Exploring Deep and Shallow Trap States in a Non-Fullerene Acceptor ITIC Based Organic Bulk Heterojunction Photovoltaic System

Nonfullerene organic molecules that usually act as acceptors have exhibited prominent optoelectronic properties in organic bulk heterojunction (BHJ) solar cells. Although the highly efficient exciton dissociation can happen even with a relatively smaller driving force, the underlying energy loss including exciton dissociation and electron–hole recombination in the nonfullerene acceptor (NFA) system remains unclear. In principle, the energetic disorder characteristic is a common feature in organic semiconductors as well as their organic blends due to the molecular random distribution and the donor–acceptor interpenetration network. Owing to their completely different molecular structures in contrast to the bulky-ball shaped fullerene-derivative counterpart such as PCBM, a comprehensive understanding for the trap-associated energetic disorder characteristic and distribution are merits to further eliminate the open-circuit voltage (Voc) loss. In this work, a highly efficient planar organic BHJ solar cell com...