Ferroelectricity‐Driven Self‐Powered Ultraviolet Photodetection with Strong Polarization Sensitivity in a Two‐Dimensional Halide Hybrid Perovskite

Abstract

Polarization-sensitive ultraviolet (UV) photodetection is highly indispensable in military and civilian applications and has been demonstrated with various wide-band photodetectors. However, it still remains elusive to achieve the selfpowered devices, which can be operated in the absence of external bias. Herein, for the first time, ferroelectricity-driven self-powered photodetection towards polarized UV light was successfully demonstrated in a 2D wide-band gap hybrid ferroelectric (BPA) 2 PbBr 4 (BPA = 3-bromopropylammonium) (1). We found that the prominent spontaneous polarization in 1 results in a bulk photovoltaic effect (BPVE) of 0.85 V, that independently drives photoexcited carriers separation and transport and thus supports self-powered ability. This self-powered detector shows strong polarization sensitivity to linearly polarized UV illumination with a polarization ratio up to 6.8, which is superior to that of previously reported UVpolarized photodetectors (ZnO, GaN, and GeS 2). Polarization-sensitive photodetectors have attracted extensive attention owing to their remarkable polarization dependent optoelectronic properties. [1-3] Among them, polarizationsensitive ultraviolet (UV) photodetection capable of detecting polarized UV light is a significant branch of optoelectronics and has been adapted to various fields, ranging from communication, near field imaging, remote sensing, as well as to military surveillance. [4-9] During the past decades, most attention on polarization-sensitive UV photodetection was devoted to conventional wide band gap semiconductor medium with nanowire geometry, such as GaN [4] and ZnO. [5] Recently, anisotropic 2D semiconductor GeS 2 also has been demonstrated to be potential building element for UVpolarized detection due to the intrinsic anisotropic crystal structure. [10] However, an external power source was usually required as driving force in all above mentioned devices to separate the photogenerated carriers, which not only consumed energy but also largely increased the system size and integrated cost. Self-powered photodetectors represent a new type of candidate without external energy supply, which can

Spacer Cation Alloying of a Homoconformational Carboxylate trans Isomer to Boost in-Plane Ferroelectricity in a 2D Hybrid Perovskite

“…The maximum photocurrent appears along the c axis (θ = 0°), where the polarized-light electric field is parallel to the in-plane component of ferroelectric P s . In contrast, the minimum photocurrent is observed along the b axis (θ = 90°), where the polarized-light direction is perpendicular to ferroelectric polarization . This result suggests a potential coupling between the electric field component of polarized light with that of P s , which will promote the dissociation of charge carriers and result in a large photocurrent.…”

High-Polarization-Sensitivity Polarimetric Organic Phototransistors Based on Highly Stretchable Semicrystalline Polymer Semiconductors

“…(f) Transient photocurrents of the P-OPTs obtained with polarized light at a frequency of 40 Hz (irradiance: 8.4 mW cm –2 ). (g) Polarized absorption coefficient values of stretched P2 thin film at various strains, (h) normalized transient photocurrents of the P-OPTs, and (i) τ r values of the P-OPTs obtained at θ = 0° (red) and 90° (blue). − …”

Recent Progress of Polarization‐Sensitive Perovskite Photodetectors

“…[91] The ratio of the maximum to minimum photocurrent along the two vertical polarization angles of the single crystal device is 1.31 at 450 nm. Photocurrent dichroic ratios are comparable to 1D CsCu2I3 nanowires (3.16 at 325 nm), [92] 1D CsPbBr 3 perovskite arrays (2.6 at 470 nm). [93] Furthermore, macroscopic onedimensional perovskite crystals exhibit the same properties as single nanowires regardless of the size of bulk crystals, which is considered a lead-free and low-cost polarization-sensitive crystal material.…”