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A metal-free porphyrin T4PP with a pyridine group is proposed as a new electrode for lithium/sodium-based dual-ion batteries (LDIBs/SDIBs). The electrochemical performance and reaction mechanism of T4PP are explored thoroughly. The extended porphyrin conjugated structure by the pyridine groups enables an excellent cycle life (5000 cycles) and a high-power density (18.7 kW kg−1). A hybrid charge-storage mechanism with the contribution of both cations and anions benefits fast charge transfer. [ABSTRACT FROM AUTHOR]

KTiOPO4 (KTP) is a classic commercial nonlinear optical (NLO) crystal, but its narrow bandgap (3.52 eV) prevents its practical application in the ultraviolet (UV) region. Many trials to widen the narrow bandgap of KTP have failed in the past few decades. A chemical cosubstitution strategy was implemented to design new members of the KTP-type family as potential UV NLO materials. First, a novel centrosymmetric KTP-type compound NH4SbFPO4·H2O with a sharply enlarged bandgap (5.01 eV) was obtained through three-site aliovalent substitution. Second, the noncentrosymmetric NH4SbF2SO4 was synthesized by the introduction of more F− anions to destroy the crystal symmetry and SO42− to replace PO43− for balancing the charge in NH4SbFPO4·H2O, which realized the transformation from a visible phosphate system to solar blind UV sulfate system for KTP-type family NLO materials. The preliminary experimental results indicated that NH4SbF2SO4 is a promising solar blind UV NLO material. The first-principles calculations revealed that the sharply enlarged bandgap resulted from the substitution of the transition metal cations with the main group metal cations and the introduction of F− anions with high electronegativity. [ABSTRACT FROM AUTHOR]

Although Cu–In–Se (CISe) quantum dots (QDs) with narrow tunable bandgap and low toxicity have promising prospects in photovoltaics, their application is seriously restricted by high defect density. To develop a facile synthesis method for high-quality CISe QDs, Al and Zn ions were introduced into the synthesis of CISe QDs. Compared with the incorporation of Al or Zn alone, the trap-state defects in CISe QDs can be more effectively reduced by the co-incorporation of these metal ions. The synthesized CISe QDs then were used as light harvester materials to fabricate photoanodes for constructing quantum dot sensitized solar cells (QDSCs). The photovoltaic performance of the QDSCs based on Al/Zn co-incorporated QDs was observed to be much better than that of the QDSCs based on Al or Zn alone incorporated QDs, which could be ascribed to the suppression of unfavorable charge combination in QDSCs. A power conversion efficiency (PCE) of 10.27% (Jsc = 27.15 mA cm−2, Voc = 0.620 V, and FF = 61.0%) was achieved on the QDSCs with Cu2S/brass counter electrodes and polysulfide electrolyte under simulated one full sun illumination, which is among the reported best PCEs of the QDSCs with a similar structure. [ABSTRACT FROM AUTHOR]

Four antimony fluoride sulfates named A2SO4·SbF3 (A = Na+, NH4+, K+, Rb+) have been successfully synthesized using a hydrothermal method by introducing Sb3+ cations with a stereochemically active lone pair in sulfates and subsequently tuning the structure through the second monovalent cations. All of the title compounds are stoichiometrically equivalent materials which share a common structural motif composed of a distorted SO4 tetrahedron and an asymmetric SbF3 polyhedron. However, the macroscopic centricities of these four compounds are significantly influenced by the size and coordination environment of cations; Na2SO4·SbF3 crystallizes in centrosymmetric space groups Cmca and (NH4)2SO4·SbF3 in Pbca, while K2SO4·SbF3 and Rb2SO4·SbF3 crystallizes in noncentrosymmetric space group P212121. Complete characterization including thermal analyses, infrared and UV-vis spectroscopy, and theoretical calculations is also reported. Powder second harmonic generation measurement for noncentrosymmetric K2SO4·SbF3 and Rb2SO4·SbF3 indicated that both of them are type I phase-matchable. [ABSTRACT FROM AUTHOR]