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By introducing rare-earth metal-centered polyhedra to enhance the birefringence of non-π-conjugated sulfate systems, NaLa2(SO4)2F3 with a moderate birefringence (0.041 at 1064 nm) was successfully synthesized.

Herein, by introducing [AlO4] tetrahedra, a new aluminoborate was discovered. This work confirms that the introduction of [AlO4] tetrahedra can lead to the rearrangement of anionic framework of borate system and thereby enhance the birefringence.

In this study, ferrocenedicarboxylic acid (FDA) has been introduced between an ITO electrode and ZnO interlayer to improve the performance of inverted polymer solar cells. The highest power conversion efficiency (PCE) of 9.06% is achieved among the measurements. Besides, the average PCE of FDA/ZnO based devices is observed with 11.9% enhancement (8.73% vs. 7.80%) compared to ZnO-only devices. Electrical characterization, surface morphology, wetting properties, as well as exciton generation rate and dissociation probability were investigated to understand the impact of FDA insertion on the interfacial properties. It was found that exciton dissociation efficiency and charge collection efficiency were significantly improved after inserting FDA, while the surface morphology, average roughness and water contact angle of the ZnO film were not changed. It was thought that FDA connected to the ITO electrode and ZnO film because of its carboxyl groups, which lead to a compact interfacial contact and reduced charge recombination. In addition, the devices based on the FDA/ZnO interlayers displayed improved stability in the argon-filled glove box without any encapsulation for about 1000 h compared to the ZnO-only devices. This study provides a new idea to introduce materials with functional groups between ITO/metal oxides interfaces to achieve more efficient charge collection and device performance.

Two new tartratoborate nonlinear optical materials, KSr[C4H2O6B(OH)2]·4H2O (KSCB) and RbSr[C4H2O6B(OH)2]·4H2O (RSCB), have been prepared through slow evaporation at room temperature. Single-crystal X-ray diffraction data reveal that KSCB crystallizes in the triclinic system, space group P1 (no. 1). It consists of KO8 polyhedra, SrO9 polyhedra, BO4 tetrahedra, tartrate molecules and H2O molecules. The isolated tartratoborate anions are connected to form a three-dimensional network structure by sharing oxygen atoms with K+ and Sr2+. The structural data show that KSCB and RSCB are isostructural and noncentrosymmetric. KSCB and RSCB produce second-harmonic generation intensities of 1.5 × KH2PO4 and 1.7 × KH2PO4, respectively, and they are both type I phase-matchable. The UV-Vis diffuse reflectance spectra of these compounds indicate that they are both transparent from 250 to 850 nm. Related infrared spectra and thermal analyses were also performed.

A new non-centrosymmetric polyborate, Li5Rb2B7O14, has been synthesized. The structure of the title compound was solved by single-crystal X-ray diffraction analysis. The infinite three-dimensional structure of Li5Rb2B7O14 is constructed from bridged LiOn (n = 4, 5, 6) and RbO10 polyhedra with two kinds of one-dimensional B–O chain fundamental building blocks through their vertex oxygen atoms. It melts congruently and exhibits a short-wavelength absorption onset at 190 nm. The feature of a short UV cut off edge is favourable in practical applications. The calculated band structure and the density of states of Li5Rb2B7O14 suggest that its indirect energy gap is 4.247 eV. The materials have also been characterized by infrared spectroscopy and thermal analysis.

Single crystals of Li3Cs2B5O10 have been synthesized and its structure determined by single-crystal X-ray diffraction. Li3Cs2B5O10 crystallizes in the non-centrosymmetric space group C222(1) ( No. 20). The structure consists of isolated B5O10 groups that are bridged by LiOn (n = 4, 5) and CsOn (n = 8, 10) polyhedra through their vertex oxygen atoms to form an infinite three-dimensional structure. Li3Cs2B5O10 melts congruently and exhibits a short-wavelength absorption onset at 175 nm. As-prepared Li3Cs2B5O10 is both non-centrosymmetric and phase matchable as supported by second harmonic generation measurements.