1 Increased superconducting transition temperature of a niobium thin-film proximity-coupled to gold nanoparticles using linking organic molecules Eran Katzir, 1 Shira Yochelis, 1 Felix Zeides, 2 Nadav Katz, 2 Yoav Kalcheim, 2 Oded Millo, 2 Gregory Leitus, 3 Yuri Myasodeyov, 4 Boris Ya. Shapiro, 5 Ron Naaman, 6 and Yossi Paltiel 1 1 Applied Physics Department and the Center for Nano-Science and Nano-Technology, the Hebrew University of Jerusalem, Jerusalem, 91904 Israel. 2 Racah Institute of Physics the Hebrew University of Jerusalem, Jerusalem, 91904 Israel 3 Chemical Support, The Weizmann Institute, Rehovot 76100, Israel 4 Department of Physics, The Weizmann Institute of Science, Rehovot, 76100 Israel. 5 Physics Department, Bar-Ilan University, Ramat-Gan, 52900 Israel 6 Department of Chemical Physics, The Weizmann Institute of Science, Rehovot, 76100 Israel. Corresponding author: Yossi Paltiel- paltiel@cc.huji.ac.il Abstract: The superconducting critical temperature, T C , of thin Nb films is significantly modified when gold nanoparticles (NPs) are chemically linked to the Nb film, with a consistent enhancement when using 3 nm long disilane linker molecules. The T C increases by up to 10% for certain linker length and NPs size. No change is observed when the nanoparticles are physisorbed with non-linking molecules. Electron tunneling spectra acquired on the linked NPs below T C typically exhibit zero-bias peaks. We attribute these results to a pairing mechanism coupling electrons in the Nb and the NPs, mediated by the organic linkers.