Acyloxyacyl hydrolase promotes pulmonary defense by preventing alveolar macrophage tolerance.

Although alveolar macrophages (AMs) play important roles in preventing and eliminating pulmonary infections, little is known about their regulation in healthy animals. Since exposure to LPS often renders cells hyporesponsive to subsequent LPS exposures ("tolerant"), we tested the hypothesis that LPS produced in the intestine reaches the lungs and stimulates AMs, rendering them tolerant. We found that resting AMs were more likely to be tolerant in mice lacking acyloxyacyl hydrolase (AOAH), the host lipase that degrades and inactivates LPS; isolated Aoah-/- AMs were less responsive to LPS stimulation and less phagocytic than were Aoah+/+ AMs. Upon innate stimulation in the airways, Aoah-/- mice had reduced epithelium- and macrophage-derived chemokine/cytokine production. Aoah-/- mice also developed greater and more prolonged loss of body weight and higher bacterial burdens after pulmonary challenge with Pseudomonas aeruginosa than did wildtype mice. We also found that bloodborne or intrarectally-administered LPS desensitized ("tolerized") AMs while antimicrobial drug treatment that reduced intestinal commensal Gram-negative bacterial abundance largely restored the innate responsiveness of Aoah-/- AMs. Confirming the role of LPS stimulation, the absence of TLR4 prevented Aoah-/- AM tolerance. We conclude that commensal LPSs may stimulate and desensitize (tolerize) alveolar macrophages in a TLR4-dependent manner and compromise pulmonary immunity. By inactivating LPS in the intestine, AOAH promotes antibacterial host defenses in the lung.

Wide Bandgap Semiconductors for Ultraviolet Photodetectors: Approaches, Applications, and Prospects.

Ultraviolet (UV) light, invisible to the human eye, possesses both benefits and risks. To harness its potential, UV photodetectors (PDs) have been engineered. These devices can convert UV photons into detectable signals, such as electrical impulses or visible light, enabling their application in diverse fields like environmental monitoring, healthcare, and aerospace. Wide bandgap semiconductors, with their high-efficiency UV light absorption and stable opto-electronic properties, stand out as ideal materials for UV PDs. This review comprehensively summarizes recent advancements in both traditional and emerging wide bandgap-based UV PDs, highlighting their roles in UV imaging, communication, and alarming. Moreover, it examines methods employed to enhance UV PD performance, delving into the advantages, challenges, and future research prospects in this area. By doing so, this review aims to spark innovation and guide the future development and application of UV PDs.

Indeno[3,2-b]carbazole-Based Small Molecule Layer Enables Optimized Carrier Transport for PbS Quantum Dot NIR Photodetectors.

Colloidal quantum dots (CQDs) have garnered considerable attention for photodetectors (PDs), attributable to exceptional photoelectric properties and ease solution-based processing. However, the prevalent use of 1,2-ethanedithiol (EDT) as a hole transport layer (HTL) has limitations, such as energy level discrepancies, requisite oxidation, and intricate multilayer assembly. Organic p-type materials, lauded for their superior attributes and synthetic versatility, are now stepping forward as viable substitutes for conventional EDT HTLs. In this work, we introduced an organic HTL derived from indolo[3,2-b]carbazole, named ZL004, leading to a marked improvement in carrier generation and collection, facilitated by the optimized band alignment and enhanced interfacial charge dynamics. The ZL004-based PDs exhibit a photoresponsivity of 0.45 A/W, a noise current of 1.8 × 10-11 A Hz-0.5, a specific detectivity of 4.6 × 109 Jones, and an expansive linear dynamic range of 107 dB─surpassing EDT-based devices across the board, demonstrating the extraordinary property of organic p-type materials for CQD-based PDs.

Compositional gradient engineering and applications in halide perovskites.

Organic-inorganic halide perovskites (HPs) have attracted respectable interests as active layers in solar cells, light-emitting diodes, photodetectors, etc. Besides the promising optoelectronic properties and solution-processed preparation, the soft lattice in HPs leads to flexible and versatile compositions and structures, providing an effective platform to regulate the bandgaps and optoelectronic properties. However, conventional solution-processed HPs are homogeneous in composition. Therefore, it often requires the cooperation of multiple devices in order to achieve multi-band detection or emission, which increases the complexity of the detection/emission system. In light of this, the construction of a multi-component compositional gradient in a single active layer has promising prospects. In this review, we summarize the gradient engineering methods for different forms of HPs. The advantages and limitations of these methods are compared. Moreover, the entropy-driven ion diffusion favors compositional homogeneity, thus the stability issue of the gradient is also discussed for long-term applications. Furthermore, applications based on these compositional gradient HPs will also be presented, where the gradient bandgap introduced therein can facilitate carrier extraction, and the multi-components on one device facilitate functional integration. It is expected that this review can provide guidance for the further development of gradient HPs and their applications.

Enhanced room-temperature terahertz detection and imaging derived from anti-reflection 2D perovskite layer on MAPbI3 single crystals.

Terahertz (THz) detection technology is getting increasing attention from scientists and industries alike due to its superiority in imaging, communication, and defense. Unfortunately, the detection of THz electromagnetic waves under room temperature requires a complicated device architecture design or additional cryogenic cooling units, which increase the cost and complexity of devices, subsequently imposing an impediment in its universal application. In this work, THz detectors operated under room temperature are designed based on the thermoelectric effect with MAPbI3 single crystals (SCs) as active layers. With solution-processed molecular growth engineering, the anti-reflection 2D perovskite layers were constructed on SCs' surfaces to suppress THz reflection loss. Simultaneously, by finely regulating the main carrier types and the direction of the applied bias across the inclined energy level, the thermoelectric effect is further promoted. As a result, THz-induced ΔT in MAPbI3 SCs reaches 4.6 °C, while the enhancement in the bolometric and photothermoelectric effects reach ∼4.8 times and ∼16.9 times, respectively. Finally, the devices achieve responsivity of 88.8 µA W-1 at 0.1 THz under 60 V cm-1, noise equivalent power (NEP) less than 2.16 × 10-9 W Hz-1/2, and specific detectivity (D*) of 1.5 × 108 Jones, which even surpasses the performance of state-of-the-art graphene-based room-temperature THz thermoelectric devices. More importantly, proof-of-concept imaging gives direct evidence of perovskite-based THz sensing in practical applications.

Further Advancement of Perovskite Single Crystals.

Halide perovskite (HP) single crystals (SCs) are garnering extensive attention as active materials to substitute polycrystalline counterparts in solar cells, photodiodes, and photodetectors, etc. Nevertheless, the large thickness and defect-rich surface results in severe carrier recombination and becomes the major bottleneck for augmented performance. In this perspective, we are looking forward to explaining in detail why the SCs hardly unleash their engrossing potential and introduce two parallel paths for further advancement. First is the modification of thick SCs by reducing the prepared thickness or surface passivation. Second is the large thickness that is conducive to the sufficient absorption of high-energy rays with strong penetrating ability and is beneficial to the thermoelectric effect due to the ultralow thermal conductivity of HPs. These applications provide a roundabout strategy to exploit freestanding SCs with a large thickness. Herein, direct modification and application of thick SCs are systematically introduced, expecting to give rise to the prosperity of HP SCs.

Monolithic RGB-NIR Perovskite Photodetector for Fused Multispectral Sensing and Imaging.

The multispectral fusion of near-infrared (NIR) and visible red-green-blue (RGB) photons can enhance target identification under weak light conditions. Nevertheless, the crosstalk between NIR and RGB photons in a traditional pixelated sensor impedes their practical application, while using complex algorithms and optical filters would significantly increase the cost, form factor, and frame latency. In this work, a delicate monolithic RGBN (RGB-NIR) multispectral photodetector (PD) is proposed on the basis of perovskite materials without complicated algorithms or optical filters. The multispectral response toward selective RGBN signals in this monolithic PD pixels can be achieved by switching the polarity of the applied bias, affording the following benefits: Ion/Ioff ratio of >104, detectivity of >1010 Jones, crosstalk of -74 dB, and fast response with -3 dB > 103 Hz. Moreover, proof-of-concept imaging of the iris and periocular with successful recognition in multispectral fusion further confirms its potential for identity authentication.

Flexible Miniaturized Multispectral Detector Derived from Blade-Coated Organic Narrowband Response Unit Array.

Multispectral sensing is extremely desired in intelligent systems, e.g., autonomous vehicles, encrypted information communication, and health biometric monitoring, due to its highly sensitive spectral discrimination ability. Nevertheless, rigid bulky optics and delicate optical paths in devices significantly increase their complexity and size, which subsequently impede their integration in smart optoelectronic chips for universal applications. In this work, a filterless miniaturized multispectral photodetector is realized with an organic narrowband response unit array. With the manipulation of Frenkel exciton dissociation in active layers, a series of narrowband organic sensing units with full-width-at-half-maximum (fwhm) narrowing to ∼50 nm are achieved from 700 to 1050 nm with a laudable performance of responsivity of over 60 mA/W, -3 dB bandwidth over 10 kHz, linear dynamic range (LDR) reaching ∼120 dB, and a low noise current of less than 4 × 10-14 A·Hz-0.5. Furthermore, a 6 × 8 multispectral sensing array on a flexible substrate was fabricated with blade-coating. Assisted by a computational process, we successfully demonstrate the spectral recognition with a resolution of ∼50 nm and a mismatch of ∼10 nm. Finally, the function of matter identification is successfully achieved with our multispectral detector array.

Miniaturized Multispectral Detector Derived from Gradient Response Units on Single MAPbX3 Microwire.

Miniaturized multispectral detectors are urgently desired given the unprecedented prosperity of smart optoelectronic chips for integrated functions including communication, imaging, scientific analysis, etc. However, multispectral detectors require complicated prism optics or interference/interferometric filters for spectral recognition, which hampers the miniaturization and their subsequent integration in photonic integrated circuits. In this work, inspired by the advance of computational imaging, optical-component-free miniaturized multispectral detector on 4 mm gradient bandgap MAPbX3 microwire with a diameter of 30 µm, is reported. With accurate composition engineering, halide ions in MAPbX3 microwire vary from Cl to I giving in the gradual variation of optical bandgap from 2.96 to 1.68 eV along axis. The sensing units on MAPbX3 microwire offer the response edge ranging from 450 to 790 nm with the responsivity over 20 mA W-1 , -3dB width over 450 Hz, LDR of ≈60 dB, and a noise current less than ≈1.4 × 10-12 A Hz-0.5 . As a result, the derived miniaturized detector achieves the function of multispectral sensing and discrimination with spectral resolution of ≈25 nm and mismatch of ≈10 nm. Finally, the proof-of-concept colorful imaging is successfully conducted with the miniaturized multispectral detector to further confirm its application in spectral recognition.

Oriented Perovskite Growth Regulation Enables Sensitive Broadband Detection and Imaging of Polarized Photons Covering 300-1050 nm.

Photodetectors selective to the polarization empower breakthroughs in sensing technology for target identification. However, the realization of polarization-sensitive photodetectors based on intrinsically anisotropic crystal structure or extrinsically anisotropic device pattern requires complicated epitaxy and etching processes, which limit scalable production and application. Here, solution-processed PEA2 MA4 (Sn0.5 Pb0.5 )5 I16 (PEA= phenylethylammonium, MA= methylammonium) polycrystalline film is probed as photoactive layer toward sensing polarized photon from 300 to 1050 nm. The growth of the PEA2 MA4 (Sn0.5 Pb0.5 )5 I16 crystal occurs in confined crystallographic orientation of the (202) facet upon the assistance of NH4 SCN and NH4 Cl, enhancing anisotropic photoelectric properties. Therefore, the photodetector achieves a polarization ratio of 0.41 and dichroism ratio (Imax /Imin ) of 2.4 at 900 nm. At 520 nm, the Imax /Imin even surpasses the one of the perovskite crystalline films, 1.8 and ≈1.2, respectively. It is worth noting that the superior figure-of-merits possess a response width of 900 kHz, Ion /Ioff ratio of ≈3 × 108 , linear dynamic range from 0.15 nW to 12 mW, noise current of 8.28 × 10-13 A × Hz-0.5 , and specific detectivity of 1.53 × 1012 Jones, which demonstrate high resolution and high speed for weak signal sensing and imaging. The proof of concept in polarized imaging confirms that the polarization-sensitive photodetector meets the requirements for practical application in target recognition.

High-Performance Perovskite Dual-Band Photodetectors for Potential Applications in Visible Light Communication.

Due to the rapid development of smart technology infusion, visible light communication (VLC) has been promising as a connection belt among real estates due to the appealing features including fast speed of data transmission and high bandwidth. Unfortunately, the issues of crosstalk, interference, or data leakage in the VLC impose rigorous requests for the receiver terminal, photodetector, including fast and accurate signal recognition, rapid decoding, etc. In pursuit of distinctive merits, a dual-band photodetector is proposed as an efficient receiver terminal for VLC in this work. With MAPbBr3 and MAPbI3 as photoactive layers, a device by stacking two photodiodes in opposite polarity is constructed to sense the signals at two different wavelengths from a commercial white light-emitting diode (LED) transmitter. By manipulating the applied bias direction, the response of a single device can be controllably switched between 300-570 and 630-800 nm with an optical crosstalk of less than -30 dB. The performance with an Ion/Ioff ratio of about 108, a response bandwidth (f-3dB) of ∼33 kHz, a response switching rate approaching 1000 Hz, and a detectivity of 1.75 × 1010 Jones ensures its application as an efficient data receiver. We believe that this work will provide the motivation to explore novel functional perovskite optoelectronic devices and put them to practical applications in the special field.

Sensitively switchable visible/infrared multispectral detection and imaging based on a tandem perovskite device.

Multispectral detection and imaging facilitate advances in target identification; for example, the switchable functionality of sensing visible photons and sensing near-infrared photons in the eyes of some vertebrate species provide visual sensitivity beyond the range of human vision. In this work, a single sensor device is constructed with stacking solution-processed MAPbI3 and MA0.5FA0.5Pb0.5Sn0.5I3 in opposite polarity for the multispectral detection of visible and NIR photons. With applied bias modulating built-in potential, the sensing response is tunable, while the good ambipolar carrier transport and high trap tolerance in perovskite films ensure high performance. As a result, the selective sensing toward visible photons from 350-800 nm and NIR photons from 700-1000 nm is achieved in a single photodetector under -0.3V and 0.5 V, respectively, with a high on/off ratio of ∼104, a relatively low optical crosstalk of -70 dB, and specific detectivity of over 1012 Jones. Moreover, the high mode-switching rate of 1000 Hz in altering the visible and NIR sensing mode and the high -3 dB bandwidth of ∼50 kHz enable our solution-processed perovskite-based multispectral photodetector to be recognized as an advanced technique for the fast and sensitive target multispectral imaging and identification.

Two-dimensional halide perovskite as ß-ray scintillator for nuclear radiation monitoring.

Ensuring nuclear safety has become of great significance as nuclear power is playing an increasingly important role in supplying worldwide electricity. ß-ray monitoring is a crucial method, but commercial organic scintillators for ß-ray detection suffer from high temperature failure and irradiation damage. Here, we report a type of ß-ray scintillator with good thermotolerance and irradiation hardness based on a two-dimensional halide perovskite. Comprehensive composition engineering and doping are carried out with the rationale elaborated. Consequently, effective ß-ray scintillation is obtained, the scintillator shows satisfactory thermal quenching and high decomposition temperature, no functionality decay or hysteresis is observed after an accumulated radiation dose of 10 kGy (dose rate 0.67 kGy h-1). Besides, the two-dimensional halide perovskite ß-ray scintillator also overcomes the notorious intrinsic water instability, and benefits from low-cost aqueous synthesis along with superior waterproofness, thus paving the way towards practical application.

Bionic Detectors Based on Low-Bandgap Inorganic Perovskite for Selective NIR-I Photon Detection and Imaging.

Fluorescence imaging with photodetectors (PDs) toward near-infrared I (NIR-I) photons (700-900 nm), the so-called "optical window" in organisms, has provided an important path for tracing biological processes in vivo. With both excitation photons and fluorescence photons in this narrow range, a stringent requirement arises that the fluorescence signal should be efficiently differentiated for effective sensing, which cannot be fulfilled by common PDs with a broadband response such as Si-based PDs. In this work, delicate optical microcavities are designed to develop a series of bionic PDs with selective response to NIR-I photons, the merits of a narrowband response with a full width at half maximum (FWHM) of <50 nm, and tunability to cover the NIR-I range are highlighted. Inorganic halide perovskite CsPb0.5 Sn0.5 I3 is chosen as the photoactive layer with comprehensive bandgap and film engineering. As a result, these bionic PDs offer a signal/noise ratio of ≈106 , a large bandwidth of 543 kHz and an ultralow detection limit of 0.33 nW. Meanwhile, the peak responsivity (R) and detectivity (D*) reach up to 270 mA W-1 and 5.4 × 1014 Jones, respectively. Finally, proof-of-concept NIR-I imaging using the PDs is demonstrated to show great promise in real-life application.

Intermediate phase-assisted solution preparation of two dimensional CsPbCl3 perovskite for efficient ultraviolet photodetection.

Fully-inorganic halide perovskites (HPs) have realized respectable progress in multiple optoelectronic applications. However, Cl-based fully-inorganic HPs that are ideal for ultraviolet (UV) photodetection applications in high demand still remain rarely explored mainly due to the poor solution processability compared with other counterparts. Here we propose a facile solution method to fabricate CsPbCl3 with not only high crystallinity but also a two dimensional (2D) morphology for efficient UV photodetection. 2D Ruddlesden-Popper perovskites (RPPs) are firstly prepared as the intermediate phase, which habitually grow into microplates owing to an intrinsic 2D structure. Then Cs+ was introduced in the form of highly soluble cesium acetate to exchange with the organic cations in the RPPs to produce 2D CsPbCl3 with preserved morphology and micron scale size. By this chemical route, the poor solubility issue can be addressed. All the procedures are conducted at room temperature in open air. The perfect band gap, high crystallinity and 2D morphology promise superior UV light sensing capability, one of the best overall performances featuring high responsivity, fast response speed, low driving voltages and good stability is obtained. This work is believed to fill in the "Cl-gap" for this promising class of material.