Characterization of Optical and Photoelectrical Properties of ZnO Crystals

We characterized optical and photoelectrical properties of undoped and Ga-doped ZnO layers differently grown on sapphire substrates by using complementary optical methods. Different stimulated emission threshold values for ZnO epitaxial layers grown by pulsed laser deposition and MBE methods were attributed to crystalline quality of the layers and the growth method used. Different carrier lifetimes in various ZnO epitaxial layers are explained by defect-related and intrinsic mechanisms of recombination

Purely organic thermally activated delayed fluorescence (TADF) materials for organic light-emitting diodes (OLEDs)

We thank the University of St Andrews for support. EZ-C thanks the Leverhulme Trust for financial support (RPG-2016-047). and the EPSRC (EP/P010482/1) for financial support.The design of thermally activated delayed fluorescence (TADF) materials both as emitters and as hosts is an exploding area of research. The replacement of phosphorescent metal complexes with inexpensive organic compounds in electroluminescent (EL) devices that demonstrate comparable performance metrics is paradigm shifting as these new materials offer the possibility of developing low-cost lighting and displays. Here we present a comprehensive review of TADF materials with a focus on linking their optoelectronic behavior with the performance of the organic light-emitting diode (OLED) and related EL devices. TADF emitters are cross-compared within specific color ranges, with a focus on blue, green-yellow,orange-red and white OLEDs. Organic small molecule, dendrimer, polymer and exciplex emitters are all discussed within this review, as is their use as host materials.Correlations are provided between the structure of the TADF materials and their optoelectronic properties. The success of TADF materials has ushered in the next generation of OLEDs.Publisher PDFPeer reviewe