Luminescent Metal-Organic frameworks (LMOFs) are a promising organic light-emitting diode (OLED) alternative to silicate-based LEDs. Due to their tuneable structure and programmability, LMOFs can also be adapted for use within a range of optoelectronic devices for applications such as sensing. Yet, the 3D nature of LMOFs creates challenges for optical transparency, sensing sensitivity and device integration. Metal-Organic Nanosheets (MONs) have the potential to overcome these limitations by retaining the benefits of MOFs but in an atomically thin morphology of large planar dimensions.<br/><br/>Here, we report the first bottom-up synthesis of ZIF-7-III MONs via a facile low-energy salt-template synthesis. The resultant MONs are on average 2 nm in height and 20x10 μm wide. A guest@MOF approach was employed to intercalate fluorophores into the ZIF-7 nanosheets (Z7-NS). Various single guest Z7-NS systems were formed that exhibited emissive properties derived from the intercalated guests. Mixed-guest systems were also synthesised, resulting in a dual-guest yellow fluorescent material (DG-NS) and a triple-guest white-emitting material. Nano-FTIR, among other techniques, was employed for novel insight into locating the guest within the MON framework.<br/><br/>The materials exhibited improved quantum yield, stability and tunability compared to 3D counterpart materials. A 20-sample systematic analysis of the DG-NS revealed the mechanics of fluorescence, identifying the presence of inter-guest energy transfer dependent on the fluorophore ratio. A model was derived that quantifiably predicts the precise chromaticity of emission by the dual-guest NS dependent on the synthesis ratio of fluorophore guests. This enabled quantifiable tuneability of luminescence chromaticity and the definition of a unique “spectral fingerprint” subset of the visible spectrum unique to DG-NS; a critical finding for advanced luminescent tagging and sensing.

Ultra-thin quantifiably tuneable luminescent metal-organic nanosheets

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.