Optoelectronic Property Modulation in Chiral Organic Semiconductor/Polymer Blends

Area of Science:

• Organic electronics
• Materials science
• Optoelectronics

Background:

• Organic phototransistors (OPTs) are crucial for sensing, communication, and imaging.
• Charge-trapping enhances OPT photoresponsivity by reducing dark current.
• Combining chiral organic semiconductors with insulating polymers for optoelectronics is underexplored.

Purpose of the Study:

• To fabricate and evaluate organic phototransistors (OPTs) using chiral perylene diimide derivatives and polylactide (PLA).
• To investigate the impact of chiral composition on optoelectronic performance.
• To explore charge-trapping effects in PLA-blended OPTs.

Main Methods:

• Fabrication of OPTs with enantiopure and racemic n-type perylene diimide derivatives (CPDI-CN2-C6) blended with PLA.
• Evaluation of photoresponsive properties, electron mobility, and specific detectivity.
• Analysis of material morphology and grain structure.

Main Results:

• PLA-blended OPTs demonstrated significantly enhanced performance due to charge-trapping.
• The racemic system exhibited 3x higher electron mobility compared to enantiopure systems.
• The racemic system achieved 12x higher specific detectivity (1.3 × 10^13 jones).
• Racemic mixtures showed more aggregated morphologies and larger grains.

Conclusions:

• Chiral composition is a tunable parameter for optimizing optoelectronic devices.
• PLA blending is an effective strategy for creating high-performance n-type OPTs.
• The developed method offers a feasible route to high-performance OPTs under ambient conditions.