Tuning Absorption State and Intermolecular Potential of Organic Semiconductors for Narrowband Ultraviolet Photodetection

Abstract

AbstractNarrowband response of organic semiconductors determines the band selectivity and anti‐interference of the organic photodetectors, which are pursued for a long time but have not yet been resolved in the UV band. Herein, a feasible strategy is developed to realize narrowband UV response by tuning the absorption state and intermolecular potential of organic semiconductors. The as‐designed non‐Donor‐Acceptor molecule, 2,5‐diphenylthieno[3,2‐b]thiophene (2,5‐DPTT), exhibits narrowband absorption by fully suppressing the charge transfer state absorption. Simultaneously, the intermolecular potential is significantly enhanced (to ≈90 KJ mol−1) by modulating the molecular planarity. Consequently, the UV photodetector based on 2,5‐DPTT achieves excellent narrowband response at 310 nm wavelength and a record‐breaking photosensitivity (P = 1.21 × 106) in the deep UV range. In the demonstration application of flame alarm, the flame detector based on 2,5‐DPTT single crystal exhibits excellent anti‐interference capability. This work provides the inspiration for designing narrowband responsive organic semiconductors and building up multifunctional optoelectronic devices.