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

Ju Mei,†,‡,∥ Nelson L. C. Leung,†,‡,∥ Ryan T. K. Kwok,†,‡ Jacky W. Y. Lam,†,‡ and Ben Zhong Tang*,†,‡,§ †HKUST-Shenzhen Research Institute, Hi-Tech Park, Nanshan, Shenzhen 518057, China ‡Department of Chemistry, HKUST Jockey Club Institute for Advanced Study, Institute of Molecular Functional Materials, Division of Biomedical Engineering, State Key Laboratory of Molecular Neuroscience, Division of Life Science, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China Guangdong Innovative Research Team, SCUT-HKUST Joint Research Laboratory, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou 510640, China

Aggregation-Induced Emission: Together We Shine, United We Soar!

Recent startling interest for lanthanide luminescence is stimulated by the continuously expanding need for luminescent materials meeting the stringent requirements of telecommunication, lighting, electroluminescent devices, (bio-)analytical sensors and bio-imaging set-ups. This critical review describes the latest developments in (i) the sensitization of near-infrared luminescence, (ii) “soft” luminescent materials (liquid crystals, ionic liquids, ionogels), (iii) electroluminescent materials for organic light emitting diodes, with emphasis on white light generation, and (iv) applications in luminescent bio-sensing and bio-imaging based on time-resolved detection and multiphoton excitation (500 references).

/pdf/lanthanide-luminescence-for-functional-materials-and-bio-1w9cppwf8r.pdf

Lanthanide luminescence for functional materials and bio-sciences

What Video Games Have to Teach Us about Learning and Literacy

The efficiency of silicon solar cells has a large influence on the cost of most photovoltaics panels. Here, researchers from Kaneka present a silicon heterojunction with interdigitated back contacts reaching an efficiency of 26.3% and provide a detailed loss analysis to guide further developments.

Silicon heterojunction solar cell with interdigitated back contacts for a photoconversion efficiency over 26

Enhancing the performance of solar cells via luminescent down-shifting of the incident spectrum: A review

Rubidium (Rb) is explored as an alternative cation to use in a novel multication method with the formamidinium/methylammonium/cesium (Cs) system to obtain 1.73 eV bangap perovskite cells with negligible hysteresis and steady state efficiency as high as 17.4%. The study shows the beneficial effect of Rb in improving the crystallinity and suppressing defect migration in the perovskite material. The light stability of the cells examined under continuous illumination of 12 h is improved upon the addition of Cs and Rb. After several cycles of 12 h light–dark, the cell retains 90% of its initial efficiency. In parallel, sputtered transparent conducting oxide thin films are developed to be used as both rear and front transparent contacts on quartz substrate with less than 5% parasitic absorption of near infrared wavelengths. Using these developments, semi-transparent perovskite cells are fabricated with steady state efficiency of up to 16.0% and excellent average transparency of ≈84% between 720 and 1100 nm. In a tandem configuration using a 23.9% silicon cell, 26.4% efficiency (10.4% from the silicon cell) in a mechanically stacked tandem configuration is demonstrated which is very close to the current record for a single junction silicon cell of 26.6%.

Rubidium Multication Perovskite with Optimized Bandgap for Perovskite-Silicon Tandem with over 26% Efficiency

A surface texture enhances the capacity of a solar cell to absorb incident radiation. In high efficiency and industry standard designs alike, pyramidal surface textures play the key role of reducing the reflectance of the cell surface. This reduction is achieved by ensuring that incident light rays suffer at least a double reflection in the various facets of the structure. In this work, we define a general expression for the reflectance of a pyramidal texture by identifying discrete paths of reflection and the fraction of reflected light that follows each of these paths. We apply the expression to analyse the reflection of normally incident light at textured surfaces. We examine three common morphologies, finding that a regular array of inverted pyramids just outperforms a random array of upright pyramids, with a regular array of upright pyramids showing poorer capacity to reduce front surface reflection. We extend the analysis to determine the transmittance of the various structures, thus permitting the calculation of a figure of merit that can be used to optimise the thickness of antireflection coatings (ARCs). Finally, by examining the angles at which light is reflected by the pyramidal textures, we find that an encapsulant of refractive index greater than 1.59 gives between 79 and 92% of the initially reflected light a second chance to enter the solar cell.

Reflection of normally incident light from silicon solar cells with pyramidal texture

A solar cell that is readily manufactured using processing techniques which are less expensive than microelectronic circuit processing. In preferred embodiments, printing techniques are utilized in selectively forming masks for use in etching of silicon oxide and diffusing dopants and in forming metal contacts to diffused regions. In a preferred embodiment, p-doped regions and n-doped regions are alternately formed in a surface of the wafer through use of masking and etching techniques. Metal contacts are made to the p-regions and n-regions by first forming a seed layer stack that comprises a first layer such as aluminum that contacts silicon and functions as an infrared reflector, second layer such titanium tungsten that acts as diffusion barrier, and a third layer functions as a plating base. A thick conductive layer such as copper is then plated over the seed layer, and the seed layer between plated lines is removed. A front surface of the wafer is preferably textured by etching or mechanical abrasion with an IR reflection layer provided over the textured surface. A field layer can be provided in the textured surface with the combined effect being a very low surface recombination velocity.

Solar cell and method of manufacture

The freeware program OPAL 2 computes the optical losses associated with the front surface of a Si solar cell. It calculates the losses for any angle of incidence within seconds, where the short computation time is achieved by decoupling the ray tracing from the Fresnel equations. Amongst other morphologies, OPAL 2 can be used to assess the random-pyramid texture of c-Si solar cells, or the ‘isotexture’ of mc-Si solar cells, and to determine (i) the optimal thickness of an antireflection coating with or without encapsulation, (ii) the impact of imperfect texturing, such as non-ideal texture angles, over-etched isotexture, and flat regions, and (iii) the subsequent 1D generation profile in the Si. This paper describes the approach and assumptions employed by OPAL 2 and presents examples that demonstrate the dependence of optical losses on texture quality and incident angle.

Keith R. McIntosh

Papers

Enhancing the performance of solar cells via luminescent down-shifting of the incident spectrum: A review

Rubidium Multication Perovskite with Optimized Bandgap for Perovskite-Silicon Tandem with over 26% Efficiency

Reflection of normally incident light from silicon solar cells with pyramidal texture

Solar cell and method of manufacture

OPAL 2: Rapid optical simulation of silicon solar cells