Integrating self-assembled supramolecular organic frameworks with inorganic semiconductors for infrared photodetection

The surface coverage of two-dimensional (2D) materials has been a challenge, requiring facile growth of conformal 2D materials as well as considerations for transparency, energy level, and interface contact. Self-assembly holds promise for addressing this challenge by constructing precisely structured 2D assemblies using intentionally designed building blocks, guided by diverse noncovalent interactions. In this study, we utilize a self-assembled 2D supramolecular organic framework (SOF) to cloak inorganic semiconductors and form composite materials for infrared photodetection. The charged SOF backbone regulates the energy levels, facilitating the migration of electrons at the organic-inorganic interface. Additionally, the oxygen (O) of the ethylene glycol chains forms coordination bonds with the Pb(II) in the inorganic semiconductor, establishing ohmic contacts. The composite device shows excellent detectivity under 500 K blackbody and 1550 nm infrared illumination, achieving D*_bb(500 K) of 6.3 × 10⁹ Jones under 500 K blackbody radiation. Moreover, the device exhibits low noise due to the SOF potential barrier impeding the photogenerated and/or thermally excited holes, and high stability as a result of bonding and passivation of vacancy defects. This study showcases the versatile functionality of 2D SOF materials in the field of optoelectronics, opening doors to innovative advancements in composite devices through a self-assembled organic–inorganic approach.