The notoriously poor stability of perovskite solar cells is a crucial issue restricting commercial applications. Here, a fluorinated perylenediimide (F‐PDI) is first introduced into perovskite film to enhance the device's photovoltaic performance, as well as thermal and moisture stability simultaneously. The conductive F‐PDI molecules filling at grain boundaries (GBs) and surface of perovskite film can passivate defects and promote charge transport through GBs due to the chelation between carbonyl of F‐PDI and noncoordinating lead. Furthermore, an effective multiple hydrophobic structure is formed to protect perovskite film from moisture erosion. As a result, the F‐PDI‐incorporated devices based on MAPbI3 and Cs0.05 (FA0.83MA0.17)0.95 Pb (Br0.17I0.83)3 absorber achieve champion efficiencies of 18.28% and 19.26%, respectively. Over 80% of the initial efficiency is maintained after exposure in air for 30 days with a relative humidity (RH) of 50%. In addition, the strong hydrogen bonding of F···H‐N can immobilize methylamine ion (MA+) and thus enhances the thermal stability of device, remaining nearly 70% of the initial value after thermal treatment (100 °C) for 24 h at 50% RH condition.

Polynitrogen compounds especially pentazolate anion complexes recently have attracted substantial attention due to their promising potential as high-energy-density materials. Here, using a machine-learning-accelerated crystal structure search method and first-principles calculations, we predict a new hybrid compound by inserting a large fraction of nitrogen into alkaline-earth metals. It is a new stoichiometric type MN10 (M = Be, Mg), which possesses a metal-centering octahedral pentazolate framework with the space group Fdd2. This type of ionic-like molecular crystal is found to be energetically more favorable than the mixtures of M3N2 or MN4 compounds and pure nitrogen and is possibly synthesized at relatively low pressures (around 12 GPa for MgN10). The ab initio molecular dynamics simulations show that they are metastable and can be quenched to ambient conditions once synthesized at high pressure. Moreover, decomposition of this polymeric MN10 structure can release a large amount of energy and shows high performance in detonation. The detonation velocity and pressure of BeN10 are about twice and 4 times that of trinitrotoluene, respectively.

Superionic states are phases of matter that can simultaneously exhibit some of the properties of a liquid and of a solid. For example, in superionic ice, hydrogen atoms can move freely while oxygen atoms are fixed in their sublattice. "Superionicity" has attracted much attention both in fundamental science and applications. Helium is the most inert element in nature and it is generally considered to be unreactive. Here we use ab initio calculations to show that He and H2O can form stable compounds within a large pressure range which can exist even close to ambient pressure. Surprisingly, we find that they can form two previously unknown types of superionic states. In the first of these phases the helium atoms exhibit liquid behavior within a fixed ice-lattice framework. In the second of these phases, both helium and hydrogen atoms move in a liquid-like fashion within a fixed oxygen sublattice. Because the He-O interaction is weaker than the H-O interaction, the helium atoms in these superionic states have larger diffusion coefficients and lower "melting" temperatures than that of hydrogen, although helium is heavier than hydrogen. The insertion of helium atoms substantially decreases the pressure at which superionic states may be formed, compared to those in pure ice.