Organometallic Dyes Modification on the NiOx Hole Transport Layer for Organic Photovoltaic Application

Nickel oxide (NiO
x
) has proved as an efficient hole transport layer (HTL) for perovskite solar cells (PSCs) with inverted structure. However, NiO
x
is rarely adopted as HTL for standard structure organic photovoltaics (OPVs) with PEDOT:PSS still widely used despite their drawbacks that could affect the device's operational stability. Passivation of NiO
x
/perovskite interface with self-assembled monolayer or organometallic dye could increase the performance of single junction inverted PSCs by suppressing defect densities at the interface of NiO
x
. However, their application in OPVs has not been explored. This work investigates the effect of NiO
x
passivation with various organometallic dye molecules (N719, C106, N3, N749, Z907) for OPV application. Our results show that only NiO
x
-based devices modified with N3 exhibit an efficiency increase compared to those with pristine NiO
x
HTL. This work provides insights into the role of the energy alignment between the NiO
x
interface with the OPV's active layer.