Reply to Comment on "Critical analysis of a variational method used to describe molecular electron transport"

We show that the failure of the Delaney-Greer (DG) variational ansatz for transport demonstrated by us in Phys.\ Rev.\ B {\bf 80}, 165301 (2009) (I) is not related to an unsuitable constraint that prevents a broken time-reversal symmetry or to real orbitals, as DG incorrectly claim. The complex orbitals suggested by them as a way-out solution merely represent a particular case of the general case considered by us in I, which do not in the least affect our conclusion.Comment: Manuscript as submitted to Phys. Rev. B on 30 November 2010. Sections VII, VIII, and IX present significant details, which enlarge the analysis of the published versio

Sinusoidal nanotextures for light management in silicon thin film solar cells

Recent progresses in liquid phase crystallization enabled the fabrication of thin wafer quality crystalline silicon layers on low cost glass substrates enabling conversion efficiencies up to 12.1 . Because of its indirect band gap, a thin silicon absorber layer demands for efficient measures for light management. However, the combination of high quality crystalline silicon and light trapping structures is still a critical issue. Here, we implement hexagonal 750 nm pitched sinusoidal and pillar shaped nanostructures at the sun facing glass silicon interface into 10 m thin liquid phase crystallized silicon thin film solar cell devices on glass. Both structures are experimentally studied regarding their optical and optoelectronic properties. Reflection losses are reduced over the entire wavelength range outperforming state of the art anti reflective planar layer systems. In case of the smooth sinusoidal nanostructures these optical achievements are accompanied by an excellent electronic material quality of the silicon absorber layer enabling open circuit voltages above 600 mV and solar cell device performances comparable to the planar reference device. For wavelengths smaller than 400 nm and higher than 700 nm optical achievements are translated into an enhanced quantum efficiency of the solar cell devices. Therefore, sinusoidal nanotextures are a well balanced compromise of optical enhancement and maintained high electronic silicon material quality which opens a promising route for future optimizations in solar cell designs for silicon thin film solar cells on glas

Improved Light Management in Crystalline Silicon Thin Film Solar Cells by Advanced Nano Texture Fabrication

We present a texturing method for liquid phase crystallized silicon thin film solar cells enabling a maximum achievable short circuit current density of 36.5mA cm 2 due to optimized light management compared to current textured device

Tailoring nano textures for optimized light in coupling in liquid phase crystallized silicon thin film solar cells

Thin film solar cells based on liquid phase crystallized silicon LPC Si with 8 20 m thick absorber layers demand for advanced light management to achieve high photocurrent densities. Open circuit voltages Voc gt;600 mV underline the high silicon material quality of LPC silicon thin films on nano textured glass superstrates. We present a 500 nm pitched sinusoidal nano texture which outperforms larger pitched gratings with respect to light in coupling at the buried glass silicon interface. In the wavelength range of interest reflection of incident light is minimized to values close to 4 , which is the reflection at the sun facing air glass interface. Further, the electronic material quality of sinusoidally textured devices is analyzed on basis of a comparison of maximum achieved open circuit voltages on different texture types. The Voc on sinusoidally textured glass superstrates could be raised to 630 mV by changing the interlayer deposition method from a PVD to a PECVD process. Thus, we are able to unify high optical and electronic properties of silicon absorber layers on sinusoidal textured glass substrates. These results constitute a crucial step towards fully exploiting the optical potential of LPC silicon thin film solar cell

Antireflective nanotextures for monolithic perovskite silicon tandem solar cells

Recently, we studied the effect of hexagonal sinusoidal textures on the reflective properties of perovskite silicon tandem solar cells using the finite element method FEM . We saw that such nanotextures, applied to the perovskite top cell, can strongly increase the current density utilization from 91 for the optimized planar reference to 98 for the best nanotextured device period 500 nm and peak to valley height 500 nm , where 100 refers to the Tiedje Yablonovitch limit. [D. Chen et al., J. Photonics Energy 8, 022601, 2018 , doi 10.1117 1.JPE.8.022601] In this manuscript we elaborate on some numerical details of that work we validate an assumption based on the Tiedje Yablonovitch limit, we present a convergence study for simulations with the finite element method, and we compare different configurations for sinusoidal nanotexture

Effect of quantum nuclear motion on hydrogen bonding

This work considers how the properties of hydrogen bonded complexes, D-H....A, are modified by the quantum motion of the shared proton. Using a simple two-diabatic state model Hamiltonian, the analysis of the symmetric case, where the donor (D) and acceptor (A) have the same proton affinity, is carried out. For quantitative comparisons, a parametrization specific to the O-H....O complexes is used. The vibrational energy levels of the one-dimensional ground state adiabatic potential of the model are used to make quantitative comparisons with a vast body of condensed phase data, spanning a donor-acceptor separation (R) range of about 2.4-3.0 A, i.e., from strong to weak bonds. The position of the proton and its longitudinal vibrational frequency, along with the isotope effects in both are discussed. An analysis of the secondary geometric isotope effects, using a simple extension of the two-state model, yields an improved agreement of the predicted variation with R of frequency isotope effects. The role of the bending modes in also considered: their quantum effects compete with those of the stretching mode for certain ranges of H-bond strengths. In spite of the economy in the parametrization of the model used, it offers key insights into the defining features of H-bonds, and semi-quantitatively captures several experimental trends.Comment: 12 pages, 8 figures. Notation clarified. Revised figure including the effect of bending vibrations on secondary geometric isotope effect. Final version, accepted for publication in Journal of Chemical Physic

Imprinted Nanostructures for Light Management in Crystalline Silicon Thin Film Solar Cells on Glass

We present various imprinted nanostructures for light management in liquid phase crystallized silicon thin film solar cells enabling both, increased jsc by enhanced absorption and excellent electronic material quality with Voc values above 640 m

Optical simulations of advanced light management for liquid phase crystallized silicon thin film solar cells

Light management is a key issue for highly efficient liquid phase crystallized silicon LPC Si thin film solar cells and can be achieved with periodic nanotextures. They are fabricated with nanoimprint lithography and situated between the glass superstrate and the silicon absorber. To combine excellent optical performance and LPC Si material quality leading to open circuit voltages exceeding 640 mV, the nanotextures must be smooth. Optical simulations of these solar cells can be performed with the finite element method FEM . Accurately simulating the optics of such layer stacks requires not only to consider the nanotextured glass silicon interface, but also to adequately account for the air glass interface on top of this stack. When using rigorous Maxwell solvers like the finite element method FEM , the air glass interface has to be taken into account a posteriori, because the solar cells are prepared on thick glass superstrates, in which light is to be treated incoherently. In this contribution we discuss two different incoherent a posteriori corrections, which we test for nanotextures between glass and silicon. A comparison with experimental data reveals that a first order correction can predict the measured reflectivity of the samples much better than an often applied zeroth order correctio

Facing the challenge of liquid phase crystallizing silicon on textured glass substrates

A major limitation in current liquid phase crystallized LPC silicon thin film record solar cells are optical losses caused by their planar glass silicon interface. In this study, silicon is grown on nanoimprinted periodically as well as on randomly textured glass substrates and successfully implemented into state of the art LPC silicon thin film solar cell stacks. By systematically varying every layer the whole sample stack is optimized regarding its anti reflection ability. Compared to an optimized planar reference device, a reduction of reflection losses by 3.5 absolute on the random and by 9.4 absolute on the periodic texture has been achieved in the wavelength range of interes

Structured physical activity interventions as a complementary therapy for patients with inflammatory bowel disease – a scoping review and practical implications

Background: Patients with Inflammatory Bowel Disease (IBD) also suffer from a wide range of additional disorders, which may be caused by the disease, the side effect of the medication, or a lack of physical activity (PA). This results in reduced physical and psychological wellbeing. However, as known from other chronic diseases exercise could be utilized as supportive therapy for IBD patients. Main goals of this article are (a) collecting data of the effects structured physical activity interventions have on validated clinical parameters of IBD and health related symptoms, (b) developing activity recommendations for this clientele. Methods: A scoping review was conducted, searching for relevant articles published until May 2018, which investigated the effects of structured exercise interventions in IBD patients. The heterogeneity of the outcomes and the interventions did not support a quantitative synthesis thus, a qualitative discussion of the studies is provided. Results: After reviewing 353 records, 13 eligible articles were identified. Five studies investigated aerobic exercise, three studies resistance exercise, three studies mind-body therapies and two studies yoga. The quality of the studies is mixed, and the duration is rather short for exercise interventions. Only few studies assessed validated IBD activity markers or inflammatory biomarkers. Nevertheless, the patients showed an increase in fitness, bone mineral density (BMD), quality of life and a decrease of IBD induced stress and anxiety. No severe adversial events were reported. Conclusion: Even though the evidence is limited the application of exercise interventions in IBD patients can be assumed to be safe and beneficial for the patients‘ overall-health, and IBD specific physical and psychosocial symptoms. But there is still a high demand for more thoroughly conducted studies, focussing on important clinical outcome parameters