Cool carriers: triplet diffusion dominates upconversion yield.

Perovskites have gained popularity both as the active material in photovoltaics and as bulk triplet sensitizers for solid-state triplet-triplet annihilation upconversion (TTA-UC). Prior to widespread implementation into commercial photovoltaics, an in-depth understanding of the environmental influences on device performance is required. To this point, the temperature-dependent structure-function properties of TTA-UC within methylammonium formamidinium lead triiodide (MAFA)/rubrene UC devices are explored.

Effective Mass for Holes in Paramagnetic, Plasmonic CuFeS Semiconductor Nanocrystals.

The impact of a magneto-structural phase transition on the carrier effective mass in CuFeS plasmonic semiconductor nanocrystals was examined using Magnetic Circular Dichroism (MCD). Through MCD, the sample was confirmed as p-type from variable temperature studies from 1.8 - 75 K.

A Single Source, Scalable Route for Direct Isolation of Earth-Abundant Nanometal Carbide Water-Splitting Electrocatalysts.

Single-phase MCs (M = Fe, Co, and Ni) were prepared by solvothermal conversion of Prussian blue single source precursors. The single source precursor is prepared in water, and the conversion process is carried out in alkylamines at reaction temperatures above 200 °C. The reaction is scalable using a commercial source of Fe-PB.

Controlled Synthesis and Exploration of CuFeS Bornite Nanocrystals.

Plasmonic semiconductor nanocrystals (NCs) are a new and exciting class of materials that enable higher control of their localized surface plasmon resonance (LSPR) than metallic counterparts. Additionally, earth-abundant and non-toxic materials such as copper iron sulfides are gaining interest as alternatives to heavy metal-based semiconductor materials. Colloidal bornite (CuFeS) is an interesting but underexplored example of a heavy metal-free plasmonic semiconductor.

Influence of Metal Identity on Light-Induced Switchable Adsorption in Azobenzene-Based Metal-Organic Frameworks.

Energy-efficient capture and release of small gas molecules, particularly carbon dioxide (CO) and methane (CH), are of significant interest in academia and industry. Porous materials such as metal-organic frameworks (MOFs) have been extensively studied, as their ultrahigh porosities and tunability enable significant amounts of gas to be adsorbed while also allowing specific applications to be targeted. However, because of the microporous nature of MOFs, the gas adsorption performance is dominated by high uptake capacity at low pressures, limiting their application.

Thermal decarboxylation for the generation of hierarchical porosity in isostructural metal-organic frameworks containing open metal sites.

The effect of metal-cluster redox identity on the thermal decarboxylation of a series of isostructural metal-organic frameworks (MOFs) with tetracarboxylate-based ligands and trinuclear μ-oxo clusters was investigated. The PCN-250 series of MOFs can consist of various metal combinations (Fe, Fe/Ni, Fe/Mn, Fe/Co, Fe/Zn, Al, In, and Sc). The Fe-based system can undergo a thermally induced reductive decarboxylation, producing a mixed valence cluster with decarboxylated ligand fragments subsequently eliminated to form uniform mesopores.

The thermally induced decarboxylation mechanism of a mixed-oxidation state carboxylate-based iron metal-organic framework.

Investigations into a thermally generated decarboxylation mechanism for metal site activation and the generation of mesopores in a carboxylate iron-based MOF, PCN-250, have been conducted. PCN-250 exhibits an interesting oxidation state change during thermal treatment under inert atmospheres or vacuum conditions, transitioning from an Fe(iii) cluster to a Fe(ii)Fe(iii) cluster. To probe this redox event and discern a mechanism of activation, a combination of thermogravimetric analysis, gas sorption, scanning electron microscopy, Fe Mössbauer spectroscopy, gas chromatography-mass spectrometry, and X-ray diffraction studies were conducted.