Improved Efficiency and Stability of Organic Solar Cells by Interface
Modification Using Atomic Layer Deposition of Ultrathin Aluminum Oxide
Abstract
The interfacial contacts between the electron transporting layers (ETLs)
and the photoactive layers are crucial to device performance and
stability for OSCs with inverted architecture. Herein, atomic layer
deposition (ALD) fabricated ultrathin Al2O3 layers are applied to modify
the ETLs/active blends (PM6:BTP-BO-4F) interfaces of OSCs, thus
improving device performance. The ALD-Al2O3 thin layers on ZnO
significantly improved its surface morphology, which led to the
decreased work function of ZnO and reduced recombination losses in
devices. The simultaneous increase in open-circuit voltage (),
short-circuit current density () and fill factor (FF) were achieved for
the OSCs incorporated with ALD-Al2O3 interlayers of a certain thickness,
which produced a maximum PCE of 16.61%. Moreover, the ALD-Al2O3
interlayers had significantly enhanced device stability by suppressing
degradation of the photoactive layers induced by the photocatalytic
activity of ZnO and passivating surface defects of ZnO that may play the
role of active sites for the adsorption of oxygen and moisture.