Ambient-Condition Recoverable Polymeric N Discovered from the Predicted Zr-N Compounds.

Polynitrogen has been widely studied recently as a rising star of high energy density materials. Here, we performed a systematic study of the Zr-N compounds in the N-rich region by the first-principles method. The high-pressure phase diagram of the Zr-N system is enriched by proposing five new compounds.

Realizing long range π-conjugation in phenanthrene and phenanthrene-based molecular crystals for anomalous piezoluminescence.

Unlike the known aggregation-caused quenching (ACQ) that the enhancement of π-π interactions in rigid organic molecules usually decreases the luminescent emission, here we show that an intermolecular "head-to-head" π-π interaction in the phenanthrene crystal, forming the so-called "transannular effect", could result in a higher degree of electron delocalization and thus photoluminescent emission enhancement. Such a transannular effect is molecular configuration and stacking dependent, which is absent in the isomers of phenanthrene but can be realized again in the designed phenanthrene-based cocrystals. The transannular effect becomes more significant upon compression and causes anomalous piezoluminescent enhancement in the crystals.

Anomalous pressure-responsive emission enhancement of FCO-CzS due to molecular configuration and electronic structure changes.

Studying the stimuli-responsive properties of luminescent materials is important for their applications, while the luminescent materials studied up to now usually exhibit emission quenching and red shift in photoluminescence (PL) energy upon compression. Designing luminescent material with abnormal pressure responses remains challenging. Here, we report the discovery of abnormal luminescent properties of FCO-CzS upon compression.

Novel polymeric phases proposed by cold-pressing SiC tubes.

A detailed structural evolution behavior of SiC single-wall nanotubes (SiC SWNTs) under high-pressure is studied by using density functional theory. We proposed four new polymeric phases (hP4-SiC, hP48-SiC, oI32-SiC and oA40-SiC), which possess the high stability, outstanding electronic and mechanical properties. The hP4-SiC, hP48-SiC and oA40-SiC are indirect band gap semiconductors, while the oI32-SiC is direct band gap semiconductor.

Pressure-stabilized polymerization of nitrogen in manganese nitrides at ambient and high pressures.

Two stable high-pressure phases (2/-MnN and 1̄-MnN) and four metastable phases (4/-MnN, 1̄-MnN, 2/-MnN and 1̄-MnN) are proposed by using evolutionary simulations. Besides the reported quasi-diatomic molecule N, the armchair chain and S-like chain, the N ring and N ring are firstly reported in the 4/-MnN and 1̄-MnN phases. A detailed study is performed on the energetic properties, mechanical properties and stability of these polynitrogen structures.

Interface-Induced Self-Assembly Strategy Toward 2D Ordered Mesoporous Carbon/MXene Heterostructures for High-Performance Supercapacitors.

Invited for this month's cover is the group of Zhen-An Qiao at the Jilin University. The image shows the application of 2D ordered mesoporous carbon/MXene heterostructures in supercapacitors. The Full Paper itself is available at 10.

Interface-Induced Self-Assembly Strategy Toward 2D Ordered Mesoporous Carbon/MXene Heterostructures for High-Performance Supercapacitors.

Two-dimensional transition metal carbonitrides (MXene) have demonstrated great potential in many fields. However, the serious aggregation and poor thermodynamic stability of MXene greatly hinder their applications. Here, an interface-induced self-assembly strategy to synthesize ordered mesoporous carbon/Ti C T heterostructures (OMCTs) was developed.

Pressure-Induced Electronic and Structural Transition in Nodal-Line Semimetal ZrSiSe.

The nodal-line semimetals have recently gained attention as a promising material due to their exotic electronic structure and properties. Here, we investigated the structural evolution and physical properties of nodal-line semimetal ZrSiSe under pressure via experiments and theoretical calculations. An isostructural electronic transition is observed at ∼6 GPa.

Pressure tuned photoluminescence and band gap in two-dimensional layered g-CN: the effect of interlayer interactions.

We show that the photoluminescence (PL) emission color of few layered g-CN (FL-CN) can be tuned from blue to yellow by applying pressure. FL-CN also exhibits an anomalous PL enhancement and obvious change in the light absorption at very low pressure. Further studies reveal that the increase of pressure-induced interlayer interactions affects the charge separation of photo-induced electrons and holes and thus leads to PL enhancement.

Decompression-Induced Diamond Formation from Graphite Sheared under Pressure.

Graphite is known to transform into diamond under dynamic compression or under combined high pressure and high temperature, either by a concerted mechanism or by a nucleation mechanism. However, these mechanisms fail to explain the recently reported discovery of diamond formation during ambient temperature compression combined with shear stress. Here we report a new transition pathway for graphite to diamond under compression combined with shear, based on results from both theoretical simulations and advanced experiments.