PbI₂-TiO₂ Bulk Heterojunctions with Long-Range Ordering for X-ray Detectors

Area of Science:

• Materials Science
• Detector Physics
• Nanotechnology

Background:

• High-performance X-ray detectors typically rely on single crystals for superior electronic properties.
• Bulk heterojunctions (BHJs) are known for enhancing photogenerated exciton dissociation in photodetectors.

Purpose of the Study:

• To investigate combining single crystal and BHJ strategies for improved X-ray detection.
• To develop a novel X-ray detector with enhanced sensitivity and carrier dynamics.

Main Methods:

• Incorporation of titanium dioxide (TiO2) networks into lead iodide (PbI2) crystals to form interpenetrating type II BHJs.
• Fabrication of long-range ordered BHJs using a gel-growth method.
• Characterization of electronic properties and X-ray detection performance.

Main Results:

• The developed BHJs exhibit long-range ordering comparable to single crystals.
• Improved separation of photogenerated electrons and holes, reducing recombination.
• A 6.4-fold increase in the mobility-lifetime product and a 5.8-fold improvement in X-ray sensitivity compared to single crystals.

Conclusions:

• A new strategy for fabricating high-performance X-ray detectors using gel-grown crystals and BHJs is presented.
• This work establishes a platform for studying X-ray carrier behavior in ordered BHJs.
• The findings demonstrate the potential of combining crystalline order with BHJ properties for advanced detector applications.