Thermally activated delayed fluorescence (TADF) is a phenomenon where molecules can undergo intersystem crossing between singlet and triplet states, allowing for efficient harvesting of triplet excitons and conversion into light emission. This process offers a way to enhance the efficiency of organic light-emitting diodes (OLEDs) by improving the utilization of both singlet and triplet excitons. TADF materials are designed to have a small energy gap between the lowest singlet and triplet excited states, enabling efficient reverse intersystem crossing and emission of delayed fluorescence. These materials have shown promise for achieving high-efficiency, low-cost OLEDs for display and lighting applications.