Halide perovskite nanowires (HP‐NWs) exhibit fascinating optical properties, making them attractive for advanced technologies. However, instability and lack of an effective synthetic protocol limit their commercialization. To address this, nanoporous anodized aluminum oxide (AAO) metamaterial is used as templates for the growth of CsPbBr₃ NW arrays. AAO functions as a growth template and a stabilizing medium. The NW array exhibits strong light‐trapping ability, and the pore geometric features (pore radius‐R and distance between pores‐d) can potentially enhance the light‐matter interactions (LMI). The impact of R and d on LMI within the AAO/CsPbBr₃ system using theoretical finite difference time domain (FDTD) simulations is demonstrated for the first time. Optimal LMI is observed with _R = d = 25 nm and 50 nm. Ligand‐free synthesis of CsPbBr₃ NW arrays via spin‐coating, drop‐casting, and inverse temperature crystallization (ITC) is reported. While spin‐coating and drop‐casting results in poor pore filling, the modified ITC method achieves >90% pore filling with significant NW lengths. These findings highlight the potential of AAO templates for protecting CsPbBr3 and addressing synthetic challenges in HPs and other semiconductor NW arrays. This study provides key insights for LMI in HPs and advances NW array‐based optical devices and renewable energy applications.

Rapid industrialization and unlimited human activities have led to severe environmental challenges, particularly water contamination by persistent organic pollutants, posing serious risks to ecosystems and human health. Photocatalytic technology offers a sustainable remediation for pollutant degradation using solar energy. In this study, ultrathin carbon‐encapsulated ZnO nanoparticles, ZnO@C are employed, as an efficient photocatalyst, using methylene blue and methyl orange as model pollutants. The carbon has a favorable band alignment with ZnO for efficient charge transfer. In fact, the optical absorption studies and finite‐difference time‐domain simulations establish an enhanced absorption and light–matter interaction upon thin uniform carbon encapsulation. Photoluminescence quenching (≈80%) indicates reduced electron–hole recombination, facilitated by defect‐induced charge transfer from ZnO to carbon. Electron paramagnetic resonance measurements identify superoxide radicals (O ₂ • ⁻ ) as the dominant reactive species, driving a selective radical‐mediated degradation pathway. Compared to pristine ZnO, the ZnO@C system exhibits over 60% higher degradation efficiency. Liquid chromatography–mass spectrometry analyses elucidate the sequential degradation pathway driven by O ₂ • ⁻ . The ZnO@C demonstrates excellent photostability and reusability across multiple cycles, with a sixfold increase in kinetic rate constants over pristine ZnO. These improvements highlight the potential of ZnO@C core@shell nanostructures for sustainable environmental remediation.

Halide perovskites (HPs) have gained significant interest in the scientific and technological sectors due to their unique optical, catalytic, and electrical characteristics. However, the HPs are prone to decomposition when exposed to air, oxygen, or heat. The instability of HP materials limits their commercialization, prompting significant efforts to address and overcome these limitations. Meanwhile, the transition metal dichalcogenides, such as MoS2, are chemically stable and offer versatile properties suitable for electronic, optical, and catalytic applications. The layered structure of MoS2 allows for the development of protective coatings for other nanoparticles. In this study, we successfully synthesized a novel CsPbBr3@MoS2 core-shell nanostructure (CS-NS) by enveloping CsPbBr3 within a MoS2 shell for the first time. We also demonstrate a significant enhancement in the stability of CS-NSs when dispersed in polar solvents for extended periods. Remarkably, the hybrid CS-NSs exhibits an absorption spectrum closely aligned with MoS2 and photoluminescence (PL) quenching, indicating the potential for charge or energy transfer. We used finite difference time domain (FDTD) simulations to evaluate the efficiency of CS-NS-based solar cells and their potential for performance enhancement. This groundbreaking CS-NSs represents a significant advancement in harnessing halide perovskite materials for applications in photovoltaics and various optoelectronic devices.

Halide perovskites (HPs) exhibit outstanding optoelectronic properties, making them highly attractive for advanced photonic and electronic applications. Among them, cesium lead bromide (CsPbBr₃) exhibits high photoluminescence efficiency, narrow emission linewidths, and excellent color purity, making it suitable for light-emitting diodes, photodetectors, scintillators, and lasers. However, its practical application remains limited by intrinsic instability and environmental stressors such as moisture, heat, oxygen, and illumination. This review discusses the fundamental degradation mechanisms in HPs, using CsPbBr₃ as a representative system, primarily in nanocrystals (NCs), while also considering thin-film and bulk forms. Intrinsic instability arises from the soft ionic lattice, a relatively low tolerance factor, and anharmonic lattice dynamics, which promote defect formation, ion migration, and structural distortion. Low activation energies for ionic transport enable migration of halide (Br⁻) and A-site (Cs⁺) ions, leading to defect accumulation, non-radiative recombination, and phase instability. In NCs, surface-dominated effects further accelerate degradation, driven by high defect densities and ligand desorption. Extrinsic factors promote degradation through hydrolysis, photoinduced defect formation, radical-driven reactions, and transformation into secondary phases. These processes can be intensified when multiple environmental stressors act simultaneously, reducing operational stability. These processes form a coupled, condition-dependent degradation network. Their interactions and relative contributions depend on the material form and environmental or operational conditions. Overall, this review highlights the interconnected roles of lattice dynamics, defect formation, ionic transport, and environmental interactions in governing the instability of CsPbBr₃-based HPs.