Figure 3
Example of a high-quality fit to experimental data. The black dots are experimental SAXS data obtained for a binary lattice of nanoparticles, wherein 7.8 0.9 nm diameter CdTe quantum dots are combined with 9.1 0.2 nm diameter Au nanoparticles. The two particle types each have attached DNA chains that are complementary to a linker strand, which is subsequently introduced to induce particle aggregation into a superlattice. Nanoparticles are coated with a 7 base-pair (b.p.) flexible segment followed by a 15 b.p. complementary region. The linker has a 30 b.p. double-stranded region, between complementary ends, to regulate interparticle distance. The solid blue line is a fit to the data, using the formalism described in the main text [equations (34)–(37)] and allowing interparticle distance and disorder parameters to vary (the best fit has a = 39.0 nm, and nm−1, which implies a grain size ). The top panel shows the residual signal used in fitting. The inset shows the assembled structure: a simple cubic unit cell, with particle positions following a body-centered cubic arrangement where each quantum dot (purple) connects to eight Au nanoparticle neighbors (gold). |