Understanding and control of photon-induced dynamics of molecules on solid surfaces, including atomic rearrangements as well as charge transfer and non-equilibrium electron dynamics, are of essential importance for surface chemistry but also for the development of new devices. We use time-resolved momentum microscopy at a free-electron laser (FEL) and extend orbital tomography to time-resolved imaging of electronic wave functions of excited molecular orbitals. This technique will provide unprecedented insight into the ultrafast interplay between structural and electronic dynamics. In this work we prove general applicability and establish the experimental conditions at FEL sources to minimize space charge effects and radiation damage. We investigate a bilayer pentacene film on Ag(110) by optical laser pump and FEL probe experiments. From the momentum microscopy signal, we obtain time-dependent momentum maps of the molecular valence states that can be related to the molecular initial states by simulations of the involved photoemission matrix elements. A state above the Fermi level is identified which is temporarily occupied after optical excitation.

Function is dynamic and originates at atomic interfaces. Combining the degrees of freedom of molecules (1,2) with the peculiar properties of 2D quantum materials (3,4,5) can create novel functionality (6,7). Here, we report the manipulation and ultrafast imaging of a unidirectional gearing motion in molecules on a 2D quantum material. To visualize and disentangle the intertwined structural and electronic dynamics of such a hybrid interface, we record a ‘full molecular movie’ (8) by imaging the atomic positions (9,10), the evolution of the molecular orbital wavefunctions (11,12) and the modification of electronic states of the substrate (13). In a multimodal investigation in a single setup (14), we disentangle dynamics in valence and core electrons of both the molecule and the surface with femtosecond and sub-ångström precision. The ultrafast rotational motion is fueled by the transfer of hot holes into the molecules that results in “supercharging” of the film. As hot carriers move through the interface, we track a transient modification of the frontier molecular orbitals and observe a chiral symmetry breaking associated with local structural rearrangements. Our calculations show that the “supercharging” changes the interfacial potential energy landscape and triggers the gearing motion. The experiment offers all-in-one imaging of the electronic, molecular orbital, chemical and structural dynamics during the flow of charge and energy across the hybrid interface. Our approach provides detailed dynamical information on the mechanism underlying surface-adsorbed molecular gears and enables tailoring novel functionalities in hybrid active matter.