Highly oriented quasi-2D layered tin halide perovskites with 2-thiopheneethylammonium iodide for efficient and stable tin perovskite solar cells

3D tin-based halide perovskites are promising light absorbers for the perovskite solar cells (PSCs) due to their non-toxicity, suitable optical band gaps, and excellent optoelectronic properties. However, the inherent rapid...

Photochemical α-Aminonitrile Synthesis using Zn Phthalocyanines as Near Infrared Photocatalysts

While photochemical transformations with sunlight almost exclusively utilize the UV-Vis part of the solar spectrum, the majority of the photons emitted by the sun have frequencies in the near-infrared region. Phthalocyanines show high structural similarity to the naturally occurring light harvesting porphyrins, chlorins and mainly bacteriochlorins, and are also known for being efficient and affordable near-infrared light absorbers as well as triplet sensitizers for the production of singlet oxygen. Although having been neglected for a long time in synthetic organic chemistry due to their low solubility and high tendency towards aggregation, their unique photophysical properties and chemical robustness make phthalocyanines attractive photocatalysts for the application in near-infrared light-driven synthesis strategies. Herein, we report a cheap, simple and efficient photocatalytic protocol, which is easily scalable under continuous flow conditions. Various phthalocyanines were studied as near-infrared photosensitizers in oxidative cyanations of tertiary amines to generate α-aminonitriles, a synthetically versatile compound class.

Chalcogenide Perovskites and Perovskite-Based Chalcohalide as Photoabsorbers: A Study of Their Properties, and Potential Photovoltaic Applications

In 2015, a class of unconventional semiconductors, Chalcogenide perovskites, remained projected as possible solar cell materials. The MAPbI3 hybrid lead iodide perovskite has been considered the best so far, and due to its toxicity, the search for potential alternatives was important. As a result, chalcogenide perovskites and perovskite-based chalcohalide have recently been considered options and potential thin-film light absorbers for photovoltaic applications. For the synthesis of novel hybrid perovskites, dimensionality tailoring and compositional substitution methods have been used widely. The study focuses on the optoelectronic properties of chalcogenide perovskites and perovskite-based chalcohalide as possibilities for future photovoltaic applications.

Electronic, Optical, and Thermoelectric Properties of Bulk and Monolayer Germanium Tellurides

Electronic, optical, and thermoelectric properties of germanium tellurides (GeTe) were investigated through a series of first-principles calculations of band structures, absorption coefficients, and thermoelectric transport coefficients. We consider bulk GeTe to consist of cubic and rhombohedral phases, while the two-dimensional (2D) GeTe monolayers can form as a 2D puckered or buckled honeycomb crystals. All of the GeTe variants in the bulk and monolayer shapes are excellent light absorbers in a wide frequency range: (1) bulk cubic GeTe in the near-infrared regime, (2) bulk rhombohedral GeTe and puckered monolayer GeTe in the visible-light regime, and (3) buckled monolayer GeTe in the ultraviolet regime. We also found specifically that the buckled monolayer GeTe exhibits remarkable thermoelectric performance compared to the other GeTe phases due to a combination of electronic band convergence, a moderately wide band gap, and unique 2D density of states from the quantum confinement effect.

Activating [FeFe] hydrogenase mimic for hydrogen evolution under visible light

Inspired by the active center of the natural [FeFe] hydrogenases, we designed a compact and precious metal-free photosensitizer-catalyst dyad (PS-CAT) for photocatalytic hydrogen evolution under visible light irradiation. PS-CAT represents a prototype dyad comprising pi-conjugated oligothiophenes as light absorbers. PS-CAT and its interaction with the sacrificial donor 1,3-dimethyl-2-phenylbenzimidazoline were studied by steady-state and time-resolved spectroscopy coupled with electrochemical techniques and visible light-driven photocatalytic investigations. Operando EPR spectroscopy revealed the formation of an active [Fe(I)Fe(0)] species – in accordance with theoretical calculations – presumably driving photocatalysis effectively (TON ≈ 210).

[FeFe] Hydrogenase based Prototype Photosensitizer-Catalyst Dyad for Hydrogen Generation under Visible Light

Inspired by the active center of the natural [FeFe] hydrogenases, we designed a compact and precious metal-free photosensitizer-catalyst dyad (PS-CAT) for photocatalytic hydrogen evolution under visible light irradiation. PS-CAT represents a prototype dyad comprising pi-conjugated oligothiophenes as light absorbers. PS-CAT and its interaction with the sacrificial donor 1,3-dimethyl-2-phenylbenzimidazoline were studied by steady-state and time-resolved spectroscopy coupled with electrochemical techniques and visible light-driven photocatalytic investigations. Operando EPR spectroscopy revealed the formation of an active [Fe(I)Fe(0)] species – in accordance with theoretical calculations – presumably driving photocatalysis effectively (TON ≈ 210).

[FeFe] Hydrogenase based Prototype Photosensitizer-Catalyst Dyad for Hydrogen Generation under Visible Light

Inspired by the active center of the natural [FeFe] hydrogenases, we designed a compact and precious metal-free photosensitizer-catalyst dyad (PS-CAT) for photocatalytic hydrogen evolution under visible light irradiation. PS-CAT represents a prototype dyad comprising pi-conjugated oligothiophenes as light absorbers. PS-CAT and its interaction with the sacrificial donor 1,3-dimethyl-2-phenylbenzimidazoline were studied by steady-state and time-resolved spectroscopy coupled with electrochemical techniques and visible light-driven photocatalytic investigations. Operando EPR spectroscopy revealed the formation of an active [Fe(I)Fe(0)] species – in accordance with theoretical calculations – presumably driving photocatalysis effectively (TON ≈ 210).