Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

2 1 The innovative transport systems and the CityMobil project 10 1.1 The research questions 10 2 The state of art in the field of automatic transport systems 12 2.1 Case studies and demand studies for innovative transport systems 12 3 The design and implementation of surveys 14 3.1 Definition of experimental design 14 3.2 Questionnaire design and delivery 16 3.3 First analyses on the collected sample 18 4 Calibration of Logit Multionomial demand models 21 4.1 Methodology 21 4.2 Calibration of the “full” model. 22 4.3 Calibration of the “final” model 24 4.4 The demand analysis through the final Multinomial Logit model 25 5 The analysis of interaction between the demand and socioeconomic attributes 31 5.1 Methodology 31 5.2 Application of Mixed Logit models to the demand 31 5.3 Analysis of the interactions between demand and socioeconomic attributes through Mixed Logit models 32 5.4 Mixed Logit model and interaction between age and the demand for the CTS 38 5.5 Demand analysis with Mixed Logit model 39 6 Final analyses and conclusions 45 6.1 Comparison between the results of the analyses 45 6.2 Conclusions 48 6.3 Answers to the research questions and future developments 52

The European commission

A dye that both maximizes electrolyte compatibility and improves light-harvesting properties has been designed for dye-sensitized solar cells. In cells based on the cobalt(II)/(III) redox mediator, use of the dye resulted in a power-conversion efficiency of 13%, revealing the great potential of porphyrin dyes for future solar cell applications.

/pdf/dye-sensitized-solar-cells-with-13-efficiency-achieved-1uicqd6iq9.pdf

Dye-sensitized solar cells with 13% efficiency achieved through the molecular engineering of porphyrin sensitizers

Solar cells are attractive candidates for clean and renewable power; with miniaturization, they might also serve as integrated power sources for nanoelectronic systems. The use of nanostructures or nanostructured materials represents a general approach to reduce both cost and size and to improve efficiency in photovoltaics. Nanoparticles, nanorods and nanowires have been used to improve charge collection efficiency in polymer-blend and dye-sensitized solar cells, to demonstrate carrier multiplication, and to enable low-temperature processing of photovoltaic devices. Moreover, recent theoretical studies have indicated that coaxial nanowire structures could improve carrier collection and overall efficiency with respect to single-crystal bulk semiconductors of the same materials. However, solar cells based on hybrid nanoarchitectures suffer from relatively low efficiencies and poor stabilities. In addition, previous studies have not yet addressed their use as photovoltaic power elements in nanoelectronics. Here we report the realization of p-type/intrinsic/n-type (p-i-n) coaxial silicon nanowire solar cells. Under one solar equivalent (1-sun) illumination, the p-i-n silicon nanowire elements yield a maximum power output of up to 200 pW per nanowire device and an apparent energy conversion efficiency of up to 3.4 per cent, with stable and improved efficiencies achievable at high-flux illuminations. Furthermore, we show that individual and interconnected silicon nanowire photovoltaic elements can serve as robust power sources to drive functional nanoelectronic sensors and logic gates. These coaxial silicon nanowire photovoltaic elements provide a new nanoscale test bed for studies of photoinduced energy/charge transport and artificial photosynthesis, and might find general usage as elements for powering ultralow-power electronics and diverse nanosystems.

http://www.eecs.umich.edu/zhonglab/pub/NW_Solar_Lieber.pdf

Coaxial silicon nanowires as solar cells and nanoelectronic power sources

Metal halide perovskite photovoltaic cells could potentially boost the efficiency of commercial silicon photovoltaic modules from ∼20 toward 30% when used in tandem architectures. An optimum perovskite cell optical band gap of ~1.75 electron volts (eV) can be achieved by varying halide composition, but to date, such materials have had poor photostability and thermal stability. Here we present a highly crystalline and compositionally photostable material, [HC(NH2)2](0.83)Cs(0.17)Pb(I(0.6)Br(0.4))3, with an optical band gap of ~1.74 eV, and we fabricated perovskite cells that reached open-circuit voltages of 1.2 volts and power conversion efficiency of over 17% on small areas and 14.7% on 0.715 cm(2) cells. By combining these perovskite cells with a 19%-efficient silicon cell, we demonstrated the feasibility of achieving >25%-efficient four-terminal tandem cells.

http://science.sciencemag.org/content/sci/351/6269/151.full.pdf

A mixed-cation lead mixed-halide perovskite absorber for tandem solar cells

Fourier Transform Photocurrent Spectroscopy (FTPS) has been used for a fast and sensitive quality assessment of photovoltaic thin films, such as the microcrystalline silicon. Because the properties of this material strongly depend on the substrate used, we demonstrate here how to utilize the FTPS for measurement of films grown on conductive TCO covered glass substrate, as it is the case of solar cells. Further, we have studied homogeneity of the optoelectronic properties of layers over large areas (30/spl times/30 cm/sup 2/) and for one case correlated the results with the cell efficiency over the area. Moreover, we show a possibility to interpret the FTPS data on cells as the quantum efficiency (spectral response) measurement and to extend the measuring range from near IR over the whole visible region.

Fast and sensitive defect characterization and spectral response measurement of thin film silicon solar structures

Image and particle sensors based on thin film on CMOS (TFC) technology, where a-Si:H detectors are vertically integrated on top of a CMOS chip, basically provide high sensitivity and low dark current densities (Jdark). However, as shown in previous work and as confirmed by the actual measurements, Jdark values depend on the topology of the chip and on the detector structure used. The present paper describes a systematic study carried out, both with test structures on glass and also with a dedicated CMOS test chip designed by CERN. The increase in Jdark is shown to be related to border effects, and especially on the detailed structure of the pixel periphery. In all cases, lower Jdark are obtained when one uses metal-i-p instead of n-i-p configuration detectors. Transferring these results to the standard TFC sensors used by them, the authors have obtained values of Jdark as low as 20 pA/cm2 at -1 V reverse bias.

Influence of design parameters on dark current of vertically integrated a-Si:H diodes.

A series of extensively characterized films of hydrogenated amorphous silicon (a-Si:H) has been used to study influences on and the reliability of the measurement of minority carrier diffusion length by the surface photovoltage method (SPV). The films were prepared by high-rate VHF glow-discharge deposition at plasma excitation frequencies f between 38 to 145 MHz. Defect density ND and Urbach tail parameter Eo, measured by photothermal deflection spectroscopy (PDS), and photoluminescence (PL) yield at 4.2 K do not change as a function of f. However, photoconductivity, open-circuit voltage of Schottky barrier structures and diffusion length decrease with f. The increasing dark conductivity activation energy Ea shows that the films become more intrinsic with increasing f. Therefore basic assumptions of the conventional SPV theory, like the existence of a field-free region, may be violated. We discuss whether drift and diffusion of holes and electrons contribute to the SPV signal. We also show how the power law governing the relation between photocurrent and light intensity can change the SPV result.

Measurement of surface photovoltage in high-rate deposited a-Si:H films and comparison with photothermal deflection spectroscopy and conductivity data

Note: IMT-NE Number: 475 Reference PV-LAB-ARTICLE-2007-002 Record created on 2009-02-10, modified on 2017-05-10

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S1946427400034345

Transient Current Behavior of Vertically Integrated Amorphous Silicon Diodes

Thin-film Si solar module production requires a fast wide area tool for layer characteristic measurement and control. Non-uniformity in layer deposition is expected to induce loss in module power. Simulations of amorphous Si modules using a two-dimensional model have been used to examine the efficiency loss associated with non uniformity of large scale monolithically integrated thin film modules. The results indicate that non uniform deposition significantly lowers the module efficiency, in a magnitude that varies depending on the shape and orientation of the deposition signature relative to the scribe lines. In order to control the deposition process of individual layers in layer stacks in thin-film PV modules a wide area metrology tools has been developed and tested. Example of layers maps obtained during production of Si layers module are shown. Comparisons of layer characteristics obtained using this tool and values obtained by conventional methods are given to validate the tool performances.

Nicolas Wyrsch

Papers

Fast and sensitive defect characterization and spectral response measurement of thin film silicon solar structures

Influence of design parameters on dark current of vertically integrated a-Si:H diodes.

Measurement of surface photovoltage in high-rate deposited a-Si:H films and comparison with photothermal deflection spectroscopy and conductivity data

Transient Current Behavior of Vertically Integrated Amorphous Silicon Diodes

NEW PARADIGM FOR REAL-TIME MEASUREMENT AND MAPPING IN a-Si:H/uc-Si:H TANDEM DEVICES