Herein, we demonstrated a steric-hindrance-controlled laser switch in pure metal−organic framework (MOF) microcrystals. The well-faceted MOF microwires with aggregation-induced emission (AIE) lumnogens as linkers function as typical Fabry−Peŕot microlasers. The steric hindrance around the AIE linkers can be reduced by the loss of guest molecules, which lead to the enhanced rotation of linkers with red-shifted gain behavior. On this basis, the gain region was readily switched through changing the steric hindrance via the desorption/adsorption of guests. As a result, the reversible switching of the dual-wavelength lasing from MOF microwires was achieved. The results provide a promising route to the development of versatile micro-/nanolasers with desired applications.

Porous organic frameworks have emerged as the promising platforms to construct tunable microlasers. Most of these microlasers are achieved from metal–organic frameworks via meticulously accommodating the laser dyes with the sacrifice of the pore space, yet they often suffer from the obstacles of either relatively limited gain concentration or sophisticated fabrication techniques. Herein, we reported on the first hydrogen-bonded organic framework (HOF) microlasers with color-tunable performance based on conformation-dependent stimulated emissions. Two types of HOF microcrystals with the same gain lumnogen as the building block were synthesized via a temperature-controlled self-assembly method. The distinct frameworks offer different conformations of the gain building block, which lead to great impacts on their conjugation degrees and excited-state processes, resulting in remarkably distinct emission colors (blue and green). Accordingly, blue/green-color lasing actions were achieved in these two types of HOFs based on well-faceted assembled wire-like cavities. These results offer a deep insight on the exploitation of HOF-based miniaturized lasers with desired nanophotonics performances.

Porous organic materials (POMs) have shown great potential for fabricating tunable miniaturized lasers. However, most pure-POM micro/nanolasers are achieved via coordination interactions, during which strong charge exchanges inevitably destroy the intrinsic gain property and even lead to optical quenching, hindering their practical applications. Herein, we reported on an approach to realize hydrogen-bonded organic framework (HOF)-based in situ wavelength-switchable lasing based on the framework-shrinkage effect. A flexible HOF with reversible framework shrinkage was constructed from gain blocks with multiple rotors. The framework shrinkage of the HOF induced the in situ regulation on the conformation and conjugation degree of gain blocks, leading to distinct energy-level structures with blue/green-color gain emissions. Inspired by this, the in situ wavelength-switchable lasing from HOF microcrystals was achieved through reversibly controlling the framework shrinkage via the absorption/desorption of guests. The results offer useful insight into the use of flexible HOFs for exploiting miniaturized lasers with on-demand nanophotonics performance.

Metal−organic frameworks (MOFs) are an emerging kind of laser material, yet they remain a challenge in the controlled fabrication of crystal nanostructures with desired morphology for tuning their optical microcavities. Herein, the shape-engineering of pure MOF microlasers was demonstrated based on the coordination-mode-tailored method. The one-dimensional (1D) microwires and 2D microplates were selectively fabricated through changing the HCl concentration to tailor the coordination modes. Both the single-crystalline microwires and microplates with strong optical confinement functioned as low-threshold MOF microlasers. Moreover, distinct lasing behaviors of 1D and 2D MOF microcrystals confirm a typical shape-dependent microcavity effect: 1D microwires serve as Fabry−Peŕot (FP) resonators, and 2D microplates lead to the whispering-gallerymode (WGM) microcavities. These results provide a special pathway for the exploitation of MOF-based micro/nanolasers with on-demand functions.

One-dimensional (1D) metal–organic frameworks (MOFs) have shown great potential for designing more sensitive and smart stimuli-responsive photoluminescence metal–organic frameworks (PL-MOFs). Herein, we propose a strategy for constructing the 1D MOFs with tunable stimuli-responsive luminescence regions based on coordination-guided conformational locking. Two flexible 1D MOF microcrystals with trans- and cis-coordination modes, respectively, were synthesized by controlling the spatial constraint of solvents. The two 1D frameworks possess different conformation lockings of gain ligands, which have a great influence on the rotating restrictions and corresponding excited-state behaviors, generating the remarkably distinct color-tunable ranges (cyan-blue to green and cyan-blue to yellow, respectively). On this basis, the two 1D MOF materials, benefiting from the varied stimuli-responsive ranges, have displayed great potential in fulfilling the anticounterfeiting and information encryption applications. These results provide valuable guidance for the development of smart MOF-based stimuli-responsive materials in information identification and data encryption.