Fig. 1

Colloidal platelet with self-assembled azobenzene monolayers in a nematic liquid crystal. a polarizing optical micrograph obtained under red imaging light when the platelet is illuminated by linearly polarized blue light with P_e⊥n₀ (green double arrows). P_e is indicated by a blue double arrow and crossed polarizers of the microscope are shown using white double arrows. b, c corresponding schematics of n(r) (green lines) and orientations of trans-state azobenzene moieties (red rods) within the self-assembled monolayers b, in the plane parallel to cell substrates (xy plane) and c in the cell’s vertical cross-section (xz plane). Black filled hemi-circles at the vertices of platelet along n₀ depict the boojum defects. d Polarizing micrograph of the same particle as in a, but when it rotates under blue-light illumination with P_e || n₀. Scale bar is 5 µm. e, f Schematics of n(r) and azobenzene orientations in the plane of platelets e, and in the plane beneath it f, both marked in g; the circular yellow arrow shows handedness of rotation. g Three-dimensional schematic of the self-assembled molecular-colloidal light-driven motor between two confining glass plates, with the green rods represent LC molecule and the azobenzene molecules of self-assembled monolayers shown in red