Search Results
Characterization of a superconducting Pb photocathode in a superconducting rf photoinjector cavity
2013, Barday, R., Burrill, A., Jankowiak, A., Kamps, T., Knobloch, J., Kugeler, O., Matveenko, A., Neumann, A., Schmeißer, M., Völker, J., Kneisel, P., Nietubyc, R., Schubert, S., Smedley, J., Sekutowicz, J., Will, I.
Photocathodes are a limiting factor for the next generation of ultrahigh brightness photoinjectors. We studied the behavior of a superconducting Pb cathode in the cryogenic environment of a superconducting rf gun cavity to measure the quantum efficiency, its spatial distribution, and the work function. We will also discuss how the cathode surface contaminants modify the performance of the photocathode as well as the gun cavity and we discuss the possibilities to remove these contaminants.
Structure of Diethyl-Phosphonic Acid Anchoring Group Affects the Charge-Separated State on an Iridium(III) Complex Functionalized NiO Surface
2020, Wahyuono, Ruri Agung, Amthor, Sebastian, Müller, Carolin, Rau, Sven, Dietzek, Benjamin
Cyclometalated Iridium(III) complexes, i. e. [Ir(C N)2(dppz)][PF6], bearing either two or four -CH2PO(OH)2 anchoring groups (IrP2dppz or IrP4dppz) are explored as photosensitizers for p-type dye sensitized solar cell (DSSC). The synthetic route is described and the iridium(III) complexes are characterized with respect to their electrochemical and photophysical properties. The modified anchoring ligand geometry exploited in this work not only alters the electronic nature of the complex (that is by destabilizing the LUMO energetically) but more importantly improves the grafting ability of the complex towards the NiO surface. The photoinduced long-lived charge separated state (CSS) at the NiO|IrPxdppz interface is of a different nature comparing the two complexes. For IrP2dppz and IrP4dppz the electron density of the CSS dominantly resides on the dppz and the C N ligand, respectively. The stability of the CSS can be correlated to the solar cell performance in NiO-based p-DSSCs, which yield conversion efficiencies which are among the highest in the class of iridium(III) complexes developed for p-DSSCs. © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.