High Polarization-Sensitivity Cs₂AgBiBr₆ Lead-Free Perovskite Vertically-Architected Field-Effect Phototransistors...

Polarization‑sensitive photodetectors (PDs), capable of accurately extracting objective information from complicated background noise, face great challenges for the burgeoning requirement combining anisotropic response and low‑energy consumption in shimmer marine environments. Here, we demonstrate the Cs₂AgBiBr₆ lead-free perovskite vertically-architected field-effect polarized phototransistors with a buffer layer of Mxene (Ti₃C₂T_x) nanosheets. Different from classical nanoimprint lithography, the depth-to-width ratio of Cs₂AgBiBr₆ stripe arrays is facilely engineered through the oxygen plasma bombardment, and optoelectronic performance and polarization sensitivity can be correspondingly balanced depending on the topological evolution. In the light of simulation, the localized relative-potential distribution of MXene suggests the intensified modulation effect for carrier transportation in comparison with Au nanostructures, and the noise current can be concurrently inhibited with the formation of the Schottky barrier between Cs₂AgBiBr₆ and MXene nanosheets. The strong dependence on the rectifying characteristic is observed with a variation of MXene concentrations, implementing an outstanding SS of ∼80 mV/dec at 2 mg/mL. Thus, the responsivity and anisotropic ratio radically increase by ∼1.43 and ∼1.80 times than those of the photoconductive PD, and the polarization sensitivity is confirmed with under-water imaging depending on polarization angles, providing a novel perspective for realizing low-noise under-water imaging.