File Name : fig.s1.png

Caption : figure s1. the tem images of au nc. (a) tem image of the ctab layer coating the au nc surface. (b) the hrtem image of au nc with the (111) plane.

File Name : fig s2.png

Caption : figure s2 the comparative experiments of particle motions. (a) a time series of tem images showing the dynamic motion of 20 nm and 30 nm nc. electron beam dose: 5.2 e-/(å2·s). images with gaussian blur filter, σ=1 pix. (b) a time series of tem images showing pure citrate au nps attaching on the sinx substrate. electron beam dose: 5.5 e-/(å2·s). images with gaussian blur filter, σ=1.5 pixs. (c) the schematic diagram of cta+ inserted into the gap of citrate au and the positive charge substrate to shield their electrostatic attraction. (d) a time series of tem images showing the ctab nc and citrate np self-assembly motions in high ctab concentration (~40 mm). notes that the citrate au twins formation indicating the repulsion force among citrate au nps decreasing. electron beam dose: 6.0 e-/(å2·s).

File Name : fig s3.png

Caption : figure s3 a time series of tme images show the np keeps jumping and moves away from the au nc without attachment. electron beam dose: 4.1 e-/(å2·s).