Zhigang Wang

Lithium-ion batteries (LIBs) can benefit from transition metal oxides as anode materials because of their high theoretical capacities. However, volume expansion during cycling restricts their application. In this study, cobalt phthalocyanine modified by tert-butyl groups (tBuCoNc), with "steric-electronic" dual regulation, is used. The tert-butyl groups serve as a bridge for molecular design and property optimization. The cobalt oxide/nitrogen-doped graphene composites are constructed. The conjugated planar structure enhances charge transport, while tert-butyl substituents provide steric hindrance that improves structural stability and prevents nanoparticle aggregation. Upon pyrolysis, cobalt centers are transformed into uniformly dispersed cobalt oxide nanocrystals within a nitrogen-doped carbon matrix, offering abundant active sites that facilitate ion diffusion and electrolyte contact. The final composite, formed via π-π stacking and thermal treatment, exhibits strong synergistic effects between cobalt oxide and N-doped graphene. Electrochemical testing reveals an impressive initial discharge capacity of 1556.5 mAh g^-1 at 100 mA g^-1 and 741.1 mAh g^-1 after 100 cycles, highlighting its potential as a high-performance anode material for next-generation LIBs.

Copper(I) halides are promising candidates for advanced optoelectronics, such as white-light-emitting diodes (WLEDs), scintillators, and photodetectors. Designing and synthesizing low-dimensional hybrid copper halides with blue-light excitation remains an enormous challenge. Herein, we have prepared two one-dimensional (1D) hybrid Cu(I)-based metal iodides, namely, (C₆H₇N)CuI and (C₆H₈N)CuI₂ single crystals, by deliberately adjusting the ratio of the reactants 4-methylpyridine (4-MePy) and CuI. (C₆H₇N)CuI crystals are nonluminous, while (C₆H₈N)CuI₂ crystals exhibit an unusual yellow emission with a broad excitation band in the range of 260-500 nm Furthermore, a prototypical WLED is fabricated by combining a commercial 430 nm blue chip and (C₆H₈N)CuI₂ phosphor, which exhibits a correlated color temperature (CCT) of 5645 K and a CIE color coordinate of (0.329, 0.334), thus demonstrating potential application for white lighting. Remarkably, (C₆H₈N)CuI₂ crystals emit red fluorescence upon adsorption of methanol but fail for all other alcohols. Notably, the initial yellow luminescence can be recovered upon volatilization of methanol from the crystals, thus achieving a reversible photoluminescence switching. This work not only presents an important reference of blue-light-excitable hybrid Cu(I)-based metal iodide phosphor for WLEDs but also provides an intriguing fluorescence sensor for the reversible detection of methanol.

Long persistent luminescence (PersL) materials have revolutionized many fields of optoelectronics and photonics due to their applications in anticounterfeiting, information encryption, and in vivo bioimaging. Here, we reported a novel PersL crystal prepared by the heterovalent doping of Sb³⁺ into perovskite tetragonal phase RbCdCl₃, comparing with the pristine non-perovskite orthorhombic phase analogue without PersL property. Surprisingly, under the UV light irradiation, the title crystals concurrently exhibit green ultralong PersL (>2400 s), high photoluminescence quantum yield (49.1%), and antithermal quenching in the range from 148 to 328 K. It was revealed by experimental results and theoretical analyses that green ultralong PersL and antithermal quenching of perovskite-phase RbCdCl₃/Sb³⁺ crystals originate from the electron transition between the 5s² level of the dopant Sb³⁺ and the electronic defect-induced trap states. Enlightened by the excellent optical properties, the tetragonal perovskite-phase RbCdCl₃/Sb³⁺ PersL materials show promising application prospects in anticounterfeiting and encryption of information.

Owing to the exterior self-trapped excitons (STEs) with adjustable fluorescence beams, low-dimensional ns²-metal halides have recently received considerable attention in solid-state light-emitting applications. However, the photoluminescence (PL) mechanism in metal halides remains a major challenge in achieving high efficiency and controllable PL properties because the excited-state energy of ns² conformational ions varies inhomogeneously with their coordination environments. Here, a novel zero-dimensional (0D) lead-free bismuth-based Rb₃BiCl₆·0.5H₂O crystal was reported as a pristine crystal to modulate the optical properties. By doping Sb³⁺ ions with 5s² electrons into Rb₃BiCl₆·0.5H₂O crystals, bright orange emission at room temperature was obtained with a photoluminescence quantum yield of 39.7%. Optical characterizations and theoretical studies show that the Sb³⁺ doping can suppress the strong exciton-phonon coupling, optimize the electronic energy band structure, improve the thermal activation energy, soften the structural lattice of the host crystals, deepen the STE states, and ultimately lead to strong photoluminescence. This work manifests a fruitful manipulation in ripening bismuth-based halides with high-efficiency PL properties, and the PL enhancement mechanisms will guide future research in the exploration of emerging luminescent materials.