Design and synthesis of a conjugated polymer for an organic photodetector

초록

Organic photodetectors (OPDs) have emerged as promising alternatives to inorganic photodetectors because of their low-cost fabrication, lightweight, ease of processing, mechanical flexibility, and tailorable optical properties. Herein, a new donor polymer based on a naphtho[2,1-b:3,4-b’]dithiophene (NDT) backbone, which is a rigid, planar, symmetric, and electron-rich π-conjugated framework, was synthesized for green-selective OPDs. The polymer exhibited strong absorption at ~ 535 nm and suitable optoelectronic properties for device fabrication. Bulk heterojunction OPDs were fabricated using PNDT and PCBM blend ratios of 1:1, 1:2, and 1:4, with different donor-to-acceptor weight ratios. Device performance strongly depended on the PNDT: PCBM blend ratio. Increasing the PCBM content enhanced photocurrent generation, whereas excessive PCBM also increased the reverse dark current. Consequently, the 1:1 blend exhibited the highest specific detectivity owing to its suppressed dark current with moderate photocurrent. These results highlight PNDT as a promising active material for high-performance green-selective organic photodetectors. © The Author(s), under exclusive licence to The Polymer Society of Korea 2026.

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