Our research group is currently conducting basic research on organic light-emitting diodes (OLEDs). Recently, we have successfully developed a series of blue and green TADF emitters for OLEDs realizing high external quantum efficiencies through high-throughput screening based on quantum chemical calculations. However, even using highly efficient emitting materials, the device performance depends on the device structure and aggregated state of organic molecules in the device. To understand the origin of the device performance, both theoretical and experimental approaches are important. In this regards, we have also carried out multiscale simulations and solid-state NMR (ssNMR) analysis of organic amorphous thin films. The ssNMR is the powerful technique for the detailed experimental analysis of amorphous aggregated materials, which has been difficult by typical diffraction methods because organic molecules in OLEDs are in the amorphous state. However, the low sensitivity of ssNMR compared to other analytical methods has always been a crucial problem. Recently, dynamic nuclear polarization enhanced ssNMR (DNP-ssNMR) has become popular for the sensitivity enhancement technique for ssNMR. In this presentation, we show the analysis of molecular orientation of an organic semiconducting material in an amorphous thin film state using DNP-ssNMR.