| News
34th NARECOM - Photo/electrochemistry of oxide semiconductors rationalized by band energetics
Optimizing the n-doped oxide semiconductors in photocatalysis and photo-electrochemistry requires information about the electronic structure near the conduction band minimum. The information how to determine the band gap energies will be given by Prof. RNDr. Ladislav Kavan, DCs. from the Institute of Physical Chemistry of the CAS on Wednesday, March 20th, 2024 at 2:30 p.m. Join Zoom Meeting https://cesnet.zoom.us/j/92741141335
Photo/electrochemistry of oxide semiconductors rationalized by band energetics
Prof. RNDr. Ladislav Kavan, DCs.
J. Heyrovský Institute of Physical Chemistry of the CAS, Department of Electrochemical Materials
Abstract: Optimizing the n-doped oxide semiconductors in photocatalysis and photoelectrochemistry requires information about the electronic structure near the conduction band minimum. Yet, its analysis is challenging, sometimes even impossible for fundamental reasons. Investigations of various materials (TiO2, SnO2, ZnO) from single crystals to polycrystalline and quasi-amorphous thin films provided self-consistent data, highlighting various general issues as well. Examples include: (i) Determination of flatband potentials and donor concentrations by Mott-Schottky plots, particularly for nanotextured materials. There is a significant spread of experimental values, and unrealistically large concentrations of majority charge carriers, which could even wrongly predict degenerated semiconductors; (ii) Calculation of work functions and band edges by DFT, ignoring the influence of sample environment and/or defects in real crystals; (iii) Measurement of work functions and band edges by a single experimental technique, e.g., by photoelectron spectroscopy (UPS, NAP-UPS), Kelvin probe (KP), or electrochemistry (EIS), disregarding the inherent non-reproducibility of values from individual techniques; (iv) Transposition of these problematic data, both theoretical and experimental, into photocatalysis, photovoltaics, and solar fuel generation; (v) Application of the Gärtner-Butler model for carrier dynamics, disregarding the gradient of electrochemical potentials as the principal driving force for the exciton dissociation.
Join Zoom Meeting
https://cesnet.zoom.us/j/92741141335
Meeting ID: 927 4114 1335
---
One tap mobile
+420538890161,,92741141335# Czech Republic
+420228882388,,92741141335# Czech Republic
---
Dial by your location
• +420 5 3889 0161 Czech Republic
• +420 2 2888 2388 Czech Republic
• +420 2 3901 8272 Czech Republic
Meeting ID: 927 4114 1335
Find your local number: https://cesnet.zoom.us/u/abSqgdgQt7