Publications by authors named "Martin K Schreyer"

CeNbO4.25 is reported to exhibit fast oxygen ion diffusion at moderate temperatures, making this the prototype of a new class of ion conductor with applications in a range of energy generation and storage devices. To date, the mechanism by which this ion transport is achieved has remained obscure, in part due to the long-range commensurately modulated structural motif.

View Article and Find Full Text PDF

Multiphoton upconversion is a process where two or more photons are absorbed simultaneously to excite an electron to an excited state and, subsequently, the relaxation of electron gives rise to the emission of a photon with frequency greater than those of the absorbed photons. Materials possessing such property attracted attention due to applications in biological imaging, photodynamic therapy, three-dimensional optical data storage, frequency-upconverted lasing and optical power limiting. Here we report four-photon upconversion in metal-organic frameworks containing the ligand, trans, trans-9,10-bis(4-pyridylethenyl)anthracene.

View Article and Find Full Text PDF
Article Synopsis
  • Solid-state [2+2] photochemical cycloaddition reactions have been studied since the 1960s, particularly focusing on trans-1,2-bis(4'-pyridyl)ethylene (bpe), which yields mainly the rctt-tpcb isomer.
  • This study presents a method for synthesizing a different isomer, rtct-tpcb, through thermal isomerization of the rctt-isomer in air, suggesting a radical chain mechanism involving molecular oxygen.
  • The findings are backed by various techniques, including spectral studies and calculations, indicating that this thermal isomerization could be a broader method for producing desirable stereoisomers from existing cyclobutane derivatives.
View Article and Find Full Text PDF

Apatite-like materials are of considerable interest as potential solid oxide fuel cell electrolytes, although their structural vagaries continue to attract significant discussion. Understanding these features is crucial both to explain the oxide ion conduction process and to optimise it. As the composition of putative P6(3)/m apatites with ideal formula [A(I)(4)][A(II)(6)][(BO(4))(6)][X](2) is varied the [A(I)(4)(BO(4))(6)] framework will flex to better accommodate the [A(II)(6)X(2)] tunnel component through adjustment of the A(I)O(6) metaprism twist angle (varphi).

View Article and Find Full Text PDF