Optimization and performance enhancement in PBDB-T:ITIC-based organic photodetector via SWCNT integration

The versatility of organic photodetectors (OPDs) is evident from their flexible structures and impressive performance metrics. These materials are positioned to transform optoelectronics by enabling the manufacturing of high-performance devices using cost-effective processes. This study explored the addition of single-walled carbon nanotubes (SWCNTs) to PBDB-T:ITIC-based OPDs using numerical analysis with SCAPS 1D software. The optimized modeled structure PFN:Br/SWCNT/PBDB-T:ITIC/Spiro-MeOTAD/Cu yielded a responsivity of 0.2308 A/W and a detectivity of 8.8 × 10¹³ Jones. The combination of SWCNTs with the PBDB-T:ITIC matrix significantly improved the short-circuit current density (Jsc) to 23.68 mA/cm² and open-circuit voltage (Voc) to 0.73 V. The structured OPD achieved a fill factor (FF) of 75.88% at a thickness of 200 nm for the photosensitive layer. The study also examined the impact of environmental factors, such as temperature and light intensity, and the effect of series and shunt resistance on the device output parameters. Optimal performance was observed under 1 sun illumination at room temperature (300 K), where a low series resistance (1 Ω cm²) and high shunt resistance (1000 Ω cm²) were crucial for achieving exceptional device metrics. The built-in potential (Vbi) and doping density (Nd), determined through C-V measurements, were 0.74 V and 3.24 × 10¹⁷ cm⁻³, respectively. The Nyquist plots of the optimized structure display a semicircular shape, indicating reduced recombination rates and enhanced efficiency. These findings highlight the potential of SWCNT integration for enhancing the performance and stability of OPDs, particularly in visible-range applications.