without additional stacked catalysts. The CVD‐growing mechanism and CNF nanostructures are demonstrated through TEM and EDS element mapping, SEM, and Raman spectroscopy. CNF‐grown Al(6061) substrates offer above 99% broadband light absorption and low light reflectance below 1% in UV–vis–NIR and mid–IR ranges. This facile approach has been useful for super black coating on Al(6061)‐based complicated sculptures, such as concave substrate and an optical baffle. These results have demonstrated a facile method that can significantly impact the industrial scaling‐up of high‐quality, super‐black coating on spaceborne devices.

Here, we present a novel protocol concept for quantifying the cooling performance of particle-based radiative cooling (PBRC). PBRC, known for its high flexibility and scalability, emerges as a promising method for practical applications. The cooling power, one of the cooling performance indexes, is the typical quantitative performance index, representing its cooling capability at the surface. One of the primary obstacles to predicting cooling power is the difficulty of simulating the non-uniform size and shape of micro-nanoparticles in the PBRC film. The present work aims to develop an accurate protocol for predicting the cooling power of PBRC film using image processing and regression analysis techniques. Specifically, the protocol considers the particle size distribution through circle object detection on SEM images and determines the probability density function based on a chi-square test. To validate the proposed protocol, a PBRC structure with PDMS/Al₂O₃ micro-nanoparticles is fabricated, and the proposed protocol precisely predicts the measured cooling power with a 7.8% error. Through this validation, the proposed protocol proves its potential and reliability for the design of PBRC.

Although perovskite-structured materials have primarily been widely employed in solar cell applications, limited studies have been conducted in the field of electrorheology (ER). In this study, various halide perovskite materials, including FAPbBr₃, FAPbI₃, MAPbBr₃, MAPbI₃, CsPbBr₃, and CsPbI₃ were synthesized for the first time to evaluate their applicability in ER for the first time. Initially, the morphological and chemical properties of these materials were characterized to confirm the successful formation of the perovskite structures. In addition, the as-synthesized halide perovskite materials were dispersed in silicone oil (3.0 wt %) to evaluate their suitability as dispersants in ER fluids. Among these, the CsPbI₃-based ER fluid exhibited the optimal dielectric properties and the greatest dispersion stability of the various systems examined. In ER applications, the CsPbI₃-based ER fluid demonstrated the highest ER performance, achieving a shear stress of 99.4 Pa, owing to the synergistic effects of its intrinsic rod-like structure and dielectric properties, which promoted polarization. The aspect ratios of the CsPbI₃ rods were further controlled by modifying the synthetic process, resulting in the generation of both shorter and longer rods. Notably, ER fluids based on CsPbI₃ synthesized via a hydrothermal method yielded rod-like structures with a high aspect ratio of 20, leading to an enhanced ER activity of 128.0 Pa. These results highlight the potential of halide perovskite materials for use in ER applications.

In this study, we identify the origin of electronic flame-off (EFO) errors based on the type of rinse applied for the surface treatment of gold (Au) wires in the wire-bonding semiconductor packaging process. Hydrocarbon and silicone surfactants are commonly used for Au wire surface treatment, and five different 1.0 wt% rinse solutions with varying compositions are applied to the Au wire surface. To determine the origin of EFO errors, an experiment is conducted to examine the reactivity of the rinse-coated Au wires with silicon (Si)-containing dust, which is inevitably generated in the wire-bonding process. Optical microscopy and field-emission scanning electron microscopy show that a large amount of dust is adsorbed onto the surface of the Au wire coated with a Si-containing rinse. This is attributed to the Si component in the rinse, which interacts with the electric arc during the EFO process. Si–CH3 bonds break at a high thermal energy, thereby enabling the formation of low-activation-energy nonpolar σ bonds with Si-containing dust. As these defects negatively impact productivity and reliability, we suggest using Si-free organic rinses for Au wire surface treatment in the wire-bonding process to reduce the defect rates associated with contamination.