Annealing-Insensitive, Alcohol-Processed MoO Hole Transport Layer for Universally Enabling High-Performance...

Area of Science:

• Materials Science
• Renewable Energy
• Nanotechnology

Background:

• Solution-processed molybdenum oxide (s-MoO) hole transport layers (HTLs) are crucial for organic solar cells (OSCs).
• Current s-MoO HTLs are typically limited to conventional OSC architectures and unsuitable for inverted configurations.
• A need exists for versatile HTLs that are compatible with both device types and processing methods.

Purpose of the Study:

• To develop an annealing-insensitive, alcohol-processed MoO HTL.
• To demonstrate the universal applicability of this HTL in both conventional and inverted OSCs.
• To achieve high power conversion efficiencies (PCEs) and excellent stability in OSCs using the novel HTL.

Main Methods:

• Synthesized MoO nanoparticles (<5 nm) via nonaqueous pyrolysis of MoO₂(acac)₂.
• Dispersed nanoparticles in alcohol for spin-coating uniform s-MoO HTLs.
• Fabricated conventional and inverted OSCs using PM6:Y6, PBDB-T:ITIC, and PM6:L8-BO active layers with the s-MoO HTL.
• Tested device performance and stability under various annealing conditions and aging tests.

Main Results:

• Achieved PCEs of 17.09% for conventional and 16.28% for inverted OSCs with PM6:Y6, outperforming PEDOT:PSS and evaporated MoO₃ (e-MoO₃) based devices.
• Demonstrated annealing insensitivity, with optimal performance between room temperature and 110 °C.
• Exhibited excellent ambient stability for unencapsulated inverted OSCs, comparable to e-MoO₃ devices.
• Attained high PCEs of 18.21% (conventional) and 17.12% (inverted) with the PM6:L8-BO active layer.

Conclusions:

• The developed annealing-insensitive, alcohol-processed MoO HTL is a universal and high-performance component for both conventional and inverted OSCs.
• This HTL offers a promising alternative to existing materials, enabling high efficiencies and improved processing.
• The findings suggest significant potential for flexible and large-scale production of OSCs.