Recently, diboron based blue thermally activated delayed fluorescence (TADF) material, N7,N7,N13,N13,5,9,11,15-octaphenyl-5,9,11,15-tetrahydro-5,9,11,15-tetraaza-19b, 20b-diboradinaphtho[3,2,1-de:10,20,30-jk] pentacene-7,13-diamine (m-DABNA) has drawn attention from the researchers due to its gooddevice performances as well as narrow full-width at half maximum (FWHM) in OLED devices. In thiswork, we report a detailed analysis to understand the exact reason behind the efficiency variations inm-DABNA based TADF devices using different types of host materials. Interestingly, we found that tripletexciton density of m-DABNA molecule is mainly located at the central region, so the triplet exciton energytransfer from the host material is hindered due to the presence of peripheral diphenylamine extensions. Hence, our analysis suggests that utilizing wide band gap host materials in m-DABNA based TADF devicesexhibit excellent device efficiencies with the support of trap assisted emission mechanism. This studybrings an in-depth understanding of efficiency variations in the m-DABNA based OLED devices.