Comparative Study of the Influence of Photoluminescence Quantum Yield and Molecular Orientation of Wide-Energy-Gap Small Molecules on the Performance of Organic Schottky Junctions

In this paper, we comparatively investigate the influence of absolute photoluminescence quantum yield (PLQY) and molecular orientation of a series of wide-energy-gap donors, which are usually used in organic light-emitting diodes, on the performance of organic Schottky junctions (OSJs) with low donor concentration. This work shows that PLQY of donors plays a crucial role on the photocurrent and fill factor of these types of OSJs. The PLQY of donors demonstrates a negative effect on the short-circuit current (J
_SC
) of OSJs. The molecular orientation of donors also influences the OSJ performance for both linearor planar-shaped molecules, and horizontal orientation helps to achieve a higher J
_SC
. The influencing priority of molecule characteristics of donors is PLQY>orientation.