RESUMO
The use of layered perovskites is an important strategy to improve the stability of hybrid perovskite materials and their optoelectronic devices. However, tailoring their properties requires accurate structure determination at the atomic scale, which is a challenge for conventional diffraction-based techniques. We demonstrate the use of nuclear magnetic resonance (NMR) crystallography in determining the structure of layered hybrid perovskites for a mixed-spacer model composed of 2-phenylethylammonium (PEA+) and 2-(perfluorophenyl)ethylammonium (FEA+) moieties, revealing nanoscale phase segregation. Moreover, we illustrate the application of this structure in perovskite solar cells with power conversion efficiencies that exceed 21%, accompanied by enhanced operational stability.
RESUMO
The self-assembly of highly functionalized phenanthrene-DNA conjugates into supramolecular nanostructures is presented. DNA oligomers modified with phenanthrene residues at the 3'-end and internal positions self-assemble into spherical nanostructures. The nanospheres exhibit light-harvesting properties. Upon irradiation of phenanthrene, the excitation energy is transferred along phenanthrene units, resulting in phenanthrene-pyrene exciplex formation.