Dielectric ceramics possess a unique competitive advantage in electronic systems due to their high-power density and excellent reliability. Na 1/2 Bi 1/2 TiO 3 -based ceramics, one type of extensively studied energy storage dielectric, however, often experience A-site element volatilization and Ti 4+ reduction during high-temperature sintering. These issues may result in increased energy loss, reduced polarization and low dielectric breakdown electric field, ultimately making it challenging to achieve both high energy storage density and efficiency. To address these issues, we introduce a synergistic optimization strategy that combine polarization engineering and grain alignment engineering. First principles calculations and experimental analyses show that the doping of Mn 2+ can suppress the reduction of Ti 4+ in Na 1/2 Bi 1/2 TiO 3 -based ceramics and enhance ion off-centering displacements, thereby reducing energy loss and improving polarization. In addition, we prepared multilayer ceramic capacitors with grains oriented along the <111> direction using the template grain growth method. This approach effectively reduces electric-field-induced strain by 37% and markedly enhances breakdown electric field by 42% when compared with nontextured counterpart. As a result of this comprehensive strategy, <111 >-textured Na 1/2 Bi 1/2 TiO 3 -based multilayer ceramic capacitors achieve an ultra-high energy density of 15.7 J·cm −3 and an excellent efficiency beyond 95% at 850 kV·cm −1 , exhibiting a superior overall energy storage performance.
X-ray detection is vital in various fields such as medical imaging, security screening, and materials analysis. However, to meet the diverse detection requirements across different scenarios, current scintillators used for X-ray detection encounter challenges in both immediate and delayed radiation detections. In this work, flexibly controlling trap distribution through extra ions doping into Cs 2 NaTbCl 6 lead-free perovskites presents a promising avenue for addressing these challenges and advancing X-ray dose detection capabilities across diverse scientific domains. By doping Sb 3+ ions into the Cs 2 NaTbCl 6 host, the traps are significantly passivated through improved crystallinity, resulting in the suppression of afterglow behaviors and endowing the high-resolution real-time dynamic X-ray detection. Additionally, the incorporation of Mn 2+ into the Cs 2 NaTbCl 6 matrix causes significant lattice distortion, leading to increased concentrations of both shallow and deep traps, effectively boosting delayed X-ray detection efficiency. This work may provide an effective strategy for constructing efficient scintillators for the realization of multi-environmental X-ray imaging.
Kewei Ma,Yuhang Sheng,Guizhen Wang,Xiaowei Zhang,Yunsong Di,Cihui Liu,Liyan Yu,Lifeng Dong,Zhixing Gan
Mn 2+ doping has been developed to modulate the photoluminescence (PL) of CsPbCl 3 perovskite quantum dots (PQDs). However, the doped Mn 2+ may be expelled from the PQDs host with the long-term storing, resulting in inferior stability. Herein, CsPbCl 3 PQDs doped with different concentrations of Mn 2+ (Mn:CsPbCl 3 ) are prepared by a hot injection method. Our photostability tests reveal that when the doping concentration is <25%, or 40%–50%, the Mn 2+ doped PQDs are intrinsically stable. Anion exchange reactions are conducted between the stable CsPb 0.796 Mn 0.204 Cl 3 and CsPbBr 3 PQDs. Fluorescence color gamut of the resulting Mn:CsPb(Cl/Br) 3 PQDs almost covers the entire visible spectrum except for the deep red color. Benefiting from the intrinsic stability and wide color gamut, multicolor solid-state luminescence are acquired by incorporating the Mn:CsPb(Cl/Br) 3 PQDs in polymethyl methacrylate (PMMA) matrices, which are used as color converters for constructing light-emitting diodes (LEDs) with different colors.
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