Science - USA (2022-04-08)

206 8 APRIL 2022¥VOL 376 ISSUE 6589 science.orgSCIENCE

0D – Point vacancy, Interstitial 1D – Screw Dislocation

2D - Surface

Grain Boundary

3D – Frozen- In Positions and Inclusions

ace

(111)

(110)

[111]

(112)

(111)

AB

CD

E

F

G

(112)

(112)

(100)

(111)

93

84

85

89

89

93

I

13¡

H

J

Fig. 3. Observation of defects, dislocations, and distortions in the 3D
nanoparticle superlattice.(A) Observed and reconstructed particle superlattice
and vacancy defect (blue). (B) Lattice model with tetrahedron cages, with vacancy
(blue) visible. (C) Unit cell distortion with nominal neighbors (green) and distorted cell
(yellow). (D) Model packing of sphere with tetrahedron, with extra tetrahedron cage
surrounding nanoparticle. (E) Observed screw dislocation, viewed from the [112]
perspective with red/blue overlay. Thea/3 [111] Frankel-type defect runs from left
to right in a right-handed curl; overlaid are model (111), (110), and (112) planes.
(F) View of reconstructed 2D surface defects with [111] direction indicated. (G) Left:

Imaging of frozen-in particle positions. Center and right: Inclusion viewed from

90° perspectives. Spheres represent 20-nm Au nanoparticles. (H) Cropped portion of

reconstructed superlattice grain boundary showing faceting along [111] and [100]

directions. Perspective views of the (100) and (111) planes are overlaid with open

circles corresponding to idealized lattice positions, with blue and red dots representing

the experimentally observed particle positions. (I) Orthonormal vectors for red grain

and blue grain. (J) Low-angle mismatch between lattices from two perspectives

alongside a model with the calculated angle between the grains. Spheres represent

20-nm Au nanoparticles.

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