| Abstract [eng] |
One of the most attractive display technologies is organic light emitting diodes (OLEDs). The main advantages of OLED screens over LCD screens are improved image quality due to better contrast, higher brightness, wider color range; lower energy consumption; a simpler design that allows you to create very thin, flexible and even transparent screens. The most important component of an OLED is a light emitting material, commonly referred to as an emitter. Since the beginning of OLED technology, three major generations of emitters have been distinguished. The first generation, called fluorescent emitters, can successfully utilize up to 25% of electrical excitation. Second-generation, phosphorescent, emitters can utilize 100% of the excitation, but due to the complex synthesis and precious metals, second-generation emitters are very expensive. A decade ago, third-generation emitters were introduced, and the process behind them was called Thermally Activated Delayed Fluorescence (TADF). Thanks to intelligent molecular synthesis, TADF emitters can utilize 100% of the excitation without requiring any expensive elements, so such emitters are cheap to produce and can be very efficient. Despite the enormous amount of research, third-generation emitters still face a key problem that hinders their deployment in devices: the lack of efficient and stable blue emitters. This dissertation delved into the problem of blue TADF emitters and aimed to create high-efficiency and low-efficiency roll-off OLEDs. The record-breaking blue third-generation OLED devices demonstrated during the dissertation were fabricated using vacuum thermal evaporation and solution processing technologies. |
