Acid-Amine Equilibria for Formation and Long-Range Self-Organization of Ultrathin CsPbBr Perovskite Platelets.

Impact of acid-amine equilibrium for triggering the formation of CsPbBr platelets and subsequent long-range self-assembly as a function of acid concentration is reported. The study was performed by treating Cs precursor followed by oleic acid to the ongoing process of LPbBr layered perovskites formation at room temperature, and this led to the thinnest possible platelets of CsPbBr with one atomic layer of Cs insertion. These platelets form self-assembly in the micrometer range, and this ordering was tuned as a function of oleic acid concentration and reaction time.

Electron transfer across the germanium-polyelectrolyte-gold nanoparticle interface: convenient detection and applications in sensing.

Germanium-polyelectrolyte-gold nanoparticle composites were prepared and characterized using FTIR-ATR spectroscopy and scanning electron microscopy. The germanium (Ge) element served as an internal reflection element and the buildup of the layered system was followed in situ. A positively charged polyelectrolyte, poly (allylamine hydrochloride) (PAH) adsorbs spontaneously on negatively charged Ge.

An IR modulator based on the self-assembly of gold nanoparticles on germanium.

By using a polyelectrolyte layer gold nanoparticles have been assembled onto a Ge internal reflection element. Upon illumination with visible and near infrared light strong infrared absorption has been observed, which can be traced to intervalence band transitions in Ge. This reveals the existence of holes in the Ge near its valence band edge.