CNT:TiO₂-Doped Spiro-MeOTAD/Selenium Foam Heterojunction for High-Stability Self-Powered Broadband Photodetector

Area of Science:

• Optoelectronics
• Materials Science
• Semiconductor Devices

Background:

• Photodetectors are essential for optoelectronics, but selenium (Se) suffers from high reflectivity, and Spiro-MeOTAD has stability issues.
• Developing stable and efficient photodetectors is crucial for advanced applications in information conversion and image storage.

Purpose of the Study:

• To create a stable and high-performance photodetector by enhancing Spiro-MeOTAD and combining it with selenium foam.
• To investigate the photovoltaic properties and stability of the novel Se-F/Spiro-MeOTAD-1 heterojunction photodetector.

Main Methods:

• Spiro-MeOTAD-1 was synthesized with optimized dopants (Zn(TFSI)2 and CNT:TiO2) for enhanced stability.
• A Se-F/Spiro-MeOTAD-1 heterojunction was fabricated by compositing selenium foam (Se-F) with the modified Spiro-MeOTAD-1.
• Photovoltaic performance, including responsivity, switching ratio, detectivity, and response time, was characterized under 0 V bias within the 350-800 nm range.

Main Results:

• The self-powered Se-F/Spiro-MeOTAD-1 photodetector exhibited a maximum responsivity of 108 mA W⁻¹, a switching ratio of 5 × 10³, and a specific detectivity of 2.96 × 10¹² Jones.
• The device demonstrated a response time of 20 ms/50 ms and maintained 76.3% of its initial light current after 70 bending cycles, indicating excellent flexibility and stability.
• The photodetector showed enhanced environmental stability, withstanding pretreatment at 140 °C for one month.

Conclusions:

• The developed Se-F/Spiro-MeOTAD-1 photodetector offers superior performance and enhanced stability compared to conventional devices.
• This study validates the use of Spiro-MeOTAD-1 in Se-based photodetectors, establishing a new approach for designing high-performance and stable optoelectronic devices.