Hydrogen-Bond-Mediated Solid Additives Enabling Enhanced Bi-Continuous Interpenetrating Network for 20.29% Efficiency...

Area of Science:

• Materials Science
• Organic Electronics
• Photovoltaics

Background:

• Layer-by-layer (LbL) processing enables precise vertical phase separation in organic solar cells (OSCs).
• Optimizing donor morphology for acceptor infiltration is crucial for high-performance OSCs.
• Solid additives can modulate thin-film morphology in organic electronic devices.

Purpose of the Study:

• To develop novel solid additives for optimizing donor layer morphology in LbL-processed OSCs.
• To investigate the effect of BQ and BBQ additives on the D18 donor layer in D18/L8-BO devices.
• To enhance exciton dissociation and charge transport through improved morphology.

Main Methods:

• Synthesis and characterization of BQ and BBQ solid additives with a D-A-D conjugated skeleton.
• Fabrication of D18/L8-BO organic solar cells using LbL processing with BQ additive.
• Morphological analysis of the donor layer to assess crystallinity, orientation, and network formation.
• Device performance testing to determine power conversion efficiency.

Main Results:

• BQ additive induced intramolecular hydrogen bonds, promoting a planar D18 structure with enhanced crystallinity and face-on orientation.
• This resulted in an optimized fibrillar network, creating a pseudo-bulk heterojunction with increased interfacial area.
• BQ-processed LbL-OSCs achieved a power conversion efficiency of 20.29%.
• The BBQ additive led to excessive phase separation, disrupting homogeneity and molecular packing.

Conclusions:

• Hydrogen-bond-mediated solid additives are effective in fine-tuning donor layer morphology for high-performance LbL-OSCs.
• BQ additive facilitates efficient exciton dissociation and charge transport, leading to significant efficiency gains.
• The study demonstrates a promising strategy for developing advanced organic solar cell materials and processing techniques.