| Abstract [eng] |
Currently, organic electronics is one of the most developing technologies of semiconductor devices. This direction is rapidly expanding due to the constant molecular engineering of novel organic compounds and advances in device technology. Currently, organic materials are used in organic light-emitting diodes (OLEDs), organic thin-film transistors, solar cells and sensors, due to its especial properties enabling low-cost manufacturing techniques. Despite the great breakthrough in the creation of novel molecular emitters and OLEDs, still there are some weaknesses. One of the widely-used emitters is phosphorescent, of which the blue ones, due to the specific structure, suffers from the low stability and insufficient lifetime. One of the candidates to replace them are blue fluorescent emitters with remarkably higher stability and lifetime. These optimised fluorescent emitters, especially those utilising triplet-triplet annihilation, has efficiencies comparable to those of phosphorescent OLEDs. Few years ago, a new class of molecular emitters was offered, where the thermal activation of triplet excitons are used for the reversible intersystem crossing, leading to 100% of internal quantum efficiency. Efficiency of those TADF OLEDs is the same as of phosphorescent ones, however with much higher lifetime. Despite this, the molecular structure of TADF emitters is quite complex and even small changes of molecular architecture leads to remarkable changes of optical properties. In this work, the optimization of optical, thin-film forming and charge transport properties of two types of molecular emitters, fluorescent and TADF, will be presented. |
