ABSTRACT
Organic-inorganic lead halide perovskite solar cells (PSCs) attract great research interest due to their significant device performance and optoelectronic properties. However, reducing charge recombination and efficiency loss due to surface defects of the perovskite layer are still big issues to overcome for PSCs. Herein, we have employed a simple molecule, 2-thiophenecarboxylic acid (2TiCOOH), via post-treatment to passivate the uncoordinated Pb2+ on the perovskite film surface and improve the stability at the perovskite/Spiro-OMeTAD interface. The spectral results illustrate that the 2TiCOOH passivated devices exhibit higher carrier lifetime, charge extraction, and minimized defect induced recombination. Also, solar cells with 2TiCOOH show better charge collection, improved JSC, FF, and outstanding power conversion efficiency (PCE). In addition, 2TiCOOH passivated solar cells show tremendously stable performance output with less than 1% PCE drop after 100 days. This work provides a facile surface passivation strategy for fabricating highly efficient, low cost, and stable perovskite solar cells, which can be used for large scale technology and commercialization.
ABSTRACT
The design and preparation of transition-metal complexes with Schiff base ligands are of interest due to their potential applications in the fields of molecular magnetism, nonlinear optics, dye-sensitized solar cells (DSSCs), sensing and photoluminescence. Luminescent metal complexes have been suggested as potential phosphors in electroluminescent devices. A new luminescent nickel(II) complex, [Ni(C10H10Cl2NO2)2], has been synthesized and characterized by single-crystal X-ray diffraction and elemental analysis, UV-Vis, FT-IR, 1H NMR, 13C NMR and photoluminescence spectroscopies, and LC-MS/MS. Molecules of the complex in the crystals lie on special positions, on crystallographic binary rotation axes. The NiII atoms are six-coordinated by two phenolate O, two imine N and two hydroxy O atoms from two tridentate Schiff base 2,4-dichloro-6-[(2-hydroxypropyl)iminomethyl]phenolate ligands, forming an elongated octahedral geometry. Furthermore, the complex exhibits a strong green luminescence emission in the solid state at room temperature, as can be seen from the (CIE) chromaticity diagram, and hence the complex may be a promising green OLED (organic light-emitting diode) in the development of electroluminescent materials for flat-panel-display applications.
