Enhanced near-infrared photoresponse of organic phototransistors based on single-component donor–acceptor conjugated polymer nanowires

Abstract

Single-component near-infrared phototransistors based on ambipolar organic semiconductor nanowires have been investigated and compared with their corresponding thin-film counterparts. The nanowire organic phototransistors (NW-OPTs) showed photocurrent/dark-current ratios and photoresponsivities as high as 1.3 × 10(4) and 440 mA W(-1) for the p-type channel, and 3.3 × 10(4) and 70 mA W(-1) for the n-type channel, respectively, upon near-infrared illumination with an intensity of 47.1 mW cm(-2). These were much higher values compared to their thin-film counterparts. The enhancement of the near-infrared photoresponse could be attributed to the larger trap density originating from the semiconductor/insulator interface and the semiconductor/air interface. The performance of NW-OPTs was demonstrated to open up new possibilities to improve the near-infrared photoresponse of single-component devices.

N‐Type 2D Organic Single Crystals for High‐Performance Organic Field‐Effect Transistors and Near‐Infrared Phototransistors

“…For instance, along the crystalline texture orientation after annealing treatment in Chen's work, BODIPY‐BF2 film‐based NIR OPTs showed remarkable photoresponsivity ( R ) of 1.14 × 10 4 A W −1 under an 850 nm laser, which is two orders of magnitude greater than the amorphous film . Qiu and co‐workers reported that the NIR photoresponsivity of PBIBDF‐TT transistors was enhanced by replacing the thin‐film with 1D nanowire (NW) structures . Nevertheless, few reports remain about the restriction of dark current in NIR OPTs, which would worsen the sensitivity, particularly in low bandgap semiconductors .…”

Ambipolar organic phototransistors based on 6,6′-dibromoindigo

“…Phototransistors based on ambipolar materials, which are single component systems that can function as both p-and n-type semiconductors, have also been demonstrated. [24][25][26][27] Single component, ambipolar transistors are cost-effective and boast several advantages including largearea applicability and simple fabrication. Despite their advantages, research on ambipolar material-based phototransistors is insufficient.…”

Charge Transport Behavior and Ultrasensitive Photoresponse Performance of Exfoliated F16CuPc Nanoflakes

“…When the gate bias is above the threshold (on‐state), the barrier becomes smaller, which facilitates the drift of photogenerated carriers thus gaining larger drain current (panel IV of Figure b). However, as the gate bias keeps increasing, the photocurrent gradually saturates and decreases slightly, which could be explained by the enhanced photoexcited carrier recombination at high carrier concentrations …”