TY  - JOUR
A1  - von Reppert, Alexander
A1  - Sarhan, Radwan Mohamed
A1  - Stete, Felix
A1  - Pudell, Jan-Etienne
A1  - Del Fatti, N.
A1  - Crut, A.
A1  - Koetz, Joachim
A1  - Liebig, Ferenc
A1  - Prietzel, Claudia Christina
A1  - Bargheer, Matias
T1  - Watching the Vibration and Cooling of Ultrathin Gold Nanotriangles by Ultrafast X-ray Diffraction
JF  - The journal of physical chemistry : C, Nanomaterials and interfaces
N2  - We study the vibrations of ultrathin gold nanotriangles upon optical excitation of the electron gas by ultrafast X-ray diffraction. We quantitatively measure the strain evolution in these highly asymmetric nano-objects, providing a direct estimation of the amplitude and phase of the excited vibrational motion. The maximal strain value is well reproduced by calculations addressing pump absorption by the nanotriangles and their resulting thermal expansion. The amplitude and phase of the out-of-plane vibration mode with 3.6 ps period dominating the observed oscillations are related to two distinct excitation mechanisms. Electronic and phonon pressures impose stresses with different time dependences. The nanosecond relaxation of the expansion yields a direct temperature sensing of the nano-object. The presence of a thin organic molecular layer at the nanotriangle/substrate interfaces drastically reduces the thermal conductance to the substrate.
Y1  - 2016
U6  - https://doi.org/10.1021/acs.jpcc.6b11651
SN  - 1932-7447
VL  - 120
SP  - 28894
EP  - 28899
PB  - American Chemical Society
CY  - Washington
ER  -