Ti-Oxo Clusters with Peripheral Alkyl Groups as Cathode Interlayers for Efficient Organic Solar Cells

Area of Science:

• Materials Science
• Organic Electronics
• Nanotechnology

Background:

• Organic solar cells (OSCs) require efficient cathode interlayers for optimal performance.
• Developing new materials with tailored electronic properties is crucial for advancing OSC technology.

Purpose of the Study:

• To synthesize and characterize novel titanium-oxo clusters (TOCs) for use as cathode interlayers in OSCs.
• To investigate the impact of TOCs on the performance and charge transport properties of OSCs.

Main Methods:

• Synthesis of three independent TOCs with varying Ti atom cores (6, 8, 12) and surface alkyl groups.
• Fabrication of bulk-heterojunction OSCs utilizing TOCs as cathode interlayers via spin-casting.
• Performance evaluation of OSCs, including power conversion efficiency (PCE) measurements.

Main Results:

• TOCs demonstrated precise chemical structures, good solubility, and well-aligned work functions.
• Smooth TOC films were easily formed, leading to a high PCE of 17.29% in OSCs.
• TOCs effectively reduced silver electrode work function and induced n-doping in non-fullerene acceptors, enhancing electron extraction and transport.

Conclusions:

• Titanium-oxo clusters show significant potential as high-performance semiconductor interlayers for OSCs.
• TOCs offer a promising strategy for improving energy level alignment and charge transport in organic electronic devices.