A High-Performance Solution-Processed Organic Photodetector for Near-Infrared Sensing.

Huang, Jianfei; Lee, Jaewon; Vollbrecht, Joachim; Brus, Viktor V; Dixon, Alana L; Cao, David Xi; Zhu, Ziyue; Du, Zhifang et al. · Adv Mater · 2020

basic_science · Level V

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Abstract

Sensitive detection of near-infrared (NIR) light enables many important applications in both research and industry. Current organic photodetectors suffer from low NIR sensitivity typically due to early absorption cutoff, low responsivity, and/or large dark/noise current under bias. Herein, organic photodetectors based on a novel ultranarrow-bandgap nonfullerene acceptor, CO1-4Cl, are presented, showcasing a remarkable responsivity over 0.5 A W<sup>-1</sup> in the NIR spectral region (920-960 nm), which is the highest among organic photodiodes. By effectively delaying the onset of the space charge limited current and suppressing the shunt leakage current, the optimized devices show a large specific detectivity around 10<sup>12</sup> Jones for NIR spectral region up to 1010 nm, close to that of a commercial Si photodiode. The presented photodetectors can also be integrated in photoplethysmography for real-time heart-rate monitoring, suggesting its potential for practical applications.