Material-discriminating chromatic X-ray stationary intraoral computed tomography technology.

Three-dimensional (3D) dental imaging, such as cone-beam computed tomography (CBCT), is essential for diagnosing dental conditions but is limited by high costs, prolonged examination times, and increased radiation exposure. Additionally, standard CBCT lacks the ability to capture spectral X-ray information, which is crucial for distinguishing different dental materials. To address these issues, we propose a novel, to the best of our knowledge, low-cost, low-dose dental CT method, chromatic X-ray stationary intraoral computed tomography (S-IDECT), which integrates a multisource X-ray array with dual-energy CT technology.

Multienergy x-ray detection and imaging enabled by working voltage regulating unipolar carrier collection in perovskite detectors.

Multienergy x-ray imaging can provide additional substance information beyond morphology in conventional energy-integration imaging. The predominant approach, single photon counting, sets stringent requirements on low x-ray flux and signal discrimination and prolongs imaging time. Here, we report on the design of unipolar n-i-n perovskite detectors for multienergy x-ray imaging.

Synergistic Efficiency-Stability Enhancement in Sn-Pb Narrow-Bandgap Perovskite Solar Cells via Molecular Chain-Length Engineering.

Tin-lead (Sn-Pb) mixed narrow band gap (NBG) perovskite solar cells (PSCs) hold promise for tandem photovoltaic applications due to their tunable bandgap (≈1.25 eV), but face challenges from rapid crystallization kinetics and operational instability. Conventional ammonium salt passivators improve efficiency but often compromise stability by introducing mobile ions.

All-inorganic metafabric scintillators for conformally flexible and wearable x-ray detection and imaging.

Traditional scintillators rely on rigid inorganic matrices with high- elements, whose mechanical inflexibility restricts applications in multiple scenarios. Developing an efficient scintillator that combines inorganic properties with flexibility is a desirable yet highly challenging goal. We pioneered an inorganic metafabric scintillator paradigm through self-sustained slip system engineering, transforming brittle all-inorganic scintillation materials into ductile textile architectures, yielding intrinsically conformally flexible scintillators that adhere seamlessly to complex, curved surfaces.

Advances in Metal Halide Perovskite Scintillators for X-Ray Detection.

The relentless pursuit of advanced X-ray detection technologies has been significantly bolstered by the emergence of metal halides perovskites (MHPs) and their derivatives, which possess remarkable light yield and X-ray sensitivity. This comprehensive review delves into cutting-edge approaches for optimizing MHP scintillators performances by enhancing intrinsic physical properties and employing engineering radioluminescent (RL) light strategies, underscoring their potential for developing materials with superior high-resolution X-ray detection and imaging capabilities. We initially explore into recent research focused on strategies to effectively engineer the intrinsic physical properties of MHP scintillators, including light yield and response times.

3D laminar flow-assisted crystallization of perovskites for square meter-sized solar modules.

Transforming laboratory-scale perovskite solar cells to large-scale production will require uniform crystallization of the perovskite film. We designed a method to aid the crystallization process by generating well-defined three-dimensional (3D) laminar airflow over square meter-sized perovskite films using a customized 3D-printed structure. The resultant perovskite solar modules with areas of 0.

Efficient Perovskite/Organic Tandem Photovoltaic Devices and Large-area Modules Featuring Thick-Film Organic Solar Cells.

Perovskite-organic tandem solar cells (TSCs) possess significant potential due to their unique features, such as orthogonal processing solvents, tunable bandgap, and infinite molecular designs. However, their device performance is often hindered by the limited series current density, which is constrained by the absorption of the rear organic solar cell (OSC). Here, a fine-grained sub-cell matching model has been developed that enables rapid screening of material combinations based on practical sub-cell device parameters.

Stacked Scintillators Based Multispectral X-Ray Imaging Featuring Quantum-Cutting Perovskite Scintillators With 570 nm Absorption-Emission Shift.

Traditional energy-integration X-ray imaging systems rely on total X-ray intensity for image contrast, ignoring energy-specific information. Recently developed multilayer stacked scintillators have enabled multispectral, large-area flat-panel X-ray imaging (FPXI), enhancing material discrimination capabilities. However, increased layering can lead to mutual excitation, which may affect the accurate discrimination of X-ray energy.

Progress of Hole-Transport Layers in Mixed Sn-Pb Perovskite Solar Cells.

Hybrid organic-inorganic lead halide perovskite solar cells (PSCs) have rapidly emerged as a promising photovoltaic technology, with record efficiencies surpassing 26%, approaching the theoretical Shockley-Queisser limit. The advent of all-perovskite tandem solar cells (APTSCs), integrating Pb-based wide-bandgap (WBG) with mixed Sn-Pb narrow-bandgap (NBG) perovskites, presents a compelling pathway to surpass this limit. Despite recent innovations in hole transport layers (HTLs) that have significantly improved the efficiency and stability of lead-based PSCs, an effective HTL tailored for Sn-Pb NBG PSCs remains an unmet need.

Excited State Dynamics and Transport of Self-Trapped Excitons in Bi-Doped CsNaAgInBiCl Double Perovskites.

Lead-free double perovskites (DPs) have become notable in white light emission applications due to the self-trapped exciton (STE) formation in the excited state. However, the mechanism understanding of the excited state dynamics and transport of STE remains ambiguous. Here, we demonstrate a new STE (Bi-STE) forming in tiny Bi-doped CsNaAgInCl, alongside its intrinsic STE (i-STE), resulting in the DPs photoluminescence quantum yield (PLQY) increasing to as high as >90%.

Enhancing Efficiency of Large-Area Wide-Bandgap Perovskite Solar Modules with Spontaneously Formed Self-Assembled Monolayer Interfaces.

Wide-bandgap (WBG) perovskites play a crucial role in perovskite-based tandem cells. Despite recent advances using self-assembled monolayers (SAMs) to facilitate efficiency breakthroughs, achieving precise control over the deposition of such ultrathin layers remains a significant challenge for large-scale fabrication of WBG perovskite and, consequently, for the tandem modules. To address these challenges, we propose a facile method that integrates MeO-2PACz and Me-4PACz in optimal proportions (Mixed SAMs) into the perovskite precursor solution, enabling the simultaneous codeposition of WBG perovskite and SAMs.

Excitation-Selective and Double-Emissive Lead-Free Binary Hybrid Metal Halides for White Light-Emitting Diode and X-Ray Scintillation.

Zero-dimensional (0D) organic metal halides comprising heterogeneous metal cations in single phase can achieve multiple luminous emissions enabling them toward multifunctional light-emitting applications. Herein, A novel single crystal of (CHN)SbMnCl containing two luminescent centers of [SbCl] pentahedrons and [MnCl] tetrahedrons is reported. The large distance between Sb-Sb, Mn-Mn, and Sb-Mn as well as theory calculation indicate negligible interaction between individual centers, thus endowing (CHN)SbMnCl with excitation-dependable and efficient luminescence.

Quantitative Dual-Energy X-ray Imaging Based on K-Edge Absorption Difference.

Conventional flat panel X-ray imaging (FPXI) employs a single scintillator for X-ray conversion, which lacks energy spectrum information. The recent innovation of employing multilayer scintillators offers a route for multispectral X-ray imaging. However, the principles guiding optimal multilayer scintillator configuration selection and quantitative analysis models remain largely unexplored.

Bright Transparent Scintillators with High Fraction BaCl : Eu Nanocrystals Precipitation: An Ionic-Covalent Hybrid Network Strategy toward Superior X-Ray Imaging Glass-Ceramics.

Metal halide crystals are bright but hygroscopic scintillator materials that are widely used in X-ray imaging and detectors. Precipitating them in situ in glass to form glass ceramics (GCs) scintillator offers an efficient avenue for large-scale preparation, high spatial resolution, and excellent stability. However, precipitating a high fraction of metal halide nanocrystals in glass to maintain high light yield remains a challenge.

Enabling low-drift flexible perovskite photodetectors by electrical modulation for wearable health monitoring and weak light imaging.

Metal halide perovskites are promising for next-generation flexible photodetectors owing to their low-temperature solution processability, mechanical flexibility, and excellent photoelectric properties. However, the defects and notorious ion migration in polycrystalline metal halide perovskites often lead to high and unstable dark current, thus deteriorating their detection limit and long-term operations. Here, we propose an electrical field modulation strategy to significantly reduce the dark current of metal halide perovskites-based flexible photodetector more than 1000 times (from ~5 nA to ~5 pA).

Organic and Inorganic Metal Halide Tandem Scintillator for Dual-Energy Flat-Panel X-ray Imaging.

Traditional indirect flat-panel X-ray imaging (FPXI) uses inorganic scintillators with high-Z elements, which lack spectral information about X-ray photons and reflect only integrated X-ray intensity. To address this issue, we developed a stacked scintillator structure that combines organic and inorganic materials. This structure allows X-ray energies to be distinguished in a single shot by using a color or multispectral visible camera.

Long-Range Hot Charge Transfer Exciton Dissociation in an Organic/2D Semiconductor Hybrid Excitonic Heterostructure.

Whether and how an electron-hole pair at the donor-acceptor interface separates from their mutual Coulombic interaction has been a long-standing question for both fundamental interests and optoelectronic applications. This question is particularly interesting but yet to be unraveled in the emerging mixed-dimensional organic/2D semiconductor excitonic heterostructures where the Coulomb interaction is poorly screened. Here, by tracking the characteristic electroabsorption (Stark effect) signal from separated charges using transient absorption spectroscopy, we directly follow the electron-hole pair separation process in a model organic/2D heterostructure, vanadium oxide phthalocyanine/monolayer MoS.

Bifunctional Hole-Transport Materials with Modification and Passivation Effect for High-Performance Inverted Perovskite Solar Cells.

Hole-transport materials (HTMs) play an important role in perovskite solar cells (PSCs) to enhance the power conversion efficiency (PCE). The innovation of HTMs can increase the hole extraction ability and reduce interfacial recombination. Three organic small molecule HTMs with 4-cyclopenta[2,1-:3,4-']dithiophene (CPDT) as the central unit was designed and synthesized, namely, CPDTE-MTP (with the 2-ethylhexyl substituent and diphenylamine derivative end-group), CPDT-MTP (with the hexyl substituent and diphenylamine derivative end-group), and CPDT-PMTP (with the hexyl substituent and triphenylamine derivative end-group), which can form bifunctional and robust hole transport layer (HTL) on ITO and is tolerable to subsequent solvent and thermal processing.

Near-infrared absorbing acceptor with suppressed triplet exciton generation enabling high performance tandem organic solar cells.

Reducing the energy loss of sub-cells is critical for high performance tandem organic solar cells, while it is limited by the severe non-radiative voltage loss via the formation of non-emissive triplet excitons. Herein, we develop an ultra-narrow bandgap acceptor BTPSeV-4F through replacement of terminal thiophene by selenophene in the central fused ring of BTPSV-4F, for constructing efficient tandem organic solar cells. The selenophene substitution further decrease the optical bandgap of BTPSV-4F to 1.

Realizing nearly-zero dark current and ultrahigh signal-to-noise ratio perovskite X-ray detector and image array by dark-current-shunting strategy.

Although perovskite X-ray detectors have revealed promising properties, their dark currents are usually hundreds of times larger than the practical requirements. Here, we report a detector architecture with a unique shunting electrode working as a blanking unit to suppress dark current, and it theoretically can be reduced to zero. We experimentally fabricate the dark-current-shunting X-ray detector, which exhibits a record-low dark current of 51.

Accurate optical optimization of light-emitting diodes with consideration of coupling between Purcell factor and transmittance coefficient.

The calculation method for light emission efficiency splits external quantum efficiency (EQE) into internal quantum efficiency (IQE) and light extraction efficiency (LEE) independently. Consequently, the IQE connected to Purcell factor and the LEE are calculated separately. This traditional method ignores the interplays between the Purcell factor and transmittance coefficient in spectral domain, which all strongly depend on emitting directions.

Multispectral Large-Panel X-ray Imaging Enabled by Stacked Metal Halide Scintillators.

Conventional energy-integration black-white X-ray imaging lacks the spectral information of X-ray photons. Although X-ray spectra (energy) can be distinguished by the photon-counting technique typically with CdZnTe detectors, it is very challenging to be applied to large-area flat-panel X-ray imaging (FPXI). Herein, multilayer stacked scintillators of different X-ray absorption capabilities and scintillation spectra are designed; in this scenario, the X-ray energy can be discriminated by detecting the emission spectra of each scintillator; therefore, multispectral X-ray imaging can be easily obtained by color or multispectral visible-light camera in a single shot of X-rays.

Molecular Triplet Sensitization of Monolayer Semiconductors in 2D Organic/Inorganic Hybrid Heterostructures.

Hybrid heterostructures (HSs) comprising organic and two-dimensional (2D) monolayer semiconductors hold great promise for optoelectronic applications. So far, research efforts on organic/2D HSs have exclusively focused on coupling directly photoexcited singlets to monolayer semiconductors. It remains unexplored whether and how the optically dark triplets in organic semiconductors with intriguing properties (e.

Solution-Processed Perovskite/Metal-Oxide Hybrid X-Ray Detector and Array with Decoupled Electronic and Ionic Transport Pathways.

Lead halide perovskites possess heavy elements and excellent mobility-lifetime (µτ) product, becoming desirable candidates for X-ray detectors. However, current perovskite photoconduction detectors (PCDs) with vertical geometry, where electronic signals and mobile ions share the same conduction path, are facing with extremely challenging ion-migration issue. Herein, a hybrid X-ray detector device structure, in which perovskite is vertically stacked onto an indium oxide (In O ) transistor with lateral transport geometry is designed, perovskite mainly acts as X-ray sensitizer to activate In O conduction channel, the actual electrical signal is conducted and collected in the lateral metal-oxide device.

Top-Emitting Microcavity Light-Emitting Diodes Based on All-Thermally Evaporated Lead-Free Copper Halide Self-Trapped-Exciton Emitters.

Lead-free metal halide light-emitting diodes (LEDs) based on cesium copper halide (CsCuI) self-trapped-exciton (STE) emissions show great potential in lighting and color display applications, especially because of their nontoxicity and earth abundance. However, so far, the efficiency and color purity of CsCuI-based LEDs remain low. Here we demonstrate the emission of a CsCuI emitter can be enhanced and narrowed in a top-emitting microcavity device.