The adsorption, self-organization and oriented attachment of PbSe nanocrystals (NCs) at liquid-air interfaces has led to remarkable nanocrystal superlattices with atomic order and a superimposed nanoscale geometry. Earlier studies examined the NC self-organization at the suspension/air interface with time-resolved in-situ X-ray scattering. Upon continuous evaporation of the solvent, the NC interfacial layer will finally contact the (ethylene glycol) liquid substrate on which the suspension was casted. In order to obtain structural information on the NC organization at this stage of the process, we examined the ethylene glycol/NC interface in detail for PbSe NCs of different sizes, combining in-situ grazing-incidence smalland-wide-angle X-ray scattering (GISAXS/GIWAXS), X-ray reflectivity (XRR) and analytical calculations of the adsorption geometry of these NCs. Here, we observe in-situ three characteristic adsorption geometries varying with the NC size. Based on the experimental evidence and simulations, we reveal fully three-dimensional arrangements of PbSe nanocrystals at the ethylene glycol-air interface with and without the presence of rest amounts of toluene.

Antiferromagnetic (AFM) FePS3 has gained significant interest recently for its potential applications in spin-related devices. This study exposes, for the first time, the strong impact of lateral crystal distortion on the magnetic arrangement and optical properties of FePS3. X-ray diffraction measurements uncovered a local anisotropy along the a/b crystallographic plane, inducing a breakage in FePS3 inversion symmetry, which greatly impacts it’s electronic and optical transitions. This includes an unexpected band-edge circularly polarized recombination emission, exposing a splitting of states in degenerate symmetric points (K+/K-). Secondly, implementation of crystal anisotropy in spin-exchange interactions among Fe atom’s nearest neighbors revealed stabilized a zigzag-AFM arrangement tilted away from the a-axis. Also, temperature-dependent PL measurements reflect arrangement at low temperatures and the coexistence of zigzag or Neél at mid temperatures. Highlighting the importance of the inclusion of a crystallographic anisotropy parameter for the simulation of the experimental observations.

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