Intrinsic Low Temperature Paramagnetism in B-DNA

We present experimental study of magnetization in $\lambda$-DNA in conjunction with structural measurements. The results show the surprising interplay between the molecular structures and their magnetic property. In the B-DNA state, $\lambda$-DNA exhibits paramagnetic behaviour below 20 K that is non-linear in applied magnetic field whereas in the A-DNA state, remains diamagnetic down to 2 K. We propose orbital paramagnetism as the origin of the observed phenomena and discuss its relation to the existence of long range coherent transport in B-DNA at low temperature.Comment: 5 pages, 4 figures, submitted to Physical Review Letters October 200

Status report on emerging photovoltaics

\ua9 2023 Society of Photo-Optical Instrumentation Engineers (SPIE).This report provides a snapshot of emerging photovoltaic (PV) technologies. It consists of concise contributions from experts in a wide range of fields including silicon, thin film, III-V, perovskite, organic, and dye-sensitized PVs. Strategies for exceeding the detailed balance limit and for light managing are presented, followed by a section detailing key applications and commercialization pathways. A section on sustainability then discusses the need for minimization of the environmental footprint in PV manufacturing and recycling. The report concludes with a perspective based on broad survey questions presented to the contributing authors regarding the needs and future evolution of PV

Radiation chemistry of solid-state carbohydrates using EMR

We review our research of the past decade towards identification of radiation-induced radicals in solid state sugars and sugar phosphates. Detailed models of the radical structures are obtained by combining EPR and ENDOR experiments with DFT calculations of g and proton HF tensors, with agreement in their anisotropy serving as most important criterion. Symmetry-related and Schonland ambiguities, which may hamper such identification, are reviewed. Thermally induced transformations of initial radiation damage into more stable radicals can also be monitored in the EPR (and ENDOR) experiments and in principle provide information on stable radical formation mechanisms. Thermal annealing experi-ments reveal, however, that radical recombination and/or diamagnetic radiation damage is also quite important. Analysis strategies are illustrated with research on sucrose. Results on dipotassium glucose-1-phosphate and trehalose dihydrate, fructose and sorbose are also briefly discussed. Our study demonstrates that radiation damage is strongly regio-selective and that certain general principles govern the stable radical formation

Laboratory protocols for measuring and reporting the performance of luminescent solar concentrators

Luminescent solar concentrators (LSCs) show great potential for both broadening the spectral response of photovoltaic devices and facilitating their deployment in urban environments. However, the recent success of LSCs has brought to light severe deficiencies in reporting protocols: direct comparison between lab-scale LSCs is not possible due to inconsistencies in the experimental measurements and reporting of device performance. Here, we make the case for treatment of LSCs as photonic devices rather than photovoltaic cells and identify best practice guidelines for the measurement and reporting of LSC performance

The Interplay between Different Stimuli in a 4D Printed Photo-, Thermal-, and Water-Responsive Liquid Crystal Elastomer Actuator

Multi-stimuli responsivity in 3D-printed objects is receiving much attention. However, the simultaneous interplay between different environmental stimuli is largely unexplored. In this work, we demonstrate direct ink writing of an oligomeric ink containing an azobenzene photo-switch with an accessible hydrogen bond allowing triple responsivity to light, heat, and water. The resulting printed liquid crystal elastomer performs multiple actuations, the specific response depending on the environmental conditions. Bilayer films formed by printing on a static substrate can rapidly change shape, bending almost 80 degrees if irradiated in air or undergoing a shrinkage of about 50 % of its length when heated. The bilayer film assumes dramatically different shapes in water depending on combined environmental temperature and lighting conditions

Dye-doped polysiloxane rubbers for luminescent solar concentrator systems

We here report on our investigation of the properties of polysiloxane rubber waveguides doped with Lumogen Red 305 for the production of luminescent solar concentrator (LSC) devices. Samples with different dye concentrations were produced and their optical properties were characterized by absorption and fluorescence spectroscopy measurements. Moreover, different concentrations of Au nanoparticles were dispersed in the matrix in order to study the possibility of enhancing the fluorophore fluorescence yield. The light output from the edges of the samples, irradiated with a solar simulator was measured with an integrating sphere and the light yield was compared to that obtained with polycarbonate waveguides containing the same amount of the fluorescent dye BASF Lumogen Red305. Preliminary results from measurements with a GaAs photovoltaic cell and a silicon photodiode coupled to the polysiloxane waveguides are also presented