Fig. 1: AuNP superlattice synthesis.

a Scheme of superlattice preparation. First, 100 µl of AuNP@PSSH (sample details in Table 1) in toluene are pipetted onto a liquid subphase (DEG), then the well is covered with a glass slip to slow down the evaporation of the toluene. Superlattice films typically form within 16–24 h. b Photograph of a formed superlattice, scalebar 1 cm. c, d TEM measurements at different magnifications of a monolayer area in superlattices formed from AuNP25@PSSH2k (c: scalebar 500 nm, d: scalebar 100 nm). The inset in c shows the FFT of the digital image. e Low magnification of the same crystalline monolayer area covering >0.01 mm² of the TEM grid (scalebar: 50 µm). The small darker gray area in the top right corner is a bilayer. f Bilayer with few defects formed from AuNP25@PSSH5k (scalebar 500 nm). The inset shows an extended bilayer area (scalebar 100 µm). g SEM measurements of a crystalline multilayer superlattice with 22–23 layers formed from AuNP35@PSSH12k (scalebar 2 µm).