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About 13 TW of energy is needed to sustain the lifestyle of people worldwide but an additional 10 TW clean energy will be required by 2050. The increase in the world population and the demand for energy that rely on fossil fuels has resulted in global warming that necessitates the need for alternative energy such as solar. Solar energy is abundant and readily available, and its use will contribute to sustainable development. Metal halide perovskites are promising materials for the development of next-generation solar cells. The power conversion efficiency (PCE) of 25.8% obtained for organolead halide perovskite is close to the polycrystalline solar cell’s efficiency at 26.3% and these materials offer great prospects for future photovoltaic development. To approach the theoretical efficiency limit, it is very important to study the development of perovskite solar cells in terms of material composition, fabrication techniques, and device architectures with emphasis on charge transport layers and electrodes. Limitations to PCE and stability of perovskites, optoelectronic properties, lifetime and stability, wide-scale applications, components of the perovskites solar cell, the standard for testing conditions for good stability and its evolution into the lower layered perovskite solar cells were examined in the current review.

C12H9N2Br, triclinic, P1‾$\overline{1}$ (no. 2), a = 7.4005(13) Å, b = 9.4122(16) Å, c = 9.7916(17) Å, α = 98.235(9)°, β = 101.744(8)°, γ = 111.005(7)°, V = 605.69(18) Å3, Z = 2, Rgt(F) = 0.0209, wRref(F2) = 0.0514, T = 100(2) K.

C12H9N2Br, triclinic, P 1 ‾ (no. 2), a = 7.4005(13) Å, b = 9.4122(16) Å, c = 9.7916(17) Å, α = 98.235(9)°, β = 101.744(8)°, γ = 111.005(7)°, V = 605.69(18) Å3, Z = 2, Rgt(F) = 0.0209, wRref(F2) = 0.0514, T = 100(2) K. [ABSTRACT FROM AUTHOR]

This study reports the synthesis and comparative investigation of the substituent effects of a new series of highly luminescent homoleptic tris-cyclometalated iridium(III) complexes of the type [Ir(N^C)3]. These are based on two ligand type derivatives comprising of 4-fluorophenylvinylquinolines and 4-methoxyphenylvinylquinolines with electron-donating and/or electron-withdrawing groups as aryl substituents at 2-position. The structures of the ligands and their complexes were characterized by means of FT-IR, UV-Vis and NMR spectrometry complemented with photoluminescence and cyclic voltammetry. The photophysical properties of 2-aryl-4-(4-fluorophenylvinyl)quinoline and its corresponding complex were also studied using the density functional theory method. The photoluminescent properties of the ligands and the corresponding complexes showed high fluorescent intensities and quantum yields in solvents of different polarities. The photoluminescence spectra of the complexes in solid film, showed common transmission curves at longer wavelengths maximum (λem = 697 nm) possibly originating from the interference of scattered light of higher-order transmission of monochromators. [ABSTRACT FROM AUTHOR]

A number of novel ruthenium(II) polypyridine complexes have been designed and synthesized for use as photosensitizers in dye-sensitized solar cells (DSSCs) due to their rich photophysical properties such as intense absorption, long-lived lifetimes, high emission quantum yields and unique redox characteristics. Many of these complexes exhibit photophysical behavior that can be readily controlled through a careful choice of ligands and/or substituents. With this perspective, we review the design and general synthetic methods of some polypyridine ligands based on bipyridine, phenanthroline, terpyridine and quaterpyridine with/without anchoring groups with a view to correlate functionality of ligand structures with the observed photophysical, electroredox and power conversion efficiency of some examples of Ru(II) polypyridyl complexes that have been reported and particularly used in the DSSCs applications. The main interest, however, is focused on showing the development of new polypyridine ligand materials containing long-range electron transfer motifs such as the alkenyl, alkynyl and polyaromatic donor functionalities. [ABSTRACT FROM AUTHOR]

South Africa is a country with a wide variety of plants that may contain excellent anti-tyrosinase inhibitors. With wide applications in cosmetics, pharmaceuticals and food products, tyrosinase inhibitors have received very special attention in the recent past as a way of preventing the overproduction of melanin in epidermal layers which often over time brings detrimental effects on human skin. In this present study, a fast screening method using a cyclic voltammetry technique was applied in the evaluation of methanolic extracts of twenty-five species of plants from the Lamiaceae family for anti-tyrosinase activity. Among these plants, those that showed a fast current inhibition rate at a minimum concentration when compared to a kojic acid standard were classified as having the greatest anti-tyrosinase activity. These include Salvia chamelaeagnea, S. dolomitica, Plectranthus ecklonii, P. namaensis, and P. zuluensis. The results presented herein focused in particular on providng firsthand information for further extensive research and exploration of natural product materials with anti-tyrosinase activity from South African flora for use in cosmetics, skin care and medicinal treatments. [ABSTRACT FROM AUTHOR]

With the aim of developing new molecular devices having long-range electron transfer in artificial systems and as photosensitizers, a series of homoleptic ruthenium(II) bisterpyridine complexes bearing one to three anthracenyl units sandwiched between terpyridine and 2-methyl-2-butenoic acid group are synthesized and characterized. The complexes formulated as bis-4'-(9-monoanthracenyl-10-(2-methyl-2-butenoic acid) terpyridyl) ruthenium(II) bis(hexafluorophosphate) (RBT1), bis-4'-(9-dianthracenyl-10-(2-methyl-2-butenoic acid) terpyridyl) ruthenium(II) bis(hexafluorophosphate) (RBT2), and bis-4'-(9-trianthracenyl-10-(2-methyl-2-butenoic acid) terpyridyl) ruthenium(II) bis(hexafluorophosphate) (RBT3) were characterized by elemental analysis, FT-IR, UV-Vis, photoluminescence, (1)H and (13)C NMR spectroscopy, and electrochemical techniques by elemental analysis, FT-IR, UV-Vis, photoluminescence, (1)H and (13)C NMR spectroscopy, and electrochemical techniques. The cyclic voltammograms (CVs) of (RBT1), (RBT2), and (RBT3) display reversible one-electron oxidation processes at E 1/2 = 1.13 V, 0.71 V, and 0.99 V, respectively (versus Ag/AgCl). Based on a general linear correlation between increase in the length of π-conjugation bond and the molar extinction coefficients, the Ru(II) bisterpyridyl complexes show characteristic broad and intense metal-to-ligand charge transfer (MLCT) band absorption transitions between 480-600 nm, ε = 9.45 × 10(3) M(-1) cm(-1), and appreciable photoluminescence spanning the visible region.