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Neutron Spectroscopy: An Under‐Utilised Tool for Organic Electronics Research?

“…In 2009 Obrzut and Page were the first to examine af unctional photovoltaic material using QENS when they looked at relaxation processes in conducting regioregular P3HT. [14] Ther esearchers took advantage of the high incoherent scattering cross-section of hydrogen atoms to selectively monitor the contribution of the side chains to molecular dynamics in the polymer.F igure 4a shows a" fixed elastic window scan", which plots the intensity of elastically scattered neutrons against temperature.Changes in gradient can indicate motions becoming active or inactive.B yc omparing the mean square displacement (Figure 4b)o ft he protons as af unction of temperature it was shown that the hexyl side chains are liberated at approximately 175 K, consistent with findings that long-range order in electronic states would approach that of amorphous silicon below 180 K. This relaxation of side groups was shown to contribute to topological disorder,hindering charge transport, and decreasing conductivity by 5o rders of magnitude at 190 K.…”

“…a) Normalized elastic-scattering intensity as af unction of temperature (at fixed Q % 0.99 À1 ). The solid line represents afit of the data using an instrumentresolution of 0.86 meV as determined from the dynamic scan at 50 K. b) Mean square displacement, < r 2 > , for P3HT as measured by QENS showing the onset of motions above 175 K. Reproduced with permission from ref [14]…”

1H and 23Na MAS NMR spectroscopy of cationic species in CO2 selective alkaline earth metal porous silicoaluminophosphates prepared via liquid and solid state ion exchange

“…Techniques such as conventional and multi step liquid state ion exchange [5,7], wetness impregnation [8] as well as solid state ion exchange [4,[9][10][11] have been studied to attain full exchange of the original charge-balancing species. However, full knowledge of the location and distribution of the charge-compensating cations inside zeolitic structures is of utmost importance to optimize ion exchange procedures and promote the occupancy of sites available for interaction with other extra-framework guest molecules or adsorbates (i.e., CO 2 ).…”

Catalytic conversion of methanol to olefins over rare earth (La, Y) modified SAPO-34

“…For this reason, increasing the ability of the catalyst to resist coke formation is a key challenge whose solution is urgently required for the practical MTO application [2,4,5]. Metal doping as a convenient way to control or alter the catalytic behavior was extensively investigated for the MTO reaction [4][5][6][7][8][9][10] with the goal of modifying the acidity of the zeolite [4,5,8] and adjusting the strength of T-O bond in the TO 4 tetrahedral unit of the zeolite framework. For instance, Zhu [6] and Djieugoue et al [7] reported that Cr incorporation into the framework of SAPO-n increased the lifetime of the zeolite.…”

“…However, the previously published articles mainly paid attention to transition metals and alkaline earth metals, rarely talked about the effect of rare earth metal doping on the lifetime of the catalyst in detail. Recently, Obrzut et al [10] found that the impregnation of SAPO-34 with K and Ce could remarkably reduce methane formation at 500°C. As is well-known, the formation of large amounts of methane was usually accompanied by a rapid deactivation of the catalyst [11], due to extra hydrogen drawing out from the residual hydrocarbon species.…”