Enhanced photoelectric performance of Bi2O2Se/CuInP2S6 heterojunction via ferroelectric polarization in two-dimensional CuInP2S6†

Two-dimensional (2D) materials have drawn tremendous interest as promising materials for photoelectric devices due to their extraordinary properties. As an outstanding 2D photoelectric material, Bi₂O₂Se (BOS) has exhibited good performance and great potential in photoelectric applications. In this report, we have constructed a photoelectric heterojunction based on BOS and CuInP₂S₆ (CIPS) nanosheets to achieve enhanced photoelectric performance. With modulation of the ferroelectric-polarization-induced built-in electric field in CIPS, the photogenerated carriers in BOS are effectively separated to form a stable current that is independent of the applied voltage, so that the photoelectric performance of the heterojunction is significantly improved. The photoresponsivity (R), external quantum efficiency (EQE), and normalized detectivity (D*) are calculated and analyzed to evaluate the photodetection performance of the heterojunction. Results demonstrate excellent photoelectric performance of BOS/CIPS heterojunction under irradiation of light from ultraviolet (365 nm), visible (405/550/650 nm) to near-infrared (980 nm). R, EQE, and D* are up to 338.94 A W⁻¹, 7.65 × 10⁴%, and 3.99 × 10¹⁰ Jones, respectively, under the condition of 550 nm and 0.24 W m⁻². Meanwhile, the measured rise and fall times of the heterojunction reach 2.74 and 4.82 ms, respectively, indicating its fast photoelectric response. This work provides an effective approach to enhance the photoelectric response and stability of BOS via the ferroelectric-polarization-induced built-in electric field of CIPS.