Periodic Reporting for period 3 - PROMOFS (Nanoengineering and Processing of Metal-Organic Framework Composites for Photonic Sensors)
Berichtszeitraum: 2021-04-01 bis 2022-09-30
The PROMOFS project lies is in the field of nanoporous materials engineering. It is focused on the discovery, characterisation, and application of metal-organic frameworks (MOFs) as an innovative platform to afford disruptive photonics sensing technology. Compared to the traditional materials (e.g. metal oxides and nitrides), MOFs offer several key advantages. The (hybrid) inorganic-organic structures of MOFs offer a huge prospect to tune the physical and chemical properties to enable the engineering of bespoke applications. Their 3D crystalline framework meant there is long-range periodicity, translating into continuous pathways to facilitate energy transfer and tuneable transport mechanisms. Significantly, the nanoscale pores within MOFs can be used as a vessel to host functional guests, in this context: to confine light-emitting guests for creating unconventional Guest@MOF photoluminescent composite systems fit for technological applications.
The overall objectives are the following:
(i) To establish facile processing of new Guest@MOF photonic materials and composite systems, utilising in-situ nanoscale confinement strategy combined with supramolecular processing strategies
(ii) To characterise photophysical and photochemical properties controlling the performance of Guest@MOF systems, and to understand fundamental mechanisms at the nanoscale
(iii) To employ ab initio computational modelling to gain deeper insights into host-guest interactions, and to predict structure-property relations informing the design of bespoke materials and Guest@MOF composite
(iv) To innovate in materials patterning technology for versatile materials-to-device manufacturing processes, employing 3D printing and electrospinning methodologies
(v) To apply Guest@MOF materials in nanoengineering of tuneable photonics sensors, paving the way to the engineering of mechanochromic, thermochromic, solvatochromic sensors
(vi) To quantify and enhance stability of Guest@MOF materials to yield long term stability aimed at practical applications
The overall objectives are the following:
(i) To establish facile processing of new Guest@MOF photonic materials and composite systems, utilising in-situ nanoscale confinement strategy combined with supramolecular processing strategies
(ii) To characterise photophysical and photochemical properties controlling the performance of Guest@MOF systems, and to understand fundamental mechanisms at the nanoscale
(iii) To employ ab initio computational modelling to gain deeper insights into host-guest interactions, and to predict structure-property relations informing the design of bespoke materials and Guest@MOF composite
(iv) To innovate in materials patterning technology for versatile materials-to-device manufacturing processes, employing 3D printing and electrospinning methodologies
(v) To apply Guest@MOF materials in nanoengineering of tuneable photonics sensors, paving the way to the engineering of mechanochromic, thermochromic, solvatochromic sensors
(vi) To quantify and enhance stability of Guest@MOF materials to yield long term stability aimed at practical applications
Main results achieved so far have been published in the following articles:
(i) Reproducible fabrication and scale up of designer luminescent guest@MOF nanomaterials for disruptive sensing technology and electroluminescence. Silver-based MOF with eco-friendly processing for smart sensors and solid-state lighting.
• M. Gutiérrez, C. Martín, B.E. Souza, M. Van der Auweraer, J. Hofkens, and J.C. Tan, "Highly Luminescent Silver-Based MOFs: From scalable eco-friendly synthesis to photonics sensors and electroluminescent devices", Applied Materials Today, 21, 100817 (2020).
• Y. Zhang, M. Gutiérrez, A.K. Chaudhari, and J.C. Tan, "Dye-encapsulated zeolitic imidazolate framework (ZIF-71) for fluorochromic sensing of pressure, temperature, and volatile solvents", ACS Applied Materials & Interfaces, 12, 37477-37488 (2020).
(ii) Nanoscale characterisation of luminescent Guest@MOF crystals to pinpoint confinement of guest molecules in the nanosized pore.
• A.F. Möslein, M. Gutiérrez, B. Cohen, and J.C.Tan "Near-field infrared nanospectroscopy reveals guest confinement in metal-organic framework single crystals", Nano Letters, 20, 7446−7454 (2020)
(iii) 3D printing of a liquid photopolymer to fabricate a luminescent composite incorporating dual-guest fluorophores nanoconfined in a MOF host. Engineering of Guest@MOF thin films adhered on a flexible transparent substrate for device applications.
• A.K. Chaudhari and J.C. Tan, "Dual-Guest Functionalised ZIF-8 Framework for 3D Printing White Light-Emitting Composites", Advanced Optical Materials, 8, 1901912 (2020).
• A.K. Chaudhari, B.E. Souza, and J.C. Tan, "Electrochromic Thin Films of Zn-based MOF-74 Nanocrystals Facilely Grown on Flexible Conducting Substrates at Room Temperature", APL Materials, 7, 081101 (2019).
(iv) Enhanced photostability of Guest@MOF systems.
• M. Gutiérrez, C. Martín, M. Van der Auweraer, J. Hofkens, and J.C. Tan, "Electroluminescent Guest@MOF Nanoparticles for Thin Film Optoelectronics and Solid‐State Lighting", Advanced Optical Materials, 8, 2000670 (2020).
(i) Reproducible fabrication and scale up of designer luminescent guest@MOF nanomaterials for disruptive sensing technology and electroluminescence. Silver-based MOF with eco-friendly processing for smart sensors and solid-state lighting.
• M. Gutiérrez, C. Martín, B.E. Souza, M. Van der Auweraer, J. Hofkens, and J.C. Tan, "Highly Luminescent Silver-Based MOFs: From scalable eco-friendly synthesis to photonics sensors and electroluminescent devices", Applied Materials Today, 21, 100817 (2020).
• Y. Zhang, M. Gutiérrez, A.K. Chaudhari, and J.C. Tan, "Dye-encapsulated zeolitic imidazolate framework (ZIF-71) for fluorochromic sensing of pressure, temperature, and volatile solvents", ACS Applied Materials & Interfaces, 12, 37477-37488 (2020).
(ii) Nanoscale characterisation of luminescent Guest@MOF crystals to pinpoint confinement of guest molecules in the nanosized pore.
• A.F. Möslein, M. Gutiérrez, B. Cohen, and J.C.Tan "Near-field infrared nanospectroscopy reveals guest confinement in metal-organic framework single crystals", Nano Letters, 20, 7446−7454 (2020)
(iii) 3D printing of a liquid photopolymer to fabricate a luminescent composite incorporating dual-guest fluorophores nanoconfined in a MOF host. Engineering of Guest@MOF thin films adhered on a flexible transparent substrate for device applications.
• A.K. Chaudhari and J.C. Tan, "Dual-Guest Functionalised ZIF-8 Framework for 3D Printing White Light-Emitting Composites", Advanced Optical Materials, 8, 1901912 (2020).
• A.K. Chaudhari, B.E. Souza, and J.C. Tan, "Electrochromic Thin Films of Zn-based MOF-74 Nanocrystals Facilely Grown on Flexible Conducting Substrates at Room Temperature", APL Materials, 7, 081101 (2019).
(iv) Enhanced photostability of Guest@MOF systems.
• M. Gutiérrez, C. Martín, M. Van der Auweraer, J. Hofkens, and J.C. Tan, "Electroluminescent Guest@MOF Nanoparticles for Thin Film Optoelectronics and Solid‐State Lighting", Advanced Optical Materials, 8, 2000670 (2020).
Major discoveries to date include the following:
(i) Near-field infrared nanospectroscopy (nanoFTIR) has been demonstrated, for the first time, to probe the local vibrational spectra of a MOF crystal, spatially resolved to 20 nm. For luminescent Guest@MOF composites, we have overcome the challenge to unambiguously pinpoint whether the guest molecules are truly encapsulated in the MOF pores, or, only confined on the crystal surface. The study has been published in Nano Letters, 20, 7446−7454 (2020).
(ii) Discovery of silver-based MOFs (termed OX-2) exhibiting a high quantum yield, excellent luminescent sensing capabilities and electroluminescent properties, the results have been published in Applied Materials Today, 21, 100817 (2020). OX-2 can be bulk synthesised in water under ambient conditions to easily yield 10-g scale materials. This exciting sensor material has been patented for future commercialisation by Oxford University Innovation.
(iii) Guest-tuneable dielectric sensing using a single crystal of MOF, published in Advanced Materials Interfaces, 7, 2000408 (2020). In this study, we demonstrate the sensing and discrimination of the vapours of polar and non-polar molecules. Uniquely, the sensing has been accomplished by tracking the transient dielectric response of the single crystal upon guest sorption and desorption cycles by alternating current signals. Because the dielectric properties are omnipresent in MOF crystals, this strategy is advantageous against competing methodologies relying on resistive and fluorescent mechanisms.
(i) Near-field infrared nanospectroscopy (nanoFTIR) has been demonstrated, for the first time, to probe the local vibrational spectra of a MOF crystal, spatially resolved to 20 nm. For luminescent Guest@MOF composites, we have overcome the challenge to unambiguously pinpoint whether the guest molecules are truly encapsulated in the MOF pores, or, only confined on the crystal surface. The study has been published in Nano Letters, 20, 7446−7454 (2020).
(ii) Discovery of silver-based MOFs (termed OX-2) exhibiting a high quantum yield, excellent luminescent sensing capabilities and electroluminescent properties, the results have been published in Applied Materials Today, 21, 100817 (2020). OX-2 can be bulk synthesised in water under ambient conditions to easily yield 10-g scale materials. This exciting sensor material has been patented for future commercialisation by Oxford University Innovation.
(iii) Guest-tuneable dielectric sensing using a single crystal of MOF, published in Advanced Materials Interfaces, 7, 2000408 (2020). In this study, we demonstrate the sensing and discrimination of the vapours of polar and non-polar molecules. Uniquely, the sensing has been accomplished by tracking the transient dielectric response of the single crystal upon guest sorption and desorption cycles by alternating current signals. Because the dielectric properties are omnipresent in MOF crystals, this strategy is advantageous against competing methodologies relying on resistive and fluorescent mechanisms.