He received the award for his publication:
S. Kuhn, B.A. Stickler, A. Kosloff, F. Patolsky, K. Hornberger, M. Arndt, J. Millen, "Optically driven ultra-stable nanomechanical rotor", Nature Communications 8, 1670 (2017). DOI: 10.1038/s41467-017-01902-9