The targeted design of lanthanide-based emitters for solution-processed organic light-emitting diodes (OLEDs) resulted in obtaining an NIR OLED with one of the highest efficiencies among ytterbium-based solution-processed OLEDs (30 μW W⁻¹). The design was aimed at the combination of high luminescence efficiency with solubility and charge carrier mobility. The latter was achieved thanks to the introduction of the purposefully selected neutral ligands, which combine electron mobility and the ability to sensitize lanthanide luminescence. Besides, the HOMO and LUMO energies and charge carrier mobility of solution-processed thin films of coordination compounds were measured experimentally for the first time, and novel highly luminescent europium-based materials with PLQYs of up to 80% and purely NIR luminescent ytterbium complexes were obtained.

A novel strategy is presented towards acquisition of exciplex systems exhibiting thermally activated delayed fluorescence (TADF) with a high reverse intersystem crossing (RISC) rate (exceeding 10⁷ s⁻¹). This approach involves constructing exciplex donor–acceptor molecular pairs, where the acceptor molecule possesses the ability to undergo fast and efficient intersystem crossing (ISC). With the use of 6-cyano-9-phenylpurine (PCP) acceptor and carbazole-based donor molecules, exciplexes were obtained, where the excitation is contained on PCP and undergoes fast ISC to form a local excited triplet state (³LE_A). The controlled excitation transfer to the ³LE_A level provides an optimal reverse intersystem crossing pathway, enabling TADF with a sub-microsecond emission lifetime. The side-effect of such an emissive mechanism is an unusual thermal photoluminescence quenching, caused by the limited PCP triplet state stability under room temperature conditions. PCP-carbazole dyads were obtained, which, in neat solid films, form intermolecular TADF-active exciplexes between donor and acceptor fragments of the neighbouring molecules. These compounds show balanced bipolar charge transport ability and were used as emissive layer host materials. The obtained organic light emitting diode (OLED) with an exciplex-forming host and a TADF emitter showed an external quantum efficiency exceeding 10% and low efficiency roll-off.

Ultrathin ZnO interlayer boosts TiO ₂ –based Sb ₂ S ₃ solar cells to record efficiencies 7.5% AM 1.5G and 18% indoor. Reduced nonradiative losses, passivated front interface, and larger Sb ₂ S ₃ grains enable stable power for IoT applications.

The deposition of Bi₂O₃ thin films and the photocatalytic efficiency of the obtained films.