Bulk photovoltaic effect (BPVE) triggered by spontaneous polarization in polar organic–inorganic hybrid perovskites (OIHPs) has brought unprecedented development opportunities for self-powered ultraviolet photodetection. However, the currently reported ultraviolet optoelectronic devices are dominated by low-dimensional hybrid perovskites, in which low carrier mobility limits the photoelectric conversion efficiency. Herein, we report for the first time a polar three-dimensional OIHPs, namely MHyPbBr 3 ( 1 , MHy=methylhydrazine), that achieves high-performance self-driven ultraviolet photodetection. Benefitting from the large spontaneous polarization and excellent semiconductor attributes, 1 exhibits 0.33 V BPVE and high carrier mobility lifetime product ( μτ ) of 1.972×10 −3  cm −2  V −1 under ultraviolet illumination. Notably, such merits contribute to efficient self-driven photodetection, where responsivity ( R ) and detectivity ( D *) reach up to 198 mA W −1 and 1.42×10 13 Jones, surpassing most reported ultraviolet photodetectors. Furthermore, based on the reversible phase transition of 1 , we have achieved controllable ultraviolet photoelectric detection. This work will shed light on the fabrication of high-response self-driven ultraviolet optoelectronic devices.

Two-dimensional（2D） organic-inorganic hybrid perovskites（OIHPs） have been developed as promising candidates for photodetection, owing to their excellent semiconducting features and structural tunability.However, as an important parameter for photodetection, the photoresponsive range of 2D OIHPs is usually modulated by finite metal-halide combinations, constraining their further development. The emerging aromatic amine-based alternating-cations-interlayered（A-ACI） hybrid perovskites that exhibit excellent charge transport and additional interlayered structural designability, provide an extra solution for achieving ideal photoresponsive range. Herein, for the first time, the photoresponsive range is successfully broadened in A-ACI hybrid perovskites（NMA） 4 （FA） 2 Pb 3 Br 12 （2） remolding from（NMA） 4 （MA） 2 Pb 3 Br 12 （1）(NMA = N-methylbenzylaminium, FA = formamidinium and MA = methylammonium). Particularly, 1 and 2adopt an unprecedented configuration that NMA and MA/FA are alternately arranged in the interlayer in a 4:2 manner. Importantly, 2 exhibits a narrower bandgap than 1, which can be ascribed to the lowlying conduct band composed of intercalation FA π*orbitals. Meanwhile, 2 possesses a shorter interlayer distance and flatter inorganic skeleton, synergistically facilitating the wider photo-absorption range and further endowing a broadening photoresponsive range（70 nm）. This research not only enriches the perovskite family but also provides insights into structure-property relationships.

2D hybrid perovskites, with their high X-ray absorption and extended carrier transport, present excellent promise for efficient direct X-ray detection. However, most of the current devices require external bias voltage, which results in the need for significant energy consumption and severe ion migration, therefore, it is urgent to develop new types of materials for achieving efficient passive X-ray detection. Herein, two novel chiral polar alternating cations intercalation (ACI)-type hybrid perovskite materials, named (R/S-PPA)(IEA)PbBr4 (1-R/S, (R/S)-PPA = R/S-1-phenylpropylamine; IEA = iodoethylamine), are constructed by integrating the chiral aromatic spacer R/S-PPA and the iodine-substituted spacer IEA. Various intermolecular interactions, such as II, C & horbar;HI, pipi interactions, are introduced due to the introduction of I-substituted chain amines, which effectively suppresses ion migration and thus lead to improved operational stability. The device constructed along the polar axis displays superior X-ray detection performance, such as relatively high sensitivity and an ultra-low limit of detection (LoD) of 3.0 nGy s-1, making it the first chiral ACI-type perovskite material for realizing efficient passive X-ray detection. Furthermore, 1-R also presents low dark current drift and exceptional irradiation stability. This work provides new thought for using novel ACI-type polar perovskite for high-performance passive direct X-ray detection. Two novel chiral-polar ACI-type perovskites are designed by introducing I-substituted cations with chiral aromatic cations, which have several types of weak interaction forces and further promote structural stability. The 1-R device is the first chiral ACI-type perovskite to enable passive X-ray detection with ultra-low detection limit and high radiation stability. image

The stereochemical expression of the ns(2) lone pair significantly impacts symmetry breaking and corresponding photoelectric properties. However, hindered by the symmetric octahedral configuration, the Pb2+ 6s(2) lone pair in the well-conductive lead halide hybrid perovskites (LHHP) are normally stereo-inactive, new approaches to activate the 6s(2) lone pair are still greatly desired. Herein, by exploiting a perovskitizer tuning Pb2+ lone pair method, the study successfully obtains a stereo-active 6s(2) in the polar perovskite PA2MHy2Pb3Br10 (PMPB, PA = n-propylamine, MHy = methylhydrazine), and unprecedentedly performs a multiaxial self-powered X-ray detection. In detail, the stereo-active 6s2 lone pair is caused by the coordination bond between the perovskitizer MHy and Pb atom. Emphatically, the N-Pb bond induces a large angular distortion parameter (approximate to 45 times larger than other LHHP) and the lowest-symmetric space group (P1) crystallization. Therefore, PMPB natively contains multiaxial polarization, which acts as the driving force to separate and transport the X-ray-generated carriers, thus enabling multiaxial self-powered X-ray detection with a low detection limit (129 nGy s(-1)). This work reveals the relationship between stereo-active lone pair and polarization and sheds light on future X-ray detection.

Three-dimensional (3D) organic–inorganic hybrid perovskites (OIHPs) have achieved tremendous success in direct X-ray detection due to their high absorption coefficient and excellent carrier transport. However, owing to the centrosymmetry of classic 3D structures, these reported X-ray detectors mostly require external electrical fields to run, resulting in bulky overall circuitry, high energy consumption, and operational instability. Herein, we first report the unprecedented radiation photovoltage in 3D OIHP for efficient self-driven X-ray detection. Specifically, the 3D polar OIHP MhyPbBr 3 ( 1 , Mhy=methylhydrazine) shows an intrinsic radiation photovoltage (0.47 V) and large mobility-lifetime product (1.1×10 −3  cm 2  V −1 ) under X-ray irradiation. Strikingly, these excellent physical characteristics endow 1 with sensitive self-driven X-ray detection performance, showing a considerable sensitivity of 220 μC Gy −1  cm −2 , which surpasses those of most self-driven X-ray detectors. This work first explores highly sensitive self-driven X-ray detection in 3D polar OIHPs, shedding light on future practical applications.

Metal halide perovskites (MHPs) have shown great potential for direct X-ray detection, but achieving high sensitivity without external bias remains challenging. Chiral-polar alternating cation intercalation (ACI)-type MHPs, with excellent optoelectronic properties and a robust chirality-induced bulk photovoltaic effect (BPVE), offer a promising platform for self-driven X-ray detection. Herein, impressive self-driven X-ray detection performance was achieved by utilizing chiral-polar 2D ACI-type perovskite single crystals of (R-PPA)PAPbBr4 (1R; R-PPA = R-1-phenylpropylamine; PA = propylamine). The chiral R-PPA cations induce the crystallization of 1R in the chiral-polar space group P21, wherein its spontaneous electric polarization further induces a strong BPVE. Consequently, 1R shows remarkable radiation photovoltaics of 0.75 V, which endows its excellent self-driven X-ray detection with a high sensitivity of 417.2 μC Gy-1 cm-2 and a low detection limit of 24.1 nGy s-1, meeting the state-of-the-art level by leveraging its intrinsic photovoltaic effect. These findings highlight the huge potential of chiral-polar ACI-type MHPs in self-driven X-ray detection applications.

Metal halide perovskite ferroelectrics combining spontaneous polarization and excellent semiconducting properties is an ideal platform for enabling self-driven X-ray detection. However, achievements to date have been only based on uniaxiality, which increases the complexity of device fabrication. Multi-axial ferroelectric materials have multiple equivalent polarization directions, making them potentially amenable to multi-axial self-driven X-ray detection, but the report on these types of materials is still a huge blank. Herein, a high-quality (BA) 2 (EA) 2 Pb 3 I 10 ( 1 ) biaxial ferroelectric single crystal was successfully grown, which exhibited significant spontaneous polarization along the c -axis and b -axis. Under X-ray irradiation, bulk photovoltaic effect (BPVE) was exhibited along both the c -axis and b -axis, with open circuit voltages ( V oc ) of 0.23 V and 0.22 V, respectively. Then, the BPVE revealed along the inversion of polarized direction with the polarized electric fields. Intriguingly, due to the BPVE of 1 , 1 achieved multi-axial self-driven X-ray detection for the first time ( c -axis and b -axis) with relatively high sensitivities and ultralow detection limits (17.2 nGy air  s −1 and 19.4 nGy air  s −1 , respectively). This work provides a reference for the subsequent use of multi-axial ferroelectricity for multi-axial self-driven optoelectronic detection.

Polar photovoltaic effect (PPE) has attracted great attention in regulating desired optoelectronic properties, which can be driven by order-disorder and displacive phase transitions. Bond-switching is also a feasible method to induce PPE, but such investigation is very rare. Lead-halide hybrid perovskite (LHHP) is an outstanding photodetection material; lead atoms possess rich coordination modes to provide possibilities to construct switchable bonds. Here, a unique perovskitizer N─Pb bond-switching is disclosed to induce polar photovoltage in the emerging LHHP, PA2MHy2Pb3Br10 (1, PA = n-propylamine, MHy = methylhydrazine). Interestingly, the perovskitizer MHy+ provides 2s2 lone pair while the Pb atom affords empty d orbitals, which coordinate with each other to generate a flexible N─Pb bond. Further, the introduction of N─Pb bonds results in a high distortion of the PbBr6 octahedron to form local polarity and further orientation to induce spontaneous polarization. More importantly, such a flexible N─Pb bond switching mechanism drives a notable PPE and controllable polarized photo-response, a polarization ratio up to 9.7 at the polar phase in striking contrast with the non-polar phase (1.03). The work provides the first demonstration of bond-switching to induce polar phase transition and polar photovoltage in the photoconductive hybrid perovskites for photoelectric applications.

Chiral lead-free halide double perovskites A 4 B I B III X 8 (A = chiral organic cations) are highly desirable because of their environmental friendliness and chiral functionality, but they are rarely reported. Herein, through the strategy of chiral-achiral cation intercalation, we rationally design enantiomeric lead-free halide double perovskites with the formula (A) 2 (A 0 ) 2 B I B III X 8 (A = chiral organic cations, A 0 = achiral organic cations). Experimentally, on the basis of the reported achiral LHDP (BA) 4 AgBiBr 8 , we obtained a series of six enantiomeric lead-free halide double perovskites-( R- PPA) 2 (BA) 2 AgBiBr 8 and ( S- PPA) 2 (BA) 2 AgBiBr 8 , ( R- PPA) 2 (Br- PA) 2 AgBiBr 8 and ( S- PPA) 2 (BrPA) 2 AgBiBr 8 , and ( R- PPA) 2 (BrEA) 2 AgBiBr 8 and ( S- PPA) 2 (BrEA) 2 AgBiBr 8 (PPA = 1-phenylpropylamine, BA = n-butylaminium, BrPA = 3-bromopropylaminium, BrEA = 2-bromoethylaminium)-demonstrating the feasibility of this synthesis strategy. Chiral cations and achiral cations arrange alternatingly in the interlayer and connect by diverse noncovalent intermolecular interactions, such as CH center dot center dot center dot p , p center dot center dot center dot p , and CH center dot center dot center dot Br. Consequently, the diverse arrangements and combinations of chiral A and achiral A 0 cations bring abundant chiral functionalities and robust circular dichroism signals.

Polar metal halide hybrid perovskites (PHPs) that exhibit outstanding bulk photovoltaic effect (BPVE), excellent semiconductor features, and strong radiation absorption ability, have shown prominent advantages in highly sensitive direct X-ray detection. However, it is still a challenge to explore PHPs with high BPVE temperature ranges, answering the demand of developing thermally stable passive X-ray detection. Herein, by intercalating arylamine into lead tribromide and inducing order-disorder phase transition, a 2D multilayered PHPs (BZA)2(MA)Pb2Br7 (BZPB, BZA = benzylamine, MA = methylamine) is synthesized. BZPB crystallizes in a polar space group Aea2 at a low-temperature phase and demonstrates a significant open-circuit of 0.3 V deriving from BPVE under X-ray irradiation. Meanwhile, the strong X-ray absorption coefficient and outstanding carrier transport capability of the bilayered lead halide framework associated with the polar BPVE give BZPB excellent X-ray detection abilities. At 0 V bias, the impressive sensitivity of BZPB is 98 mu C Gy-1 cm-2. Importantly, the introduction of the rigid BZA ring increases the energy barrier of phase transition and thus dramatically enhances the X-ray detection operating temperature of BZPB up to 409 K without significant performance degradation. This work strongly reveals the great potential of rational design of metal halide hybrid perovskites for X-ray detection applications. Through the arylamine intercalation strategy and inducing ordered-disordered phase transition, high operating-temperature self-powered X-ray detection based on (BZA)2(MA)Pb2Br7 is successfully realized. The large-sized arylamine provides a larger energy barrier of phase transition for increasing the phase transition temperature. This work demonstrates the great potential of the rational design of PHPs structures for X-ray detection applications. image

Polar 3D organic-inorganic hybrid perovskites (OIHPs) with the bulk photovoltaic effect (BPVE) have important application value in self-driven X-ray detection, due to their excellent semiconductor properties. However, A-site cations are limited by the tolerance factor, making it difficult to construct ABX3-type polar 3D perovskites. Therefore, it is necessary to explore polar 3D perovskitiods with excellent semiconductor properties for self-driven X-ray detection. Herein, by introducing an asymmetric diamine 3-methylaminopropylamine (3-MAPA) cation, a polar 3D perovskitiod, (3-MAPA)Pb2Br6 (1) is successfully constructed. Specifically, the dipole-oriented arrangement and intrinsic polarity of 3-MAPA cations endow a non-centrosymmetric structure of 1 single crystal (SC). Notably, under X-ray irradiation, the polar 1 SC exhibits a remarkable bulk photovoltaic of 0.8 V, which is beneficial for self-driven X-ray detection. Consequently, the 1-based detector shows a sensitivity of 101 µC Gy-1 s-1 and a low detection limit of 189 nGy s-1 at 0 V bias. Meanwhile, 1 SC-based X-ray detector exhibits less ion migration due to the abundant N─H···Br hydrogen bonding interaction within the structure, leading to a smaller dark current drift, which supports stable X-ray detection. This study attains stable self-driven X-ray detection based on polar 3D perovskitiods, which enriches the candidates for self-driven X-ray detectors.

Chiral hybrid perovskites combine the advantages of chiral materials and halide perovskites, offering an ideal platform for the design of circularly polarized light (CPL) detectors. The pyro-phototronic effect, as a special mechanism of the photoexcited pyroelectric signal, can significantly improve the performance of photodetectors, whereas it remains a great challenge to achieve pyroelectricity-based CPL detection. In this work, the chiroptical phenomena and the pyro-phototronic effect are combined in chiral-polar perovskites to achieve unprecedented pyroelectric-based CPL detection. Two novel two-dimensional (2D) lead-free chiral-polar double perovskites, S/R-[(4-aminophenyl)ethylamine]2AgBiI8·0.5H2O, are successfully designed and synthesized by introducing chiral organic ligands into metal halide frameworks. Strikingly, the photoresponse is substantially boosted with the support of the pyro-phototronic effect, showing an increased pyro-phototronic current that is 40 times greater than the photovoltaic current. Furthermore, the pyroelectric-based detector possesses excellent CPL detection capacity to distinguish different polarization states of CPL photons, which achieve an impressive glph of up to 0.27 at zero bias. This study provides a brand new process for CPL detection by utilizing the pyro-phototronic effect in chiral-polar perovskites, which opens a new avenue for chiral materials in optoelectronic applications.

Weak shortwave light photodetection with a low detection limit was achieved via centimeter-size single crystals of 2D perovskite (PA) 2 PbBr 4 . Under an extremely low illumination of 20 nW cm −2 , the detector still exhibits a remarkable photoresponse.

Organic–inorganic hybrid MAPbCl 3 perovskite (MA + = CH 3 NH 3 + ) in UV photodetection is drawing interest due to its superior semiconductor properties and UV‐matchable optical bandgap. However, MAPbCl 3 ‐based photodetector targeting high‐performance polarized light detection has remained unexplored due to the isotropic structure of MAPbCl 3 . The photovoltaic effect in the heterojunction, which shows an angle dependence on light polarization, provides opportunities to break the restriction of intrinsic structure for realizing polarization‐sensitive photodetection. Herein, an effective strategy is reported to realize high‐performance polarization‐sensitive UV photodetection by constructing a heterojunction with two isotropic materials MAPbCl 3 and Silicon (Si). Emphatically, the photovoltage in MAPbCl 3 /Si heterojunction changes with the angle of polarized light with the maximum (minimum) value of 0.15 V (0.05 V), originating from the built‐in electric field. More interestingly, driven by the photovoltage, the device thus exhibits a large polarization ratio ( I max / I min ) of 2.9 at 377 nm under the self‐driven mode. Besides, the present device also delivers high‐performance photodetection in UV region owing to the superior photoresponse of MAPbCl 3 , including a high detectivity ( D* ) of 2.93 × 10 11 Jones, a superior responsibility of 8 mA W –1 , a substantial switching ratio of 900, and an ultrafast response speed of 40/98 µs at 0 V bias. This work opens a new avenue for high‐performance polarization‐sensitive photodetection by utilizing angle‐dependent photovoltage effect.

Chiral perovskites have been demonstrated as promising candidates for direct circularly polarized light (CPL) detection due to their intrinsic chirality and excellent charge transport ability. However, chiral perovskite-based CPL detectors with both high distinguishability of left- and right-handed optical signals and low detection limit remain unexplored. Here, a heterostructure, (R-MPA)2 MAPb2 I7 /Si (MPA = methylphenethylamine, MA = methylammonium) is constructed, to achieve high-sensitive and low-limit CPL detection. The heterostructures with high crystalline quality and sharp interface exhibit a strong built-in electric field and a suppressed dark current, not only improving the separation and transport of the photogenerated carriers but also laying a foundation for weak CPL signals detection. Consequently, the heterostructure-based CPL detector obtains a high anisotropy factor up to 0.34 with a remarkably low CPL detection limit of 890 nW cm-2 under the self-driven mode. As a pioneering study, this work paves the way for designing high-sensitive CPL detectors that simultaneously have great distinguishing capability and low detection limit of CPL.

Bulk photovoltaic effect, a promising optoelectronic phenomenon for generating polarized dependent steady-state photocurrent, has been widely applied in various photodetectors. However, incorporating stereochemically active lone pair to construct bulk photovoltage in organic-inorganic hybrid perovskite (OIHP) is still elusive and challenging. Herein, bulk photovoltage (1.2 V) has been successfully achieved by introducing the stereo-chemically active lone pair perovskitizer to construct a polar tri-layered hybrid perovskite, namely, (IBA) 2 MHy 2 Pb 3 Br 10 ( 1 , IBA=iso-butylamine, MHy=methylhydrazine). Strikingly, owning to the promising bulk photovoltage, 1 -based detectors exhibit an ultra-highly sensitive polarized photodetection (polarization ratio of up to 24.6) under self-powered mode. This ratio surpasses all the reported two-dimension OIHP single-crystal photodetectors. In addition, detectors exhibit outstanding responsivity (≈200 mA W −1 ) and detectivity (≈2.4×10 13 Jones). More excitingly, further investigation confirms that lone pair electrons in MHy + result in the separation of positive and negative charges to produce directional dipoles, which further directional alignment to generate bulk photovoltage, thereby resulting in polarization-dependent photocurrent. Our findings provide a new demonstration for polar multilayer materials’ construction and may open opportunities for a host of high-sensitive polarized photodetection.

Motivated by the high performance of optoelecparticularly three-dimensional (3D) OIHPs, have taken a promising position in optoelectronic devices, owing to their high absorption coefficient, long carrier lifetime, and superior conversion efficiency. However, 3D OIHPs inevitably suffer from destruction under moisture operating conditions; it is a great struggle to synchronously realize high performance and long-term stability in optoelectronic devices. Herein, bulk single crystals (6 x 2 x 1.5 mm(3)) of the 3D hybrid perovskitoid (C6H10N2)Pb2Br6 (1, C6H10N22+ = N,N '-dimethyl-pyrazinium) have been grown successfully, which exhibit an excellent light absorption capacity (730 nm) and superior stability. Based on the bulk crystals of 1, photodetectors are fabricated with an extremely low dark current (3.5 pA), large current on/off ratio (>10(3)), considerable responsivity (R, 4 mA W-1), and detectivity (D*, 4 x 10(10) Jones). Strikingly, these devices possess excellent working stability (over 90 days) under ultralong air exposure, which are much better than most of the reported 3D OIHP devices. Furthermore, both experimental and computational investigations reveal that the excellent stability originates from the hydrophobic property of alkyl groups in C6H10N22+ cations. All of these results not only provide an efficient avenue to acquire 3D perovskitoid bulk single crystals but also inspire further exploration of ultrastable photoelectric devices.