Fabricating functional Luminescent metal-organic framework nanosheet materials

Thesis

Luminescent metal-organic frameworks (LMOFs) are promising materials for myriad chromatic based applications, from organic-light emitting diodes (OLEDs) to sensors and optoelectronics. This arises from the rational tunability of MOFs, which imparts control over material properties so they can be tailored to particular use cases. Yet, the 3D nature of LMOFs creates challenges for optical transparency, sensing sensitivity, and device integration. Metal-organic framework 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. This integrated thesis establishes luminescent MONs (LMONs) as next-generation MOF materials for lighting, indicators, and sensors (Chapter 1). Chapter 2 introduces the emerging field of MONs, and the techniques employed in this work to study the photophysical properties of materials. In Chapter 3, a robust in situ guest incorporation strategy for luminescent dyes in MONs is established. The incorporation of red, green, and blue emitters in various combinations endowed MONs with new luminescent properties, including white light emission (WLE), that could be tuned based on guest content and arrangement. The improved fabricability available with MONs is demonstrated in Chapter 4, by realising aerosol jet printing as a new methodology for creating fine-scale MOF-based luminescent thin film patterns and micro-structures. Chapter 5 expands the concept of luminescent guest@MONs to thicker (~ 200 nm) 2D ZIF-L materials, allowing the benefits of 2D guest intercalation to be coupled with more regular porosity. The result was increased predictability of structure- property relationships that could be used to better tune luminescent behaviours, along with an ability to grow in situ luminescent ZIF-L oriented films. A critical review of the studies in this thesis is provided in Chapter 6, accompanied with an outlook for the future directions of LMON-based optical devices.

Authors: Sherman, DA

• DOI: 10.5287/ora-xv8ak1mr9
• Type of award: DPhil
• Level of award: Doctoral
• Awarding institution: University of Oxford
• Language: English
• Keywords: metal-organic frameworks; luminescent materials; metal-organic nanosheets; porous materials; inkjet printing
• Subjects: Engineering science; Materials chemistry