Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 27: Zinc Oxide and Zinc Selenide

HL 27.9: Vortrag

Dienstag, 8. März 2016, 12:00–12:15, H17

Electron-hole recombination dynamics in CdS nanocrystals: limiting steps of photocatalytic H2 generation — •Thomas Simon, Michael Carlson, Jacek Stolarczyk, and Jochen Feldmann — Chair for Photonics and Optoelectronics Ludwig-Maximilians-Universität, Amalienstr. 54, 80799 Munich, Germany

Semiconductors functionalized with additional noble metal clusters are well-known materials for photocatalytic fuel generation. The generation of elemental hydrogen from aqueous solution with cadmium sulfide nanorods decorated with platinum particles is of particular interest. Here the photoexcited electron is efficiently transfered from the semiconductor to the metal where it in turn reduces water molecules to elemental hydrogen. However, the photohole is not able to oxidize the water molecules but has to be removed by a sacrificial reducing agent to prevent the crystal from oxidation [1]. We studied the relaxation and recombination pathways of photoexcited carriers by femtosecond transient absorption spectroscopy. We found that a non-perfect or unstable charge separation finally leads to enhanced electron-hole recombination diminishing the photocatalytic quantum yield. Proper deposition techniques of the co-catalyst particles can bypass this problem.

[1] T. Simon, N. Bouchonville, M.J. Berr, A. Vaneski, A. Adrović, D. Volbers, R. Wyrwich, M. Döblinger, A.S. Susha, A.L. Rogach, F. Jäckel, J.K. Stolarczyk and J. Feldmann Nat. Mat. 13, 1013-1018 (2014)