Search

Photoexcited pyroelectricity in ferroelectrics allows the direct conversion of light radiation into electric signal without external power source, thus paving an avenue to promote optoelectronic device performances. However, it is urgently demanded to exploit new ferroelectrics with this attribute covering ultraviolet (UV)‐to‐infrared (IR) region for self‐powered photodetection. Herein, broadband light‐induced pyroelectric effects in a new 2D perovskite‐type ferroelectric, (BBA)2(EA)2Pb3Br10 (1; BBA = p‐bromobenzylammonium, EA = ethylammonium), showing a high Curie temperature of 425 K and notable pyroelectric coefficient (≈5.4 × 10−3 µC cm−2 K−1) is presented. Especially, photo‐induced change of its electric polarization leads to ultraviolet‐to‐infrared pyroelectricity in a wide spectral region (377–1950 nm). Broadband photoactivities actualized by this property break the limitation of its optical bandgap. Thus, single‐crystal detectors of 1 are sensitive to UV‐to‐IR light with a small temperature fluctuation of 0.3 K, exhibiting a high transient responsivity up to ≈0.28 mA W−1 and specific detectivity of 1.31 × 1010 Jones under zero bias (at 405 nm); such figure‐of‐merits are beyond than those self‐powered photodetectors using oxide ferroelectrics. It is anticipated that the findings of light‐induced pyroelectricity afford a feasible strategy to assemble newly‐conceptual smart photoelectric devices, such as self‐powered broadband detectors. [ABSTRACT FROM AUTHOR]

Broadband photodetection has shown a great promise for diverse applications, while the realization of plateau photoresponse from ultraviolet (UV) to near‐infrared (NIR) spectral region is very challenging. Herein, we exploit photoexcited pyroelectric effect in a chiral hybrid perovskite, (N, N‐dimethylcyclohexylammonium)PbBr3 (1), serving as a new pathway to drive broadband photoactivities. It is a room‐temperature pyroelectric with large polarization of ≈6.4 μC cm−2 and high pyroelectric figure‐of‐merits (FV=1.0×10−2 cm2 μC−1 and FD=7.1×10−5 Pa−1/2). Strikingly, light‐induced pyroelectric effect arising from spontaneous polarization is observed in 1, which cover UV (266 nm) to NIR‐II (1950 nm) full spectral region. The broadband photoresponses actualized by pyroelectricity break the limit of optical band gap. As the first demonstration of photo‐pyroelectricity covering UV‐to‐NIR spectral region in hybrid perovskites, this work paves a pathway to assemble high‐performance smart devices. [ABSTRACT FROM AUTHOR]

Chiral alternating cations intercalation‐type (ACI) perovskites, which are capable of great structural flexibility and a suitable quantum well barrier thickness that facilitates better charge transport, are urgently desired for circularly polarized light (CPL) detection. However, the chiral–polar photovoltaic effect (CPPE) in chiral ACI perovskites has never been reported although CPPE will provide great opportunities for future sustainable development. Here, by transmuting the organic ligands in 2D Ruddlesden–Popper‐type (RP) perovskites, two chiral–polar photovoltaic ACI perovskites (R/S‐PPA)EAPbCl4 (1R/1S) are successfully developed, which are stabilized by the alternating ordering of the short alkyl EA (EA = ethylammonium) and chiral aromatic PPA (PPA = 1‐phenylpropylamine) cations in the interlayer space. Particularly, converting chiral RP into ACI perovskites gives rise to a remarkable CPPE and suitable quantum well barrier thickness. These features contribute to the exploration of self‐powered ultraviolet CPL detection with an asymmetry factor up to 0.4, which reaches the highest value among the reported layered chiral perovskites. This is thought to be the first realization of CPPE in ACI perovskites, which paves the way for the application of chiral perovskites for self‐powered short‐wave ultraviolet CPL detection. [ABSTRACT FROM AUTHOR]

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)2(methylamium)Pb2Cl7 (1), in which the BPVE behaves as self‐driving source for solar‐blind ultraviolet polarized‐light detection. It exhibits a large dichroism ratio (≈15.7) and superior BPVE‐directed photocurrent (≈3.6 μA cm−2, under 266 nm). These attributes facilitate excellent self‐powered polarized‐light detection of high on/off contrast (≈103) and polarization ratio (≈2.5), beyond those of inorganic oxides (e.g. ZnO, 1.47; GaN, 1.38). This study highlights potential of 2D perovskite ferroelectrics for new optoelectronic application. [ABSTRACT FROM AUTHOR]

Polarized‐light detection in solar‐blind ultraviolet region is indispensable for optoelectronic applications, whereas new 2D candidates targeted at solar‐blind UV range remain extremely scarce. 2D hybrid perovskite ferroelectrics that combine polarization and semiconducting properties are of increasing interest. Here, using the 3D‐to‐2D dimensional reduction of CH3NH3PbCl3, we designed a multilayered hybrid perovskite ferroelectric, (CH3CH2NH3)2(CH3NH3)2Pb3Cl10, which shows spontaneous polarization and a high Curie temperature (390 K) comparable with that of BaTiO3 (393 K). The wide band gap (ca. 3.35 eV) and anisotropic absorbance stemming from its intrinsic 2D motif, greatly favor its polarization‐sensitive activity in UV region. The device displays excellent polarization‐sensitive behavior under 266 nm, along with a large dichroic ratio (ca. 1.38) and high on/off current ratio (ca. 2.3×103). [ABSTRACT FROM AUTHOR]