Thermally activated delayed fluorescence (TADF) materials have been regarded as promising host materials for fluorescent and phosphorescent guest materials to achieve high performance organic light-emitting diodes (OLEDs). In this work, three molecules, PhCQ, m-PyCQ and p-PyCQ, using carbazole derivatives as donor and quinazoline units as acceptor were designed and synthesized. Both theoretical and experimental results showed that PhCQ, m-PyCQ and p-PyCQ possess TADF properties with higher triplet excited states than red phosphorescent guest, RD-1. When used as host materials for RD-1, it was found that the emission spectrum of PhCQ has the largest overlap with the absorption spectrum of RD-1, which is conducive to Förster resonance energy transfer (FRET) between the host to the guest. As a result, red phosphorescent OLED device based on PhCQ host exhibited the best performances with the maximum external quantum efficiency (EQE) of 37.2 %. When the brightness is 1000 cd/m2, the EQE is still as high as 33.0 %.