Direct-Laser-Writing Manipulating α/δ-FAPbI₃ Array Enables Low-Crosstalk Terahertz Sensing and Imaging

Terahertz (THz) sensing and imaging have received increasing interest due to their high penetration and nondestruction. The photothermal effect empowers efficient room-temperature detection of feeble THz photons without cryogenic cooling systems. Nevertheless, the inevitable transverse diffusion of phonons and charge carriers under a thermal gradient brings signal crosstalk among sensing units, hampering the realization of high-resolution THz imaging. Herein, FAPbI3 is selected to construct a terahertz sensing array with direct-laser-writing micromanipulating α/δ-FAPbI3. α-FAPbI3 possesses a sensitive THz response, while the strong electron–phonon coupling in δ-FAPbI3 greatly suppresses the thermal and electrical crosstalk. As a result, in the THz sensing array, the crosstalk of neighbor pixels decreases from −5.35 to −17.60 dB. Moreover, the THz sensing unit exhibits a responsivity (R) of 34.3 μA W1–, noise equivalent power of less than 5.3 × 10–10 W Hz–1/2, and specific detectivity (D*) of 1.4 × 107 Jones. The proof-of-concept imaging further confirms that our THz sensing array can significantly enhance resolution in imaging.