1 research outputs found
Energy Level Tuning of Non-Fullerene Acceptors in Organic Solar Cells
The use of non-fullerene
acceptors in organic photovoltaic (OPV)
devices could lead to enhanced efficiencies due to increased open-circuit
voltage (<i>V</i><sub>OC</sub>) and improved absorption
of solar light. Here we systematically investigate planar heterojunction
devices comprising peripherally substituted subphthalocyanines as
acceptors and correlate the device performance with the heterojunction
energetics. As a result of a balance between <i>V</i><sub>OC</sub> and the photocurrent, tuning of the interface energy gap
is necessary to optimize the power conversion efficiency in these
devices. In addition, we explore the role of the charge transport
layers in the device architecture. It is found that non-fullerene
acceptors require adjusted buffer layers with aligned electron transport
levels to enable efficient charge extraction, while the insertion
of an exciton-blocking layer at the anode interface further boosts
photocurrent generation. These adjustments result in a planar-heterojunction
OPV device with an efficiency of 6.9% and a <i>V</i><sub>OC</sub> above 1 V