Design of an Ultrafast and Controlled Visible Light-Mediated Photoiniferter RAFT Polymerization for Polymerization-Induced Self-Assembly (PISA).

In this contribution, we designed a new xanthate RAFT agent by introducing (5,6,7,8-tetrahydro-2-naphthalenyl)oxy (TNO) as the Z group, namely 2-[(((5,6,7,8-Tetrahydro-2-naphthalenyl)oxycarbonothioyl)thio)ethyl propanoate] (TNXEP). Due to the presence of the TNO group, TNXEP enabled highly controlled and ultrafast photoiniferter RAFT polymerization under violet (λ=405 nm) and blue (λ=450 nm) light. This approach was effectively extended to aqueous media for polymerization-induced self-assembly (PISA), facilitating the synthesis of polymeric nanoparticles.

Field-Induced Antiferroelectric-Ferroelectric Transformation in Organometallic Perovskite Displaying Giant Negative Electrocaloric Effect.

Antiferroelectric materials with an electrocaloric effect (ECE) have been developed as promising candidates for solid-state refrigeration. Despite the great advances in positive ECE, reports on negative ECE remain quite scarce because of its elusive physical mechanism. Here, a giant negative ECE (maximum Δ ∼ -33.

Renewing Halogen Substitution Strategy for the Rational Design of High-Curie Temperature Metal-Free Molecular Antiferroelectrics.

Metal-free molecular antiferroelectric (AFE) holds a promise for energy storage on account of its unique physical attributes. However, it is challenging to explore high-curie temperature (T) molecular AFEs, due to the lack of design strategies regarding the rise of phase transition energy barriers. By renewing the halogen substitution strategy, we have obtained a series of high-T molecular AFEs of the halogen-substituted phenethylammonium bromides (x-PEAB, x=H/F/Cl/Br), resembling the binary stator-rotator system.

X-ray-Induced Pyroelectric Effect in a Perovskite Ferroelectric Drives Low Detection Limit Self-Powered Responses.

The light-induced pyroelectric effect (LPE) has shown a great promise in the application of optoelectronic devices, especially for self-powered detection and imaging. However, it is quite challenging and scarce to achieve LPE in the X-ray region. For the first time, we report X-ray LPE in a single-phase ferroelectric of (NPA)(EA)PbBr (, NPA = neopentylamine, EA = ethylamine), adopting a two-dimensional trilayered perovskite motif, which has a large spontaneous polarization of ∼3.

Mixing cage cations in 2D metal-halide ferroelectrics enhances the ferro-pyro-phototronic effect for self-driven photopyroelectric detection.

The ferro-pyro-phototronic (FPP) effect, coupling photoexcited pyroelectricity and photovoltaics, paves an effective way to modulate charge-carrier behavior of optoelectronic devices. However, reports of promising FPP-active systems remain quite scarce due to a lack of knowledge on the coupling mechanism. Here, we have successfully enhanced the FPP effect in a series of ferroelectrics, BACsMAPbBr (BA = butylammonium, MA = methylammonium, 0 ≤ ≤ 0.

Building Block-Inspired Hybrid Perovskite Derivatives for Ferroelectric Channel Layers with Gate-Tunable Memory Behavior.

Ferroelectric photovoltaics driven by spontaneous polarization (P ) holds a promise for creating the next-generation optoelectronics, spintronics and non-volatile memories. However, photoactive ferroelectrics are quite scarce in single homogeneous phase, owing to the severe P fatigue caused by leakage current of photoexcited carriers. Here, through combining inorganic and organic components as building blocks, we constructed a series of ferroelectric semiconductors of 2D hybrid perovskites, (HA) (MA) Pb Br (n=1-5; HA=hexylamine and MA=methylamine).

Polarization-Dependent Large Photorefractive Effect In A Wide Bandgap 2D Metal Halide Ferroelectric.

Photorefractive effect of ferroelectrics refers to the light-induced change of refractive index, which is an optical controlling avenue in holographic storage and image processing. For most ferroelectrics, however, the small photorefractive effect (10 -10 ) hinders their practical application and it is urgent to exploit new photorefractive system. Here, for the first time, strong photorefractive effects are achieved in a 2D metal-halide ferroelectric, [CH (CH ) NH ] (CH NH )Pb Cl (1), showing large spontaneous polarization (≈4.

Visible-Photoactive Perovskite Ferroelectric-Driven Self-Powered Gas Detection.

Chemiresistive sensing has been regarded as the key monitoring technique, while classic oxide gas detection devices always need an external power supply. In contrast, the bulk photovoltage of photoferroelectric materials could provide a controllable power source, holding a bright future in self-powered gas sensing. Herein, we present a new photoferroelectric ([-pentylaminium][ethylammonium]PbI, ), which possesses large spontaneous polarization (∼4.

Improper High-T Perovskite Ferroelectric with Dielectric Bistability Enables Broadband Ultraviolet-to-Infrared Photopyroelectric Effects.

The photopyroelectric effect in ferroelectrics has shown great potential for application in infrared detection and imaging. One particular subclass is broadband with dielectric bistability, which allows for large pyroelectric figures-of-merit (FOMs). Herein, an improper high-T perovskite ferroelectric, (IA) (EA) Pb Cl (1, where IA is isoamylammonium and EA is ethylammonium) is presented, in which spontaneous polarization (P ) stems from the dynamic ordering of organic cations and the tilting of distorted PbCl octahedra.

Acquiring Bulk Anomalous Photovoltaic Effect in Single Crystals of a Lead-Free Double Perovskite with Aromatic and Alkali Mixed-Cations.

The bulk anomalous photovoltaic (BAPV) effect of acentric materials refers to a distinct concept from traditional semiconductor-based devices, of which the above-bandgap photovoltage hints at a promise for solar-energy conversion. However, it is still a challenge to exploit new BAPV-active systems due to the lacking of knowledge on the structural origin of this concept. BAPV effects in single crystals of a 2D lead-free double perovskite, (BBA) CsAgBiBr (1, BBA = 4-bromobenzylammonium), tailored by mixing aromatic and alkali cations in the confined architecture to form electric polarization are acquired here.

A room-temperature antiferroelectric in hybrid perovskite enables highly efficient energy storage at low electric fields.

Molecular antiferroelectrics (AFEs) have taken a booming position in the miniaturization of energy storage devices due to their low critical electric fields. However, regarding intrinsic competitions between dipolar interaction and steric hindrance, it is a challenge to exploit room-temperature molecular AFEs with high energy storage efficiency. Here, we present a new 2D hybrid perovskite-type AFE, (i-BA)(FA)PbBr (1), which shows ultrahigh energy storage efficiencies at room temperature.

Soft Multiaxial Molecular Ferroelectric Thin Films with Self-Powered Broadband Photodetection.

Molecular ferroelectric films (MFFs) offer a good platform for miniaturized electronic devices, which are inseparable from their multiaxial nature. Despite great studies, soft MFFs with broadband photo-electroactivity still remain a huge blank as the photoexcited leakage current will severely deteriorate ferroelectricity, hindering their optoelectronic applications. Here, we constructed the multiaxial MFF of HAEAPbI (, where EA = ethylammonium and HA = -hexylammonium) in 2D multilayered perovskites.

Record high-T and large practical utilization level of electric polarization in metal-free molecular antiferroelectric solid solutions.

Metal-free antiferroelectric materials are holding a promise for energy storage application, owing to their unique merits of wearability, environmental friendliness, and structure tunability. Despite receiving great interests, metal-free antiferroelectrics are quite limited and it is a challenge to acquire new soft antiferroelectric candidates. Here, we have successfully exploited binary CMBrI and CMBrCl solid solution as single crystals (0 ≤ x ≤ 1, where CM is cyclohexylmethylammonium).

Comprehensive Analysis of Prognostic Value and Immune Infiltration of IGFBP Family Members in Glioblastoma.

Glioblastoma (GBM) is the most common primary malignant brain tumor in adults. The insulin-like growth factor-binding protein (IGFBP) family is involved in tumorigenesis and the development of multiple cancers. However, little is known about the prognostic value and regulatory mechanisms of IGFBPs in GBM.

Incorporating an Aromatic Cationic Spacer to Assemble 2D Polar Perovskite Crystals toward Self-Powered Detection of Quite Weak Polarized Light.

Two-dimensional (2D) hybrid perovskites with intrinsic attributes of structural and optical anisotropy are holding a bright promise for polarization-sensitive photodetection. However, studies on self-powered detection to quite weak polarized light remain scarce in this 2D family. By incorporating an aromatic spacer into the 3D cubic prototype, we have successfully assembled a new 2D hybrid perovskite with a polar motif, (FPEA)(MA)PbI (, where FPEA is 4-fluorophenethylammonium and MA is methylammonium).

Anisotropy in a 2D Perovskite Ferroelectric Drives Self-Powered Polarization-Sensitive Photoresponse for Ultraviolet Solar-Blind Polarized-Light Detection.

Polarized-light detection in the deep ultraviolet solar-blind region is indispensable for optoelectronic applications. 2D hybrid perovskite ferroelectrics with inherent anisotropy and bulk photovoltaic effect (BPVE) have become a robust candidate in this portfolio. We here report a wide band-gap 2D perovskite ferroelectric, (isobutylammonium) (methylamium)Pb Cl (1), in which the BPVE behaves as self-driving source for solar-blind ultraviolet polarized-light detection.

Ferroelectric perovskite-type films with robust in-plane polarization toward efficient room-temperature chemiresistive sensing.

Ferroelectric materials have become key components for versatile device applications, and their thin films are highly desirable for integrating the miniaturized devices. Despite substantial endeavors, it is still challenging to achieve effective chemiresistive sensing in the ferroelectric films. Here, for the first time, we have exploited ferroelectric thin films of 2D hybrid perovskite BAEAPbI (), to fabricate the high-performance chemiresistor gas sensors.

Tailoring Interlayered Spacers of Two-Dimensional Cesium-Based Perovskite Ferroelectrics toward Exceptional Ferro-Pyro-Phototronic Effects.

Ferro-pyro-phototronic (FPP) effect is a triple coupling of ferroelectricity, light-induced pyroelectricity, and photo-excitation, which holds a bright promise for next-generation modern optoelectronic devices. However, except for few oxides (e.g.

A Metal-Free Molecular Antiferroelectric Material Showing High Phase Transition Temperatures and Large Electrocaloric Effects.

Antiferroelectric (AFE) materials, featuring an antiparallel alignment of electric dipoles in the adjacent sublattices, are keeping a great promise toward solid-state refrigeration applications on account of their electrocaloric (EC) effects. Although extensive studies have been performed on inorganic oxide counterparts (e.g.

A reduced-dimensional polar hybrid perovskite for self-powered broad-spectrum photodetection.

Polar hybrid perovskites have been explored for self-powered photodetection benefitting from prominent transport of photo-induced carriers and the bulk photovoltaic effect (BPVE). However, these self-powered photodetection ranges are relatively narrow depending on their intrinsic wide bandgaps (>2.08 eV), and the realization of broad-spectrum self-powered photodetection is still a difficult task.

Two-Dimensional Guanidine-Based Hybrid Perovskites with Strong Dichroism for Multiwavelength Polarization-Sensitive Detection.

Two-dimensional (2D) organic-inorganic hybrid perovskites, benefiting from their natural anisotropy of quantum-well motifs and optical properties, have shown remarkable polarization-dependent responses superior to the 3D counterparts. Here, for the first time, multiwavelength polarization-sensitive detectors were fabricated by using single crystals of a guanidine-based 2D hybrid perovskite, (BA) (GA)Pb I (where BA is n-butylammonium and GA is guanidium). Its unique 2D quantum-well structure results in strong crystallographic-dependence of optical absorption.

Ultrasensitive polarized-light photodetectors based on 2D hybrid perovskite ferroelectric crystals with a low detection limit.

Polarized-light photodetectors are the indispensable elements for practical optical and optoelectronic device applications. Two-dimensional (2D) hybrid perovskite ferroelectrics, in which the coupling of spontaneous polarization (P) and light favors the dissociation of photo-induced carriers, have taken a booming position within this portfolio. However, polarized-light photodetectors with a low detection-limit remain unexplored in this 2D ferroelectric family.

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

Two-dimensional (2D) hybrid perovskites of Ruddlesden-Popper (RP) lattices are recently booming as a vigorous class of ferroelectrics, whereas their intrinsic van der Waals gaps exert weak interactions that destabilize the layered motifs. Thus, it is an urgent challenge to reduce interlayered energy gaps to allow an exploration of stable RP ferroelectrics. Here, we propose hydrogen bonds to reduce van der Waals gaps of 2D RP-type perovskites while the ferroelectricity is retained.