Search

While SnF2 is reported as an effective additive for improving the efficiency of lead-free tin-based perovskite solar cells, the mechanism is still unclear and requires further studies. Upon incorporating SnF2 into MASnI3, SnF2 reduces the intrinsic carrier density from 1018 to 1012 cm–3 and produces a longer carrier diffusion length as confirmed by the Hall measurements. The femtosecond transient absorption spectroscopy shows that SnF2 doping enhances the hot-phonon bottleneck effect of MASnI3. The slow cooling process of hot carriers may help to reduce non-radiative recombination, increase the fluorescence lifetime, and, therefore, improve the utilization rate of carriers. Finally, lead-free low bandgap perovskite MASnI3 is utilized as a light absorbing layer in solar cells, achieving high optical current and high voltage in tin-based perovskite solar cells. The final power conversion efficiency is 10.2%, while the power conversion efficiency for the control unit is 6.69%. [ABSTRACT FROM AUTHOR]

Perovskite light‐emitting devices (PeLEDs) have emerged as a highly promising contender for the next generation of lighting and display technologies. During the nucleation and crystallization process, numerous defects are commonly formed on the surface and grain boundaries as a result of the ionic characteristics of perovskite, especially in an air environment. These defects ultimately contribute to the deterioration of the photoelectron properties. In this study, CsPbI3 nanocrystals (NCs) solution is introduced into ethyl acetate antisolvent as an additive, resulting in the high‐quality perovskite films under ambient conditions. The introduction of CsPbI3 NCs has been found to increase the grain size and improve the uniformity of perovskite films while also effectively passivating defects. More significantly, the utilization of CsPbI3 NCs leads to the formation of a 0D/3D local heterojunction that is distributed throughout the MAPbI3 film. These distributed heterojunctions significantly increase both the carrier concentration and the photoluminescence performance. With the incorporation of doped perovskite films, Silicon (Si) ‐based PeLEDs demonstrate enhanced efficiency, achieving a maximum external quantum efficiency of 12.6% in ambient conditions. Additionally, these devices exhibit a prolonged operational half‐life of 80 minutes. This study presents a novel methodology for fabricating high‐efficiency Si‐based PeLEDs that exhibit exceptional electroluminescence characteristics. [ABSTRACT FROM AUTHOR]

For the traditional surface acoustic wave (SAW) devices, its RF performance is mainly determined by the micro-nano processing technology of the electrode and the physical properties of the piezoelectric material itself. As a ferroelectric material and piezoelectric material, LiNbO3 has high piezoelectric properties and electromechanical coupling coefficient, which has been widely concerned by researchers. LiNbO3 films with different thicknesses were epitaxially grown on Al2O3 (001) substrates by pulsed laser deposition (PLD). The SAW velocity of the film is increased by stress adjustment, and the SAW device obtains a higher response frequency. The stress on the surface of the film decreases with the increase of the film thickness, which reduces the velocity of the surface acoustic wave. The piezoelectric film prepared by PLD technology has the advantage of epitaxial stress regulation. The SAW velocity of LiNbO3 film can reach 5701.2 m/s, and the piezoelectric coefficient d33 = 17.6 pm/V. It is an effective way to improve the RF performance of SAW devices. In addition, the SAW device has the best performance when the electrode duty cycle is 50%. [ABSTRACT FROM AUTHOR]

High entropy materials have garnered considerable attention recently as a class of materials with intricate stoichiometry, exhibiting high levels of entropy. These materials hold great promise as candidates for electrochemical energy storage devices due to their ideal regulation, good mechanical and physical properties and attractive synergy effects of multi‐elements. In this perspective, we provide an overview of high entropy materials used as anodes, cathodes, and electrolytes in rechargeable batteries, with insight into the materials' structure‐property relationship and the influence on battery performance. Additionally, we offer insights into the future perspectives of high entropy materials, emphasizing their crucial role in next‐generation batteries. [ABSTRACT FROM AUTHOR]

In this work, we report the effectively enhanced tunneling electroresistance effect in Au/(SrTiO3)2/(BaTiO3)4/(CaTiO3)2/Nb:SrTiO3 superlattice ferroelectric tunnel junction (FTJ). The stable polarization switching and enhanced ferroelectricity were achieved in the nanoscale thickness high-quality epitaxial superlattice. A high ON/OFF current ratio of more than 105 was obtained at room temperature, which is an order of magnitude larger than the BaTiO3 FTJ with the same structure. Nonvolatile resistance switching controlled by nonvolatile polarization switching was observed in the superlattice FTJ. Driven by increased polarization and intrinsic asymmetric ferroelectricity, a highly asymmetric depolarization field is generated compared with the Au/BaTiO3/Nb:SrTiO3 FTJ, resulting in an enhanced tunneling electroresistance effect. These results provide a potential way to construct FTJ memory devices by constructing asymmetric three-component ferroelectric superlattices. [ABSTRACT FROM AUTHOR]

In this work, we demonstrated the large-area film growth of all-inorganic perovskite CsPbBr3 with semiconductor industry compatible radio frequency magneton sputtering technology. This approach avoids the use of toxic organic solvents, which are required extensively for the solution growth process of these perovskite films. Even on ordinary glass substrates, the CsPbBr3 film of 100 cm2 with a single phase and ultra-smooth surface can be grown under optimized sputtering conditions, among which the substrate temperature is proved very important. Temperature-dependent photoluminescence spectra and femtosecond transient absorption spectra studies show that no subband defect levels are observed in such perovskite films. The temperature-dependent resistivity measurement exhibits a typical thermally activated electrical behavior, and a bandgap of 2.24 eV is obtained, which is consistent with the optical measurements. Therefore, both the optical and electrical studies indicate that the CsPbBr3 film with high optical quality can be grown with effective one-step sputtering technology. [ABSTRACT FROM AUTHOR]