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Polarization-sensitive photodetection is central to optics applications and has been successfully demonstrated in photodetectors of two-dimensional (2D) materials, such as layered hybrid perovskites; however, achieving high polarization sensitivity in such a photodetector remains extremely challenging. Here, for the first time, we demonstrate a high-performance polarization-sensitive photodetector using single-crystalline 2D/3D perovskite heterostructure, namely, (4-AMP)(MA)2Pb3Br10/MAPbBr3 (MA = methylammonium; 4-AMP = 4-(aminomethyl)piperidinium), which exhibits ultrahigh polarization sensitivity up to 17.6 under self-driven mode. To our knowledge, such a high polarization selectivity has surpassed all of the reported perovskite-based devices, and is comparable to, or even better than, the traditional inorganic heterostructure-based photodetectors. Further studies reveal that the built-in electric field formed at the junction can spatially separate the photogenerated electrons and holes, reducing their recombination rate and thus enhancing the performance for polarization-sensitive photodetection. This work provides a new source of polarization-sensitive materials and insights into designing novel optoelectronic devices. [ABSTRACT FROM AUTHOR]

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 self‐powered 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)2PbBr4 (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 UV‐polarized photodetectors (ZnO, GaN, and GeS2). [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid perovskite heterostructures, particularly 2D/3D perovskite heterostructures, have enjoyed great success in optoelectronic field. However, the photodetection performance of those heterostructures is obscured by extensive disorder in their polycrystalline films. Here, a delicate solution method is demonstrated for creating a sizable crystal of vertical 2D/3D perovskite heterostructure featuring a well‐defined interface and high single‐crystalline quality, namely (4‐AMP)(MA)2Pb3Br10/MAPbBr3 (MA, methylammonium; 4‐AMP, 4‐(aminomethyl)piperidinium). These high‐quality crystals are ideal mediums for charge transport and exploiting their optoelectronic properties. Electrical transport measurements demonstrate that the (4‐AMP)(MA)2Pb3Br10/MAPbBr3 heterostructure can form vertical diode with obvious current rectification behavior and excellent photocurrent generation characteristics. Strikingly, benefitting from the built‐in electrical potential at the junction, photodetectors based on those millimeter‐thickness heterostructure crystals exhibit high performance in self‐driven operation mode, including large on/off switching radio (≈105), fast response time (600/600 µs), and high detectivity (≈1012). This work enables an important advance in the development of single‐crystalline perovskite heterostructures for both fundamental demonstrations and high‐performance optoelectronic devices. [ABSTRACT FROM AUTHOR]

Polarized light detection is attracting increasing attention for its wide applications ranging from optical switches to high‐resolution photodetectors. Two‐dimensional (2D) hybrid perovskite‐type ferroelectrics combining inherent light polarization dependence of bulk photovoltaic effect (BPVE) with excellent semiconducting performance present significant possibilities. Now, the BPVE‐driven highly sensitive polarized light detection in a 2D trilayered hybrid perovskite ferroelectric, (allyammonium)2(ethylammonium)2Pb3Br10 (1), is presented. It shows a superior BPVE with near‐band gap photovoltage of ca. 2.5 V and high on/off switching ratio of current (ca. 104). Driven by the superior BPVE, 1 exhibits highly sensitive polarized light detection with a polarization ratio as high as ca. 15, which is far more beyond than those of structural anisotropy‐based monocomponent devices. This is the first realization of BPVE‐driven polarized light detection in hybrid perovskite ferroelectrics. [ABSTRACT FROM AUTHOR]

Inorganic–organic hybrid perovskites, especially two‐dimensional (2D) layered halide perovskites, have attracted significant attention due to their unique structures and attractive optoelectronic properties, which open up a great opportunity for next‐generation photosensitive devices. Herein, we report a new 2D bilayered inorganic–organic hybrid perovskite, (C6H13NH3)2(NH2CHNH2)Pb2I7 (HFA, where C6H13NH3+ is hexylaminium and NH2CHNH2+ is formamidinium), which exhibits a remarkable photoresponse under broadband light illumination. Structural characterizations demonstrate that the 2D perovskite structure of HFA is constructed by alternant stacking of inorganic lead iodide bilayered sheets and organic hexylaminium layers. Optical absorbance measurements combined with density functional theory (DFT) calculations suggest that HFA is a direct band gap semiconductor with a narrow band gap (Eg) of ≈2.02 eV. Based on these findings, photodetectors based on HFA crystal wafer are fabricated, which exhibit fascinating optoelectronic properties including large on/off current ratios (over 103), fast response speeds (τrise=310 μs and τdecay=520 μs) and high responsivity (≈0.95 mA W−1). This work will contribute to the design and development of new two‐dimensional bilayer inorganic–organic hybrid perovskites for high‐performance photosensitive devices. [ABSTRACT FROM AUTHOR]

Abstract: Although organic‐inorganic hybrid perovskites demonstrate promising potentials for photodetection, one great challenge still to be addressed is their relatively low responding speed (often at the magnitude order of ∼ms). Herein, a solution‐processed photodetector based on polar two‐dimensional (2D) multilayered hybrid perovskite crystal is fabricated, (C5H11NH3)2(CH3NH3)Pb2I7 (EMA, where C5H11NH3+ is n‐pentylaminium), which exhibits an ultrafast responding time of ≈1.52 μs. This figure‐of‐merit is faster at least by 2–4 orders than other reported 2D organic‐inorganic hybrid perovskite photodetectors. To the best of knowledge, this is the record‐fast response‐speed for lateral‐type devices of 2D organic‐inorganic hybrid perovskite. Such ultrafast responding can be attributed to the high crystallinity and quite low density of defects and traps. In addition, this device also presents a high photocurrent on/off ratio (>103) and extremely low dark current (≈10−10 A), indicating its potential applications for high‐efficiency photodetectors. Our results pave the pathway toward ultrafast responding photodetection of 2D organic‐inorganic hybrid perovskites. [ABSTRACT FROM AUTHOR]

Abstract: Large‐size crystals of organic–inorganic hybrid perovskites (e.g., CH3NH3PbX3, X = Cl, Br, I) have gained wide attention since their spectacular progress on optoelectronic technologies. Although presenting brilliant semiconducting properties, a serious concern of the toxicity in these lead‐based hybrids has become a stumbling block that limits their wide‐scale applications. Exploring lead‐free hybrid perovskite is thus highly urgent for high‐performance optoelectronic devices. Here, a new lead‐free perovskite hybrid (TMHD)BiBr5 (TMHD = N,N,N,N‐tetramethyl‐1,6‐hexanediammonium) is prepared from facile solution process. Emphatically, inch‐size high‐quality single crystals are successfully grown, the dimensions of which reach up to 32 × 24 × 12 mm3. Furthermore, the planar arrays of photodetectors based on bulk lead‐free (TMHD)BiBr5 single crystals are first fabricated, which shows sizeable on/off current ratios (≈103) and rapid response speed (τrise = 8.9 ms and τdecay = 10.2 ms). The prominent device performance of (TMHD)BiBr5 strongly underscores the lead‐free hybrid perovskite single crystals as promising material candidates for optoelectronic applications. [ABSTRACT FROM AUTHOR]

Two-dimensional (2D) layered hybrid perovskites have shown great potential in optoelectronics, owing to their unique physical attributes. However, 2D hybrid perovskite ferroelectrics remain rare. The first hybrid ferroelectric with unusual 2D multilayered perovskite framework, (C4H9NH3)2(CH3NH3)2Pb3Br10 ( 1), has been constructed by tailored alloying of the mixed organic cations into 3D prototype of CH3NH3PbBr3. Ferroelectricity is created through molecular reorientation and synergic ordering of organic moieties, which are unprecedented for the known 2D multilayered hybrid perovskites. Single-crystal photodetectors of 1 exhibit fascinating performances, including extremely low dark currents (ca. 10−12 A), large on/off current ratios (ca. 2.5×103), and very fast response rate (ca. 150 μs). These merits are superior to integrated detectors of other 2D perovskites, and compete with the most active CH3NH3PbI3. [ABSTRACT FROM AUTHOR]

2D organic–inorganic hybrid perovskites are emerging as the promising alternatives in photodetection, due to their unique merits stemming from intrinsic quantum‐confined structures. Despite great ongoing effects, highly sensitive and ultrafast responding photodetectors of 2D hybrid perovskites remain a huge blank. Here, the first nanosecond‐responsive array photodetector based on 2D perovskite crystals of (PA)2(G)Pb2I7 (where PA = n‐pentylaminium and G = guanidinium) is fabricated, which features a newly tailored bilayer motif with large‐size G cation as "perovskiter" inside the distorted PbI3 perovskite framework. This motif creates a new branch of the intriguing 2D hybrid perovskite family. Strikingly, both high photodetectivities (6.3 × 1012 Jones) and responsivities (≈47 A W−1), as well as low dark current (≈2.4 × 10−11 A), are achieved in this array photodetector. Further, its ultrafast response time (τ) of 3.1 ns is one of the record‐fast merits for 2D hybrid perovskites. Such attributes originate from its strong in‐plane photoresponse related to perovskite network and low dark current inhibited by the hopping barriers of insulating PA bilayers. All these characteristics make (PA)2(G)Pb2I7 a promising candidate for photodetection, and pave the way to explore new 2D hybrid perovskite candidates for future high‐performance optoelectronic devices. [ABSTRACT FROM AUTHOR]