Molecular ferroelectric HDA-BiI5 has been utilized as the light-absorbing layer for organic-inorganic hybrid solar cells.

With the aim of promoting the photocatalytic activity for water splitting, a novel core-shell-structured crystalline-BaTiO3/amorphous-BaTiO3-x/crystalline-CdS composite nanocubes are prepared by a two-step facile synthesis approach. The basic characterization techniques such...

Molecular ferroelectrics with narrow bandgaps has great potential in the photoelectric field, but the outstanding species are still scarce. Herein, [C6N2H18]­[SbI5] has been demonstrated as a room-temperature (RT) molecular ferroelectric and applied to the organic–inorganic hybrid solar cells as the light-absorbing layer. The polar orthorhombic structure was solved by single-crystal XRD. The inherent RT ferroelectricity was revealed by hysteresis measurements with superior saturation polarization (P s), remanent polarization (P r), and coercive field (E c) as 12.55 μC/cm2, 10.78 μC/cm2, and 0.33 kV/cm, respectively. The [C6N2H18]­[SbI5]-based solar device exhibits a significant photovoltaic (PV) effect under AM 1.5 G illumination with V oc ∼ 0.43 V, J sc ∼ 35.17 μA/cm2, and a fast response time of ∼0.33 ms. A dramatical enhancement in PV performance has been achieved by turning the ferroelectric polarization, leading to the maximum V oc ∼ 0.75 V, J sc ∼ 1.09 mA/cm2, and a power conversion efficiency (PCE) of 0.29%. This work offers a bright avenue for molecular ferroelectrics in optoelectronic devices.

No abstract

A frequency-tunable cloak with semiconducting constituents has been proposed by modifying the dielectric constant by externally controlling the free-carrier density. We have theoretically studied that the cloaking frequency of a single-layer shell consisting of intrinsic InSb can be tuned by varying the temperature based on the Mie scattering theory. The calculated results show that this tunable cloak has a large bandwidth of over 0.3 THz, a tunability of cloaking frequency of 17 GHz K−1 with temperature and a dramatic reduction in the total scattering cross section of 90% at cloaking frequencies. It is also possible to realize a tunable cloak of extrinsic semiconductor Ge by changing the impurity density with current injection.

Ferroelectric photovoltaics as a new type solar cell, relied on an internal electric field instead of p-n or Schottky junctions, can considerably improve the efficiency of charge separation and migration....

We have theoretically suggested a temperature-dependent superconducting cloak whose cloaking frequency can be externally controlled, since the dielectric constant of the superconductor is well tuned with the operating temperature. The results show that this tunable cloak exhibits a fine tunability in the low-temperature range 0–0.3 T c and a fast tunability in the high-temperature range 0.3T c–T c, together with a large reduction in scattering (<−50 dB). It may provide a potential way to design a tunable cloak with considerable flexibility.

No abstract