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SUMMARY:Development of Solid-State Solar Thermal Fuels - Dr. John Griffin\
 , Lancaster University
DTSTART:20231027T130000Z
DTEND:20231027T140000Z
UID:TALK204538@talks.cam.ac.uk
CONTACT:Sharon Connor
DESCRIPTION:Solar thermal fuels (STFs) are an emerging class of materials 
 that store light energy in strained bonding configurations of photorespons
 ive molecules and release it on demand as heat. They have potential applic
 ations as source of heat energy in technology and architecture. A key requ
 irement for STFs to function is the availability of free volume for the ph
 otoresponsive molecules to change structure in response to light. For this
  reason\, many STFs have been developed in the solution state\, although t
 his can present limitations in terms of storage\, containment and energy d
 ensity. For some applications solid-state STFs would be desirable\, althou
 gh these are challenging to design owing to the lack of steric freedom in 
 dense phases.\n\nIn this work\, we have been developing solid-state STFs b
 ased on molecular photoswitches such as azobenzene confined within metal-o
 rganic frameworks (MOFs).[1-3] Using a combination of X-ray diffraction an
 d solid-state NMR we are able to monitor guest-induced breathing upon load
 ing the well-known framework DMOF-1 with azobenzene\, with an associated p
 hase transition enthalpy. NMR measurements show both the guest and framewo
 rk are highly dynamic at ambient temperature. When the composite is expose
 d to 365 nm light we observe isomerisation to the cisisomer\, which is als
 o highly mobile. Upon thermally triggered reconversion to the ground-state
  trans isomer\, we can demonstrate bulk solar energy storage and thermal e
 nergy release. By tailoring the guest and framework structure\, we are abl
 e to optimise the energy density to reach a maximum value of 100 J g–1 w
 hich is in the range of other organic phase transition materials and sets 
 a precedent for the further development of light-harvesting materials for 
 thermal energy storage.\n\n1. K. Griffiths\, N. R. Halcovitch\, J. M. Grif
 fin\, Chem. Mater. 2020\, 32\, 9925-9936.\n\n2. K. Griffiths\, N. R. Halco
 vitch\, J. M. Griffin\, Inorg. Chem. 2021\, 60\, 12950-12960.\n\n3. K. Gri
 ffiths\, N. R. Halcovitch\, J. M. Griffin\, Chem. Sci. 2022\, 13\, 3014-30
 19.\n\n
LOCATION:Dept of Chemistry\, Wolfson Lecture Theatre 
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