A simple yet general swelling-deswelling microencapsulation strategy has been developed to achieve well dispersed and intimately passivated crystalline organic-inorganic perovskites nanoparticles within polymer matrixes and results in a series of highly luminescent CH NH PbBr (MAPbBr )-polymer composite films with unprecedented water and thermal stabilities and superior color purity.

The molecular structure, photochemistry, and device physics of conjugated polymers have been investigated by single-molecule spectroscopy (SMS), using the unique ability of this technique to unravel complex spectra and dynamics. Surprisingly efficient and directional electronic energy funneling was observed for conjugated polymer molecules due to highly ordered conformations. Furthermore, recent studies on the SMS of conjugated polymers embedded in electronic devices demonstrate that SMS is a powerful tool for studying the photophysics and charge-transfer processes of conjugated polymers, giving new insights into the complex interactions among excited and charged species that exist in a device environment.

Scanning tunneling microscopy (STM) is applied to study organic monolayers, physisorbed at the liquid-graphite interface. Due to the very local nature of the probing, the structure of these adlayers has been imaged with very high detail. The high resolution allowed us to investigate the effect of molecular chirality on the monolayer formation and provided a unique way to study chemical reactions at the liquid-graphite interface. Making use of a fast scanning mode, dynamic processes in these adlayers have been visualized.

Organic-inorganic halide perovskite quantum dots (PQDs) constitute an attractive class of materials for many optoelectronic applications. However, their charge transport properties are inferior to materials like graphene. On the other hand, the charge generation efficiency of graphene is too low to be used in many optoelectronic applications. Here, we demonstrate the development of ultrathin phototransistors and photonic synapses using a graphene-PQD (G-PQD) superstructure prepared by growing PQDs directly from a graphene lattice. We show that the G-PQDs superstructure synchronizes efficient charge generation and transport on a single platform. G-PQD phototransistors exhibit excellent responsivity of 1.4 × 108 AW–1 and specific detectivity of 4.72 × 1015 Jones at 430 nm. Moreover, the light-assisted memory effect of these superstructures enables photonic synaptic behavior, where neuromorphic computing is demonstrated by facial recognition with the assistance of machine learning. We anticipate that the G-PQD superstructures will bolster new directions in the development of highly efficient optoelectronic devices.

The light-induced and tip-induced polymerization of two diacetylene derivatives has been investigated at the air/solid interface by scanning tunneling microscopy (STM). One molecule is an isophthalic acid derivative with one diacetylene group, while the other one, a terephthalic acid derivative, contains two diacetylene functions. The design of the molecules (symmetry, presence of alkyl chains and hydrogen bonding moieties) leads to the formation of highly ordered two-dimensional patterns where the diacetylene groups stack in an optimal fashion. Both diacetylene derivatives can be polymerized by UV light irradiation, and locally the polymerization can be initiated and controlled by the STM tip. In addition to the formation of one-dimensional organic structures, it was possible to create two-dimensional organic nanostructures.