Enhancing Organic Photodetectors for Indoor Low-Light Applications—Material Design, Interface Engineering, and Novel Fabrication Techniques for Improved Performance and Stability

This study presents strategies to improve organic photodetector (OPD) performance under low-light conditions through material design, interface engineering, and novel fabrication techniques. We introduce LK-2, a novel non-fused ring electron acceptor with a -3.61 eV LUMO level. In ternary blend active layers, LK-2 enhances VOC to 0.84 V and suppresses dark current density to 2.77×10^-10 A cm^-2, resulting in a 15% increase in fill factor under low light intensities [1]. Interface optimization using heterocyclic 1,3-diazoles in PEDOT:PSS films improves OPD performance. Devices with 0.5 wt.% 1,3-diazole show a 30% increase in detectivity and maintain 90% of their PPG signal intensity after 315 days, with 25% enhanced performance at 6.5 klx [2]. Buffer-free interfaces demonstrate exceptional low-light performance, with devices showing 0.5 A/W responsivity and 5.2×10¹⁴ Jones detectivity at 700 lx, doubling PDINN-based device performance. Surface roughness is reduced by 40% [3]. A hydrophobic membrane filtration technique reduces PCE variation from 15% to 5%. Filtered devices show 30% wider linear dynamic range and improved PCE from 15.73% to 20.96% at 6.5 klx [4]. Acid-free PEDOT:PSS-based photodiodes with HDZ improve carrier mobility and enable cardiovascular diagnostics. This approach enhances noise suppression in single pixel-based organic photodiodes [5]. Micro-cavity control in near-infrared OPDs reduces dark current from 2.36×10-8 to 7.07×10-10 A cm^-2. Performance is optimized at 830 nm with 3.35×10¹³ Jones detectivity, suitable for health monitoring applications [6]. These advancements address critical OPD challenges, improving performance under low-light conditions for indoor and medical applications.

[1] ACS Photonics, 2024, Just Accepted
[2] Applied Surface Science, 2024, Just Accepted
[3] Organic Electronics, 2024, 128: 107024
[4] Journal of Materials Chemistry C, 2024, Just Accepted
[5] Advanced Functional Materials, 2024, 34(11): 2309271
[6] Journal of Materials Chemistry C, 2024, 12(9): 3261-3271