# Solution-Processed Thin Film of a Novel Organic Charge-Transfer Complex for Near-Infrared Detection in Field-Effect Transistors

## TL;DR

Researchers developed a new organic charge-transfer complex that can be processed into thin films for near-infrared detection in field-effect transistors.

## Contribution

A novel solution-processed thin film of a charge-transfer complex with scalable fabrication and near-infrared detection capabilities is demonstrated.

## Key findings

- The cocrystal (Ph-BTBT-C10)(F4TCNQ) was synthesized with a charge transfer degree of 0.19.
- The thin films showed n-type semiconducting behavior and a strong response to 1050 nm infrared light.
- The solution-shearing technique enabled low-cost, scalable fabrication of the CTC thin films.

## Abstract

Charge-transfer complexes (CTCs) have garnered considerable
attention
owing to their tunable electronic properties, which arise from the
unique interactions between electron donor and acceptor molecules.
However, reported fabrication methods remain largely restricted to
single crystals produced via drop-casting and coevaporation or thin
films prepared by cosublimation, thereby limiting their practical
applicability. In this work, we successfully synthesized cocrystals
of (Ph-BTBT-C10)­(F4TCNQ) with a charge transfer
degree (ρ) of 0.19. More importantly, we demonstrated the deposition
of these cocrystals as thin films in organic field-effect transistors
(OFETs) using a low-cost, rapid, and scalable solution-shearing technique
compatible with large-area fabrication. The resulting CTC thin films
exhibited n-type semiconducting behavior and showed a pronounced response
to infrared light at 1050 nm. The combination of a single-component
active layer whose near-infrared (NIR) absorption band can be chemically
tuned through donor–acceptor engineering with a scalable solution-based
processing method highlights the promise of CTC-based OFETs for advanced
IR detection and sensing applications. These results open new perspectives
for the technological exploitation of CTCs, a class of materials long
studied but rarely integrated into practical devices.