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.

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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.