Printed SWCNT‐Based p–n Junction Thin‐Film Near‐Infrared Photoresistors Enabled by a Sustainable Furan‐Derived π‐Conjugated Polymer

Semiconducting single‐walled carbon nanotubes (SWCNTs) are attractive for near‐infrared (NIR) sensing but suffer from weak photocurrent due to large exciton binding energies. Here, we pair chirality‐enriched (10,9)‐ SWCNT as the electron acceptor with a sustainable, furfural‐derived π‐conjugated polymer ( PFEB ) as the electron donor to fabricate lateral, resistor‐type p‐n heterojunction NIR photodetectors to facilitate exciton dissociation. Post‐deposition thermal cleavage of PFEB ’s carbamate side chains yields PFNB , which tightens polymer–nanotube contact and switches the dominant response of the sensors from ∼800 to ∼1000 nm. The optimized PFNB /(10,9)‐enriched SWCNT device on SiO 2 substrates achieves EQE = 19.7%, R = 0.159 A W −1 , and D * = 2.66 × 10 8 Jones at 1000 nm and 1.0 V, while an all‐printed device on a polyimide substrate reaches EQE = 6.47%, R = 0.0522 A W −1 , and D * = 7.90 × 10 7 Jones. Photoluminescence‐excitation quenching (∼78%) and redshifts/broadening in (10,9)‐enriched SWCNT optical bands evidence strong interfacial coupling and interfacial charge transfer. The devices require neither transparent electrodes nor complex stacks, and they are fabricated via ultrasonic micro‐printing using picoliter ink volumes. This work demonstrates a scalable route to high‐performance, low‐power, and environmentally friendly NIR sensing.