0D manganese-based X-ray scintillators have garnered significant attention due to their unique ion-centered luminescence and high photoluminescence quantum yields (PLQYs). However, achieving a synergistic optimization among light yield, detection limit, spatial resolution, and non-planar imaging capability remains a challenge. In this study, single crystals of (C25H22P)2MnBr4 are synthesized via a solvent evaporation method. Owing to the tetrahedral coordination geometry of the [MnBr4]2- polyhedron and the characteristics of the d-d electron transition of Mn2+, the as-prepared materials exhibit a strong green emission at 512 nm with a high PLQY of 91.27%. Furthermore, flexible (C25H22P)2MnBr4@PDMS scintillators are fabricated via a template assembly method. Benefiting from high optical transparency and excellent luminescent properties, the scintillators demonstrate outstanding radiative performance, achieving a maximum light yield of up to 48750 ph/MeV, a low detection limit of 45.8 nGyair/s, and a high spatial resolution of 17.64 lp/mm. Notably, the flexible scintillators are capable of realizing both planar and non-planar X-ray imaging with high quality, thereby offering a versatile and effective platform for high-performance X-ray visualization.

In this paper, we describe an eight-electrode vector network analyzer (VNA) testbed for the characterization of MEMS vibration ring gyroscopes. The testbed is meant to provide a preliminary yet accurate assessment of gyroscopic figures of merit ahead of the full design and implementation of drive and sensing circuits. The testbed is operated under vacuum and is used to characterize a novel inward-oriented, high-compliance, vibrating-ring gyroscope fabricated in the low-cost four-layer MEMSCAP SOIMUMPS process. Modal measurements and device simulations are within 0.5% of each other.

Doping carbon materials with heteroatoms can enhance the performance of capacitive desalination (CDI). However, this process may also alter the surface charge of the electrode. This study employs N/P doped carbon materials dispersed with atomic scale iron (Fe) to regulate the surface charge of the electrode (Fe-N/P-C). Subsequently, an asymmetric capacitive deionization electrode is assembled to facilitate the complete adsorption of both cations and anions from a CuCl2 solution. Experimental results indicated that the adsorption capacity reached 490.3 mg/g at a concentration of 500 mg/L and a voltage of 1.8 V. This research integrates the tailoring of surface charge properties with the optimization of asymmetric electrodes, offering novel insights for applications in CDI and related fields.

Flexible scintillator screens with high stability and spatial resolution are essential for X-ray imaging applications. 0D organic-inorganic antimony halides have emerged as promising candidates owing to their superior optical properties and facile synthesis. In this study, high-quality C21H20OPSbCl4 single crystals incorporating dimeric [Sb2Cl8]2- units are synthesized via an evaporation crystallization method. These crystals exhibit intense yellow emission with a photoluminescence quantum yield (PLQY) of 92%. Furthermore, large-area and flexible C21H20OPSbCl4@PMMA scintillator films are fabricated via a template assembly method, achieving a light yield of 26880 photons/MeV, a detection limit of 160 nGyair/s, and a spatial resolution of up to 12.3 lp/mm. These films exhibit excellent mechanical robustness and retain high-resolution X-ray imaging performance even under repeated bending, thereby enabling effective imaging of non-planar objects. These scintillators further demonstrate remarkable stability under light, thermal, and X-ray irradiation. This study highlights the promise of organic-inorganic antimony halides as a platform for developing high-performance flexible scintillators for advanced X-ray detection.

High-quality perovskite films with vertical orientation and compact bottom interface are critical for the design and engineering of efficient and stable Cs(x)FA(1-x)PbI(3)-based perovskite solar cells (PSCs). Herein, a robust amidino-based ligand, namely morpholine-4-carboximidamide hydrochloride (M4CH), is introduced into the perovskite precursor to fabricate (001)-dominated perovskite films and simultaneously regulate buried interfacial morphologies and energetics. M4CH enables vertically oriented growth via its strongest adsorption energy on perovskite (001) facets. Concurrently, M4CH accumulates at the buried interface, forming a positive dipole layer to enhance carrier extraction. The resulting inverted methylammonium (MA)-free PSC achieves a champion power conversion efficiency (PCE) of 24.52%, an exceptionally high open-circuit voltage (V-OC) of 1.181 V, and outstanding thermal and environmental stability. Encouragingly, the M4CH-incorporated module, with an aperture of 642 cm(2), demonstrates an impressive efficiency of 18.54% (certified 18.48%), positioning it among the highest efficiencies recorded for large-scale inverted perovskite solar modules (PSMs).

Engineering of interface phonons is of vital importance to achieve extremely low thermal conducting candidates, which are crucial for energy conversion devices. Here, we reported an ultralow lattice thermal conductivity (0.173 W m-1 K-1) across the all-inorganic halide perovskite CsSnBr3/Cs2SnBr6 interface based on large-scale atomic molecular dynamics simulations. Accurate neuroevolution potential derived from ab initio density functional theory was employed to reveal the enhanced anharmonicity and phonon scattering/localization that contribute to the low lattice thermal transport capability. A strong mixed phonon liquid character and nonlinear interface density dependent thermal conductivity have been observed for the CsSnBr3/Cs2SnBr6 interface. The insights obtained from our findings might provide an efficient way to design crystalline anisotropic thermoelectric materials.

Metal halide perovskites are the most promising candidates in the field of X-ray detection and imaging. However, the self-absorption and toxicity of lead-based perovskites severely limit their widespread application. Herein, zirconium-based halide perovskites have attracted much attention due to their excellent stability, low toxicity, and suitable bandgap, self-free absorption, wide emission spectrum. In this work, (C8H20N)2ZrCl6 single crystals are synthesized by evaporation crystallization, which presents a large Stokes shift of 203 nm, a high PLQY of 80.77%, and good stability over 180 days. Then, the assembled (C8H20N)2ZrCl6@PDMS films show good flexibility (bending and stretching) and a spatial resolution of 5.8 lp/mm. Thus, this work not only provides a route to explore lead-free metal halide perovskites with broadband emission but also demonstrates flexible zirconium-based scintillators for X-ray scintillation imaging.

The small size and large trap density have seriously hindered the application of cesium copper iodine single crystals (SCs). Herein, we propose a strategy for synthesizing high-quality and large-sized CsCu2I3 SCs by gradient crystallization. The as-synthesized CsCu2I3 SCs exhibit a large length of 1.7 cm with a low trap density of 4.17 × 109 cm−3. Moreover, such CsCu2I3 SCs show excellent photoelectric response to ultraviolet (UV) irradiation, owing to their high absorption coefficient, large Stokes shift, and one-dimensional electronic structure. The measured responsivity and detectivity of the CsCu2I3 SC-based photodetectors reach the maxima of 24.58 A/W and 1.02 × 1013 Jones, respectively, under 365 nm light irradiation. Due to the outstanding UV detection performance, such photodetectors are also utilized for achieving direct UV imaging with high resolutions.

In this report, the effect of A-site cations on the lattice thermal conductivity (kappa L) of nitride perovskites was comparatively studied by first-principles calculations in similar crystal structures, LaWN3 and YWN3. The A-site cation is found to induce notable differences in acoustic (0-125 cm-1) and low-lying optical phonons (125-500 cm-1), which translate into a large kappa L discrepancy (around 20%). It is worth mentioning that the higher kappa L of LaWN3 is contributed mostly by atom N in the [WN6] octahedron, although the average W-N bond length is almost identical for LaWN3 and YWN3. Faster group velocity, longer lifetime, and larger Gruneisen parameters in optical branches are observed in LaWN3, which should be ascribed to the longer distance between the cation La and the [WN6] octahedron. Our findings provide a deep understanding of the role of the A-site cation in the thermal conductivity of nitride perovskites.

Quasi-two-dimensional (quasi-2D) perovskites have attracted much attention due to their outstanding properties, such as inherent quantum-well structure, strong dielectric and quantum confinement, large exciton binding energy, and high photoluminescence quantum yield. By virtue of these superior merits, quasi-2D perovskites have shown great potential for next-generation light-emitting diodes (LEDs). Herein, this review presents an overview of the basic properties of quasi-2D perovskites and their photoluminescence modulations by large organic cation engineering, monovalent cation engineering, halogen engineering, defect passivation engineering, and dimensionality engineering. Furthermore, the strategies of charge-transport layer optimization, interfacial engineering, light-outcoupling efficiency improvement, and operating stability improvement are summarized for fabricating high-performance quasi-2D perovskite LEDs (PeLEDs). Finally, the challenges and outlook for the future development of quasi-2D PeLEDs are unambiguously proposed.

Abstract The bidirectional migration of halides and silver causes irreversible chemical corrosion to the electrodes and perovskite layer, affecting long-term operation stability of perovskite solar cells. Here we propose a silver coordination-induced n-doping of [6,6]-phenyl-C61-butyric acid methyl ester strategy to safeguard Ag electrode against corrosion and impede the migration of iodine within the PSCs. Meanwhile, the coordination between DCBP and silver induces n-doping in the PCBM layer, accelerating electron extraction from the perovskite layer. The resultant PSCs demonstrate an efficiency of 26.03% (certified 25.51%) with a minimal non-radiative voltage loss of 126 mV. The PCE of resulting devices retain 95% of their initial value after 2500 h of continuous maximum power point tracking under one-sun irradiation, and > 90% of their initial value even after 1500 h of accelerated aging at 85 °C and 85% relative humidity.

The instability of top interface induced by interfacial defects and residual tensile strain hinders the realization of long-term stable n-i-p regular perovskite solar cells (PSCs). Herein, one molecular locking strategy is reported to stabilize top interface by adopting polydentate ligand green biomaterial 2-deoxy-2,2-difluoro-d-erythro-pentafuranous-1-ulose-3,5-dibenzoate (DDPUD) to manipulate the surface and grain boundaries of perovskite films. Both experimental and theoretical evidence collectively uncover that the uncoordinated Pb2+ ions, halide vacancy, and/or I─Pb antisite defects can be effectively healed and locked by firm chemical anchoring on the surface of perovskite films. The ingenious polydentate ligand chelating is translated into reduced interfacial defects, increased carrier lifetimes, released interfacial stress, and enhanced moisture resistance, which should be liable for strengthened top interface stability and inhibited interfacial nonradiative recombination. The universality of the molecular locking strategy is certified by employing different perovskite compositions. The DDPUD modification achieves an enhanced power conversion efficiency (PCE) of 23.17-24.47%, which is one of the highest PCEs ever reported for the devices prepared in ambient air. The unsealed DDPUD-modified devices maintain 98.18% and 88.10% of their initial PCEs after more than 3000 h under a relative humidity of 10-20% and after 1728 h at 65 °C, respectively.

The NiOx/perovskite interface in NiOx-based inverted perovskite solar cells (PSCs) is one of the main issues that restrict device performance and long-term stability, as the unwanted interfacial defects and undesirable redox reactions cause severe interfacial non-radiative recombination and open-circuit voltage (Voc) loss. Herein, a series of self-assembled molecules (SAMs) are employed to bind, bridge, and stabilize the NiOx/perovskite interface by regulating the electrostatic potential. Based on systematically theoretical and experimental studies, 4-pyrazolecarboxylic acid (4-PCA) is proven as an efficient molecule to simultaneously passivate the NiOx and perovskite surface traps, release the interfacial tensile stress as well as quench the detrimental interface redox reactions, thus effectively suppressing the interfacial non-radiative recombination and enhancing the quality of perovskite crystals. Consequently, the PSCs with 4-PCA treatment exhibited an eminently increased Voc, leading to a significant increase in power conversion efficiency from 21.28% to 23.77%. Furthermore, the unencapsulated devices maintain 92.6% and 81.3% of their initial PCEs after storing in air with a relative humidity of 20%-30% for 1000 h and heating at 65 °C for 500 h in a N2-filled glovebox, respectively.

The migration and diffusion of Li+ and halide ions, as well as the volatilization of 4-tert butylpyridine (tBP), seriously restrain the long-term operational stability of n-i-p perovskite solar cells (PSCs). Herein, we employ l-glutamic acid dibenzyl ester 4-toluenesulfonate (GADET) to simultaneously modulate the hole transport layer (HTL) and buried interface, which stabilizes the HTL and minimizes interfacial energy loss by immobilizing Li+, tBP, and halide ions and passivating dual interface defects. After forming Spiro-OMeTAD(center dot+)TFSI(-), GADET impedes the Li+ ion diffusion through the ionic bond interaction of P-methylbenzenesulfonate anion and Li+, while the formation of the hydrogen bond of -NH3+ with tBP can suppress the volatilization of tBP. Moreover, the halide ion migration and interfacial trap-induced nonradiative recombination are inhibited via passivating undercoordinated Pb and halide vacancy defects based on multiple chemical bonds. The synergistically modified devices achieve a champion efficiency of 25.06% (certified PCE of 24.08%). Meanwhile, the stability of PSCs was significantly improved.

Electron-phonon and electron-hole interactions have played a central role in the transport and optoelectronic properties of lead-free vacancy-ordered double perovskites (VODPs). In this report, state-of-the-art first-principle calculations were employed to study the polaron and exciton in Cs2SnBr6. Electron polaron and hole polaron were found to be small (1-2 lattice units) with a large formation energy of >4 eV. The Sn-Br bond length within the [SnBr6] octahedra was elongated (shrunk) by 3.5% (0.5%) as one electron (hole) was added. Furthermore, the exciton with a binding energy of 250 meV and a size of similar to 5 lattice units was identified. Our study provides a key picture to understand the intrinsic optoelectronic properties of VODP Cs2SnBr6, which is vital to designing efficient light emission materials in the future.

Ion migration-induced intrinsic instability and large-area fabrication pose a tough challenge for the commercial deployment of perovskite photovoltaics. Herein, an interface heterojunction and metal electrode stabilization strategy is developed by suppressing ion migration via managing lead-based imperfections. After screening a series of cations and nonhalide anions, the ideal organic salt molecule dimethylammonium trifluoroacetate (DMATFA) consisting of dimethylammonium (DMA+) cation and trifluoroacetate (TFA-) anion is selected to manipulate the surface of perovskite films. DMA+ enables the conversion of active excess and/or unreacted PbI2 into stable new phase DMAPbI3, inhibiting photodecomposition of PbI2 and ion migration. Meanwhile, TFA- can suppress iodide ion migration through passivating undercoordinated Pb2+ and/or iodide vacancies. DMA+ and TFA- synergistically stabilize the heterojunction interface and silver electrode. The DMATFA-treated inverted perovskite solar cells and modules achieve a maximum efficiency of 25.03% (certified 24.65%, 0.1 cm2) and 20.58% (63.74 cm2), respectively, which is the record efficiency ever reported for the devices based on vacuum flash evaporation technology. The DMATFA modification results in outstanding operational stability, as evidenced by maintaining 91% of its original efficiency after 1520 h of maximum power point continuous tracking.

Low-dimensional hybrid organic-inorganic metal halides (OIMHs) have attracted considerable attention in anti-counterfeiting due to their non-toxicity and high photoluminescence quantum yield (PLQY). However, many reported OIMHs are either not reversible or have a poor PLQY. In this study, two antimony-based halides, (C21H21P)2SbCl5 and (C22H24P)2SbCl5, are synthesized using different organic cations. Both compounds exhibit bright orange-yellow emissions with a PLQY of 82.6% and 83.5%, respectively. The orange-yellow emission of (C21H21P)2SbCl5 and (C22H24P)2SbCl5 are attributed to the radiative recombination of self-trapping excitons. While (C21H21P)2SbCl5 maintains stable orange-yellow luminescence when exposed to ethanol, (C22H24P)2SbCl5 undergoes a structural transformation to non-luminescent (C22H24P)2Sb2Cl8 upon ethanol treatment, which can be reverted to its luminescent state by heating. Even after multiple cycles, the PLQY of (C22H24P)2SbCl5 is still over 80%, demonstrating excellent cycling stability. (C21H21P)2SbCl5 and (C22H24P)2SbCl5 are also explored as fluorescent materials for Morse code anti-counterfeiting and optical logic gate applications. This work offers a completely new option for fluorescent material used for security information.

The instability of the buried interface poses a serious challenge for commercializing perovskite photovoltaic technology. Herein, we report a polydentate ligand reinforced chelating strategy to strengthen the stability of buried interface by managing interfacial defects and stress. The bis(2,2,2-trifluoroethyl) (methoxycarbonylmethyl)phosphonate (BTP) is employed to manipulate the buried interface. The C=O, P=O and two −CF 3 functional groups in BTP synergistically passivate the defects from the surface of SnO 2 and the bottom surface of the perovskite layer. Moreover, The BTP modification contributes to mitigated interfacial residual tensile stress, promoted perovskite crystallization, and reduced interfacial energy barrier. The multidentate ligand modulation strategy is appropriate for different perovskite compositions. Due to much reduced nonradiative recombination and heightened interface contact, the device with BTP yields a promising power conversion efficiency (PCE) of 24.63 %, which is one of the highest efficiencies ever reported for devices fabricated in the air environment. The unencapsulated BTP-modified devices degrade to 98.6 % and 84.2 % of their initial PCE values after over 3000 h of aging in the ambient environment and after 1728 h of thermal stress, respectively. This work provides insights into strengthening the stability of the buried interface by engineering multidentate chelating ligand molecules.

Long-term stability and power conversion efficiency of perovskite solar cells are strongly affected by their precursor compositions and intermediate phases during the fabrication process. In general, complex chemical reactions happen in a short time scale during the nucleation and crystal growth steps. However, the ex-situ characterization probes cannot capture the dynamics of perovskite film formation and degradation. In this review, we discussed the ambient air-compatible in-situ characterization probes that are used to monitor the evolution of the structural, morphological, and optoelectronic properties of perovskite films, which provides a deep understanding of the perovskite crystal formation process.

Interfacial defects result in serious carrier nonradiative recombination. The correlation between spatial conformation of modifiers and interfacial carrier dynamics is scarcely revealed. Here, an effective interfacial carrier dynamics and defect passivation modulation strategy via controlling spatial conformation of modification molecules is reported. Two kinds of similar Lewis base ligand molecules, biuret (BU) and dithiobiuret (DTBU), are employed to modify the surface of perovskite films. BU and DTBU can effectively passivate interfacial defects but the former is more effective than the latter on account of higher electronegativity and more advantageous molecular spatial arrangement. The planar symmetrical BU molecules can arrange compactly and orderly on the surface of perovskite films while the adsorbed DTBU molecules with a twisted asymmetrical structure are relatively chaotic. BU modification reduces interfacial energy offset, ameliorates improved interfacial energy band alignment, and speeds up hole extraction. In contrast, a much thicker adsorbed layer is yielded after DTBU treatment, which impedes carrier extraction and transfer and accordingly leads to grievous nonradiative recombination. The spatial conformation difference produces an inverse influence on device performance (positive for BU and negative for DTBU). The power conversion efficiency is much enhanced from 21.66% to 23.54% after BU modification along with improved stability.