Enhancing Near‐Infrared Detection in Organic Phototransistors Using DBTTF‐TCNQ Cocrystal Engineering

Abstract Near‐infrared (NIR) organic phototransistors hold significant promise for a wide range of applications, but the availability of high NIR responses remains limited. In this study, a novel cocrystal strategy is presented, where dibenzotetrathiafulvalene (DBTTF) and 7,7,8,8‐tetracyanoquinodimethane (TCNQ) are selected as donor and acceptor, respectively, forming a charge transfer (CT) cocrystal through noncovalent interactions. The results show the cocrystal exhibits excellent light absorption in the NIR region, owing to strong CT interactions. Phototransistors based on these cocrystals exhibit a high photoresponsivity of 1000 mA W ⁻¹ at 980 nm, with a specific detectivity of 1.07 × 10 ¹¹ Jones, alongside a rapid response time of ≈2 ms. These superior characteristics are primarily due to the abundant D‐A interfaces, which facilitate efficient charge transfer. Moreover, the cocrystal shows impressive photodetectivity at an infrared range of 1550 nm, with a fast response time of just 1 ms. Furthermore, the device displays significant polarization dependence, with dichroic ratios of 1.47 at 850 nm and 2.33 at 980 nm, indicating its potential for advanced polarization imaging applications. This study demonstrates the effectiveness of cocrystal engineering in the development of high‐performance organic optoelectronic materials, offering a promising approach for next‐generation NIR photodetectors.