Lead-Free Perovskite With Efficient Tellurium Ion Activation for Multifunctional Applications.

Lead-free perovskite materials have received extensive attention due to their non-toxicity, super environmental stability and adjustable photoelectric properties. However, the inherent problems of low luminous efficiency and low photoluminescence quantum yields (PLQYs) limit its development in multifunctional applications. Here, Te4+ doped Cs2ZrCl6 with high luminous efficiency and stability for multifunctional applications are developed. Te4+ ions are used as emission centers to improve the optical properties of Cs2ZrCl6 to make efficient and stable single-component white light-emitting diodes (WLEDs), and can be used as scintillator materials to improve scintillation performance to achieve high-resolution and low-dose X-ray imaging detection. In addition, it is found for the first time that Te4+ ions can be introduced into the trap center, so that the Cs2ZrCl6:Te4+ perovskite material exhibits excellent persistent luminescence (PersL) and mechanoluminescence (ML) after X-ray radiation, which has potential applications in the fields of delayed imaging and stress sensing. This work provides a method for designing lead-free perovskites with high optical performance and scintillating properties, as well as developing multifunctional applications.

Customizable Scintillator of Cs3 Cu2 I5 :2% In+ @Paper for Large-Area X-Ray Imaging.

High-resolution X-ray imaging is increasingly required for medical diagnosis and large-area detection. However, the issues of scattering and optical crosstalk are limiting the spatial resolution of the indirect X-ray imaging. In this study, a feasible and efficient strategy is proposed to in situ synthesize flexible Cs3 Cu2 I5 :2%In+ @paper as a superior scintillator film, which can be scaled up to an ultra-large area of 4800 cm2 . The as-obtained Cs3 Cu2 I5 :2%In+ @paper performs a fascinating photoluminescence quantum efficiency up to 88.14%, a steady state light yield of 70169 photons/MeV, and spatial resolution of 15 lp mm-1 . Moreover, the suppressed physical scattering and optical crosstalk of the corresponding film are demonstrated. Accordingly, this work explores a feasible fabrication of customizable scintillation films with large area for high-resolution X-ray detection.

High Thermal Stability of Copper-Based Perovskite Scintillators for High-Temperature X-ray Detection.

High-temperature scintillation detectors play a significant role in oil exploration. However, traditional scintillators have limited ability to meet the requirements of practical applications owing to their low thermal stability. In this study, we designed and developed a one-dimensional (1D) Cs5Cu3Cl6I2 scintillator with high thermal stability. In addition, by preparing Cs5Cu3Cl7I, we proved that the Cs5Cu3Cl6I2 scintillator exhibits high thermal stability because the bridges linking the structural units in the 1D chain structure are only formed by I- ions, which improve their structural rigidity. The scintillator has a high steady-state light yield (59,700 photons MeV-1) and exhibits the highest spatial resolution for powder-based scintillation screens (18 lp mm-1) after cyclic treatment within the temperature range of 298-423 K. The Cs5Cu3Cl6I2 scintillator allows the visualization of alloy melting, indicating that it has significant potential for application in high-temperature environments. This study provides a new perspective toward the design of scintillators with high thermal stability.

Visualization of X-rays with an Ultralow Detection Limit via Zero-Dimensional Perovskite Scintillators.

X-rays play an extremely significant role in medical diagnosis, safety testing, scientific research, and other practical applications. However, as the main sources of radioactive pollution, the hazard of X-rays to human health and the environment has been a major concern. Herein, the explored perovskite scintillator of Cs2Zr1-xPbxCl6 in this work exhibits an ultrahigh radioluminescence intensity owing to the enhanced X-ray absorption for the introduction of Pb2+ ions. The Cs2Zr1-xPbxCl6 crystals are demonstrated as efficient scintillators with a self-trapped exciton emission and extremely high steady-state light yield (∼101,944 photons meV-1). This fascinating scintillator provides a convenient visual tool for X-ray detection even for an indoor lighting environment, reaching a low detection limit of ∼14.2 nGy·s-1, which is about 1/387 of the typical medical imaging dose (5.5 µGy·s-1). Moreover, X-ray imaging with a high resolution of 16.6 lp·mm-1 is achieved with the as-explored Cs2Zr1-xPbxCl6 scintillator film. Herein, the Cs2Zr1-xPbxCl6 scintillator provides a feasible strategy for X-ray monitoring in the field of biomedicine, high-energy physics, national security, and other applications.

Structure-activity relationship of 39 analogs of laetispicine with antidepressant properties.

The natural product Laetispicine ( N -isobutyl-(3,4-methylendioxyphenyl)-2E, 4E, 9E-undecatrienoamide), was isolated from the Piper laetispicum C. DC and screened, for its antidepressant activity and antinociceptive effects. Structure-functional activities of five natural products indicated that biological activity is dependent on double bonds present within the benzene ring and a conjugated double bond located at positions 2-3 and 4-5 in the molecular structure. To further understand the structural-activity relationship of Laetispicine as a new potent and safe antidepressant, the structural-activity relationship of 39 analogs of Laetispicine were synthetized and tested in forced swimming tests in mice whilst also in protective effects against glutamate or H 2 O 2 induced apoptosis in PC12 cells. The results show that the compound 30 - N -isobutyl-11-(4-chlorophenyl) undeca-2E,4E,9E-trienamide exhibited the same activity as the parental compound Laetispicine, and furthermore, the effective dose of this compound is lower than Laetispicine. Therefore, the compound 30 might be a potentially useful therapy in the treatment of depression. For structure, the conjugated double bonds located at 2-3, 4-5 and isolated double bonds from benzene ring are necessary for the antidepressant activities no matter the different length of carbon chain; the isobutyl connected with acylamino also are necessary; and the benzodioxole moiety is replaceable, the halogen atom in phenyl ring at the para-position could enhance this kind of activity.

Total synthesis and antidepressant activities of laetispicine and its derivatives.

The first total synthesis of laetispicine (1a), an amide alkaloid isolated from the stems of Piper laetispicum C.DC (Piperaceae), and the synthesis of some of its derivatives were described. Based on the evaluation of antidepressant activities in the forced swimming test, compounds 1h and 1i were identified as potent and safe antidepressant lead compounds.