A pre-embedding mixed A-cation halide strategy is developed to eliminate the residual unstable PbI₂ and lattice strain near the buried interface of the perovskite layer for the stability improvement of formamidinium-based perovskite solar cells.

In this Letter, we present a cylindrical conformal holographic impedance metasurface for orbital angular momentum (OAM) generation. The conformal holographic metasurface is designed by establishing the element library and deducing the formula of holographic tensor impedance modulation. The feasibility of the scheme is verified by simulations and experiments. Simulated and experimental results are in good agreement with theoretical analysis. The results show that OAM vortex wave energy can be generated efficiently by a cylindrical conformal impedance metasurface, which can provide a reference for OAM communication and vortex radars with conformal devices.

A harmonic suppressed (HS) frequency selective rasorber (FSR) based on square loops resonators and resistive-film sheets is presented in this paper. The frequency selective rasorber is designed by cascading the band pass FSS and broadband absorber together which owns a main pass band at center frequency of 8GHz, with harmonic transmission windows suppressed and out-of-band reflection absorbed from 12GHz to 26GHz. Lossless FSS with band pass response and lossy absorber with broadband absorption are analyzed by equivalent circuit model respectively. The frequency range of harmonic suppression covers three octaves of main pass band frequency. Besides, the measured results agree well with the simulated ones. The proposed harmonic suppressed FSR could be used as radome in enhancing anti-interference performance of wireless communication system and improving stealth performance of radar platform.

The phenomenon of asymmetric transmission (AT) means the existence of a giant difference in transmittance after the incident waves pass through the special slab in two opposite directions, which is quite useful for realizing irreversible electromagnetic waves and has attracted much attention in recent years. However, it is difficult to achieve wideband asymmetric transmission and linear polarization conversion simultaneously using the bilayer transmission-mode structure. In this work, we propose and numerically investigate a high-efficiency transmission-mode metamaterial that consists of twisted multigap rings on both sides of a dielectric slab. Benefiting from the antisymmetric design of the split ring bilayer transmitarray element, the proposed structure excites the electric and magnetic dipole resonances with mutual interference, thereby simultaneously achieving asymmetric transmission and linear polarization conversion. The proposed structure is designed, fabricated, and measured, which can realize a good agreement between the measurement results and the anticipation. Within the frequency range from 12.7 to 17 GHz, the AT parameter can be close to 0.9 and the polarization conversion ratio can be more than 93%.

The discovery of borospherene B₄₀ marks the onset of a new class of boron fullerenes and it is of current interest in chemical physics and, in particular, boron chemistry. In this work, density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations are carried out to study the structures, stabilities, photoelectron spectra, infrared spectra, Raman spectra and electronic absorption spectra of metalloborospherenes MB^0/− ₄₀ (M = Cu, Ag, and Au). It is found that Cu, Ag and Au atoms can form stable exohedral metalloborospherenes M&B^0/− ₄₀ (M = Cu, Ag, and Au) and endohedral metalloborospherenes M@B^0/− ₄₀ (M = Cu, Ag, and Au). In addition, the relative energies of these metalloborospherenes suggest that Cu, Ag and Au atoms favor the exohedral configuration. The Cu atom favors an exohedral geometry with the dopant face-capping a heptagon on the side surface (η7-Cu), whereas Ag and Au atoms favor exohedral geometries with the dopant bonding a side boron atom of the hexagonal ring. The calculated spectra suggest that doping of metal atoms in borospherene B₄₀ can change the spectral features since the extra metal atoms can modify the electronic structure of borospherene B₄₀. The addition of metal atoms can lead to more infrared and Raman active modes and redshift the electronic absorption spectra. The calculated results also show that metalloborospherenes MB^0/− ₄₀ (M = Cu, Ag, and Au) have different and meaningful spectral features, insight into the spectral properties is important to understand the compounds and reveal their potential applications. These spectral features can be readily compared with future spectroscopy measurements and used as fingerprints to identify and distinguish the metalloborospherenes MB^0/− ₄₀ (M = Cu, Ag, and Au).