Incorporation of 2D pyreneammonium iodide for enhancing the efficiency and stability of perovskite solar cells

Despite the excellent performance of three-dimensional (3D) perovskite-based solar cells (PSCs), their poor stability under moisture and heating conditions limits their commercial application. To address this issue, a new pyreneammonium iodide (named TAPPyI), in which the pyrene-based compound 4,4',4'',4'''-(1,8-dihydropyrene-1,3,6,8-tetrayl)tetraaniline (named TAPPy) acts as the 2D cation, is introduced into 3D perovskite precursor solution for forming a 2D/3D heterostructured perovskite, which improves the quality of the perovskite film and enhances the stability of the perovskite film against moisture and heating. The planar pyrene endows TAPPyI with good charge transport properties, while the iodide on the arylamine side group effectively passivates the perovskite defects, thereby suppressing non-radiative recombination losses. Finally, the power conversion efficiency (PCE) of the TAPPyI-modified PSC is increased from 20.51% in the reference PSC to 22.73%. Furthermore, the stability of the TAPPyI-modified PSC is greatly improved, retaining 86% of the initial PCE after 360 hours in an environment of 85 °C and 85% humidity (ISOS-D-3), whereas the reference PSC only retains 2%. This work demonstrates that the conjugated planar molecule as a 2D cation to construct a 2D/3D heterostructured perovskite, which combines the good stability of 2D perovskite with the excellent carrier transport properties of 3D perovskite, can greatly enhance the efficiency and stability of PSCs.

High-Performance Anode Material Based on Zinc Naphthalocyanine/Graphene Composite

Transition metal oxides are a potential anode material owing to their high theoretical capacity. Nonetheless, their large volume changes and low electrical conductivities lead to poor cycling performance and rate capabilities. In this article, an effective strategy is proposed and developed for preparing a ZnO/N-doped graphene composite (ZnNc/GO-5). The key point of this strategy is to use zinc tetra tert-butyl-naphthalocyanine (ZnNc) as a codoped source of N atoms and zinc ions, and graphene oxide (GO) which is combined with ZnNc by π-π deposition as a carbon matrix. After calcination, ZnO microcrystals coated with N-doped graphene are obtained. The unique features of the composite and synergistic effect between N-doped reduced graphene oxide and ZnO microcrystals enable good electrochemical performance by the composites when used in lithium-ion batteries. As an anode material, the as-synthesized ZnNc/GO-5 composite delivers a high first capacity of 1942.9 mAh g-1 and excellent cyclic stability of 861.4 mAh g-1 after 150 cycles at 100 mA g-1. This strategy may offer a new method of designing the anode materials of lithium-ion batteries and promote the practical use of organic molecules in next-generation lithium-ion batteries.

Dual Emissive Zn(II) Naphthalocyanines: Synthesis, Structural and Photophysical Characterization with Theory-Supported Insights towards Soluble Coordination Compounds with Visible and Near-Infrared Emission

Metal phthalocyaninates and their higher homologues are recognized as deep-red luminophores emitting from their lowest excited singlet state. Herein, we report on the design, synthesis, and in-depth characterization of a new class of dual-emissive (visible and NIR) metal naphthalocyaninates. A 4-N,N-dimethylaminophen-4-yl-substituted naphthalocyaninato zinc(II) complex (Zn-NMe2Nc) and the derived water-soluble coordination compound (Zn-NMe3Nc) exhibit a near-infrared fluorescence from the lowest ligand-centered state, along with a unique push-pull-supported luminescence in the visible region of the electromagnetic spectrum. An unprecedentedly broad structural (2D-NMR spectroscopy and mass spectrometry) as well as photophysical characterization (steady-state state and time-resolved photoluminescence spectroscopy) is presented. The unique dual emission was assigned to two independent sets of singlet states related to the intrinsic Q-band of the macrocycle and to the push-pull substituents in the molecular periphery, respectively, as predicted by TD-DFT calculations. In general, the elusive chemical aspects of these macrocyclic compounds are addressed, involving both reaction conditions, thorough purification, and in-depth characterization. Besides the fundamental aspects that are investigated herein, the photoacoustic properties were exemplarily examined using phantom gels to assess their tomographic imaging capabilities. Finally, the robust luminescence in the visible range arising from the push-pull character of the peripheral moieties demonstrated a notable independence from aggregation and was exemplarily implemented for optical imaging (FLIM) through time-resolved multiphoton micro(spectro)scopy.

Photoactive layers for photovoltaics based on near-infrared absorbing aryl-substituted naphthalocyanine complexes: preparation and investigation of properties

Photoactive layers based on substituted naphthalocyanines and conductive polymer MEH-PPV were prepared using the spin-coating technique and their conductivity was tested in dark and under illumination.