Electrically\nSwitchable Bipolar Polarization-Sensitive\nPhotodetection Based on a Biaxial Ferroelectric Semiconductor

Controlling the optoelectronic properties of semiconductors\nby\nan electric field is crucial for modern electronics, information processing,\ncomputing devices, and optical communication. The electrically switchable\npolarization feature of ferroelectrics offers the potential for manipulating\nlight–matter interactions. Herein, we demonstrate the electrically\nswitchable bipolar polarization-sensitive photodetection in a biaxial\nferroelectric semiconductor (4,4-DFPD)<sub>2</sub>PbI<sub>4</sub> (4,4-DFPD\nis 4,4-difluoropiperidinium). By altering the polarization direction\nvia an electric field, we induce corresponding changes in the anisotropic\nphotoresponse, which is driven by the bulk photovoltaic effect. Based\non this phenomenon, we put forward an encrypted optical communication\nmodel defined by biaxial ferroelectrics and successfully implement\nthe encryption/decryption transmission process of SOS signals. This\nwork provides new insights into the electrical control of light–matter\ninteractions and multiaxial ferroelectric optoelectronic applications.