This meta-analysis suggests that surgical resection provides survival benefits in patients with intermediate- to advanced-stage HCC. The evidence found herein may assist in the choice of treatment modality based on diverse definitions of operability. (Hepatology 2018).
Chiral perovskites are being extensively studied as a promising candidate for spintronic- and polarization-based optoelectronic devices due to their interesting spin-polarization properties. However, the origin of chiroptical activity in chiral perovskites is still unknown, as the chirality transfer mechanism has been rarely explored. Here, through the nano-confined growth of chiral perovskites (MBA2PbI4(1-x)Br4x), we verified that the asymmetric hydrogen-bonding interaction between chiral molecular spacers and the inorganic framework plays a key role in promoting the chiroptical activity of chiral perovskites. Based on this understanding, we observed remarkable asymmetry behavior (absorption dissymmetry of 2.0 × 10−3 and anisotropy factor of photoluminescence of 6.4 × 10−2 for left- and right-handed circularly polarized light) in nanoconfined chiral perovskites even at room temperature. Our findings suggest that electronic interactions between building blocks should be considered when interpreting the chirality transfer phenomena and designing hybrid materials for future spintronic and polarization-based devices.
Chiral perovskites have emerged as promising candidates
for polarization-sensing
materials. Despite their excellent chiroptical properties, the nature
of their multiple-quantum-well structures is a critical hurdle for
polarization-based and spintronic applications. Furthermore, as the
origin of chiroptical activity in chiral perovskites is still illusive,
the strategy for simultaneously enhancing the chiroptical activity
and charge transport has not yet been reported. Here, we demonstrated
that incorporating a Lewis base into the lattice can effectively tune
the chiroptical response and electrical properties of chiral perovskites.
Through solid-state nuclear magnetic resonance spectroscopic measurements
and theoretical calculations, it was demonstrated that the material
property manipulation resulted from the change in the time-averaged
structure induced by the Lewis base. Finally, as a preliminary proof
of concept, a vertical-type circularly polarized light photodetector
based on chiral perovskites was developed, exhibiting an outstanding
performance with a distinguishability of 0.27 and a responsivity of
0.43 A W–1.
In principle, the induced chirality of hybrid perovskites results from symmetry-breaking within inorganic frameworks. However, the detailed mechanism behind the chirality transfer remains unknown due to the lack of systematic studies. Here, using the structural isomer with different functional group location, we deduce the effect of hydrogen-bonding interaction between two building blocks on the degree of chirality transfer in inorganic frameworks. The effect of asymmetric hydrogen-bonding interaction on chirality transfer was clearly demonstrated by thorough experimental analysis. Systematic studies of crystallography parameters confirm that the different asymmetric hydrogen-bonding interactions derived from different functional group location play a key role in chirality transfer phenomena and the resulting spin-related properties of chiral perovskites. The methodology to control the asymmetry of hydrogen-bonding interaction through the small structural difference of structure isomer cation can provide rational design paradigm for unprecedented spin-related properties of chiral perovskite.
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