Temperature-, excitation wavelength-, and excitation power-dependent photoluminescence (PL) spectroscopy have been utilized to investigate the orientation-modulated near band edge emission (NBE) and deep level emission (DLE) of ZnO single crystals (SCs). The near-band-edge emission of ZnO SC with orientation exhibits strong and sharp emission intensity with suppressed deep level defects (mostly caused by oxygen vacancies V_o). Furthermore, Raman analysis reveals that orientation has dominant E₂ (high) and E₂ (low) modes, indicating that this direction has better crystallinity. At low temperature, the neutral donor-to-bound exciton (D^oX) transition dominates, regardless of the orientation, according to the temperature-dependent PL spectra. Moreover, free-exciton (FX) transition emerges at higher temperatures in all orientations. The PL intensity dependence on the excitation power has been described in terms of power-law (I~L^α). Our results demonstrate that the α for , , and is (1.148), (1.180), and (1.184) respectively. In short, the comprehensive PL analysis suggests that D^oX transitions are dominant in the NBE region, whereas oxygen vacancies (V_o) are the dominant deep levels in ZnO. In addition, the orientation contains fewer V_o-related defects with intense excitonic emission in the near band edge region than other counterparts, even at high temperature (~543 K). These results indicate that growth direction is favorable for fabricating ZnO-based highly efficient optoelectronic devices.

Cobalt-iron (CoFe) layered double hydroxides (LDHs) have received much interest for supercapacitors (SCs) because of their ion-insertable layer structure. However, there is still a need for more effort to increase their potential window and overall electrochemical energy storage capability as SC electrodes. In this work, we present a straightforward approach to synthesizing CoFe-LDHs on zinc oxide seeded carbon cloth (ZnO@CC) via a one-step hydrothermal reaction; the obtained electrode is denoted as CoFe-LDH@ZnO@CC. The electrochemical energy storage properties of CoFe-LDH@ZnO@CC are tested as an anode material using a three-electrode setup for SC applications in 1 M Na₂SO₄ electrolyte. It can operate in a wider potential window reaching up to 1.6 V, exceeding most previously reported anode materials. The CoFe-LDH@ZnO@CC displayed capacitive charge storage accounting for 76% of the total charge stored at 20 mV/s. The CoFe-LDH@ZnO@CC anode delivered a maximum capacitance of 299.8 F/g at 2 A/g, outstanding cycle stability, and retained 97.7% of the initial capacitance value for 5000 cycles at 16 A/g. This study introduces a new strategy for structurally designing electroactive materials for energy storage devices, which might be useful as an anode for SCs.

In order to increase the industrial appeal of solid‐state batteries (SSBs) based on garnet Li ₇ La ₃ Zr ₂ O ₁₂ (LLZO), the possibility of manufacturing them using scalable production processes such as tape casting must be demonstrated. In particular, the scalable production of thick, high‐capacity oxide‐ceramic composite cathodes based on Ni‐rich LiNi _x Mn _y Co _z O ₂ (NMC) remains a key challenge on the path to realizing ceramic SSBs with competitive energy densities. The limited thermal compatibility between NMC and LLZO during sintering requires the use of a sintering aid such as Li ₃ BO ₃ (LBO), which, however, impairs the rheological stability of tape casting slurries. In this work, we have developed a new tape‐casting process for thick oxide‐ceramic composite cathodes by establishing a slurry formulation that is compatible with multiphase cathode compositions and enables the reproducible fabrication of composite NMC cathode tapes with high active material loading. Two cathode configurations are investigated: NMC‐LLZO‐LBO composite cathodes, where LLZO serves as the catholyte, and LLZO‐free NMC‐LBO cathodes. After cosintering, the residual porosity of the ceramic cathodes is infiltrated with a polymer electrolyte with and without conductive carbon additives to form hybrid polymer‐ceramic SSBs. By systematically correlating cathode chemistry, secondary phase formation, and electrochemical performance, this study demonstrates how cathode chemistry and the balance between ionic and electronic transport pathways influence capacity utilization and cycle stability in thick, tape‐cast NMC‐based composite cathodes.