Electron dynamics in transition metal oxides Geoff …...Electron dynamics in transition metal...
Transcript of Electron dynamics in transition metal oxides Geoff …...Electron dynamics in transition metal...
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• Applications in photovoltaics, photochemistry and catalysis.
• Large band gap of a few electron volts. ü TiO2 band gap: ~3 eV ü Photocatalysis and light harvesting
Time-resolved photoelectron spectroscopy with XUV. • Dynamics of conduction band (CB)
and valence band (VB) • Selective excitations
ü VBàCB transition ü Polaron excitation
Electron dynamics in transition metal oxides Geoff Thornton, UCL Time Resolved Photoemission
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Electron dynamics in transition metal oxides Geoff Thornton, UCL Time Resolved Photoemission
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Defect state excitation • Polaron: photon-assist hopping in a
time scale of 50 fs
defect states
YZhang,DPayne,C.L.Pang,CCacho,R.T.Chapman,ESpringate,H.H.Fielding,G.Thornton,J.Phys.Chem.Lett.2019,10,5265
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Electron dynamics in transition metal oxides Geoff Thornton, UCL Time Resolved Photoemission
Future Prospects: • C,N,O core level photoemission to investigate water chemistry,
photodegradation on transition metal oxides—EuXFEL up to 1 keV • Eg Hybrid perovskites, element-specific recombination paths and charge
transfer to electron and hole collectors
• Time resolved photoelectron diffraction to follow electron path following pump pulse
• Tender X-rays (4 keV) and HAXPES measurements at liquid solid interfaces for hybrid perovskite/ TiO2 interfaces