Reported are the development and demonstration of a 17% efficient 25mm x 25mm crystalline Silicon solar cell and a 16% efficient 125mm x 125mm crystalline Silicon solar cell, both produced by Ink-jet printing Silicon Ink on a thin crystalline Silicon wafer. To achieve these objectives, processing approaches were developed to print the Silicon Ink in a predetermined pattern to form a high efficiency selective emitter, remove the solvents in the Silicon Ink and fuse the deposited particle Silicon films. Additionally, standard solar cell manufacturing equipment with slightly modified processes were used to complete the fabrication of the Silicon Ink high efficiency solar cells. Also reported are the development and demonstration of a 18.5% efficient 125mm x 125mm monocrystalline Silicon cell, and a 17% efficient 125mm x 125mm multicrystalline Silicon cell, by utilizing high throughput Ink-jet and screen printing technologies. To achieve these objectives, Innovalight developed new high throughput processing tools to print and fuse both p and n type particle Silicon Inks in a predetermined pat-tern applied either on the front or the back of the cell. Additionally, a customized Ink-jet and screen printing systems, coupled with customized substrate handling solution, customized printing algorithms, and a customized ink drying process, in combination with a purchased turn-key line, were used to complete the high efficiency solar cells. This development work delivered a process capable of high volume producing 18.5% efficient crystalline Silicon solar cells and enabled the Innovalight to commercialize its technology by the summer of 2010.

Reported are the development and demonstration of a 17% efficient 25mm x 25mm crystalline silicon solar cell and a 16% efficient 125mm x 125mm crystalline silicon solar cell, both produced by ink-jet printing Silicon Ink on a thin crystalline silicon wafer. To achieve these objectives, processing approaches were developed to print the Silicon Ink in a predetermined pattern to form a high efficiency selective emitter, remove the solvents in the Silicon Ink and fuse the deposited particle silicon films. Additionally, standard solar cell manufacturing equipment with slightly modified processes were used to complete the fabrication of the Silicon Ink high efficiency solar cells. Also reported are the development and demonstration of an 18.5% efficient 125mm x 125mm monocrystalline silicon cell, and a 17% efficient 125mm x 125mm multicrystalline silicon cell, by utilizing high throughput ink-jet and screen printing technologies. To achieve these objectives, Innovalight developed new high throughput processing tools to print and fuse both p and n type particle Silicon Inks in a predetermined pattern applied either on the front or the back of the cell. Additionally, customized ink-jet and screen printing systems, coupled with customized substrate handling solution, customized printing algorithms, and a customized ink drying process, in combination with a purchased turn-key line, were used to complete the high efficiency solar cells.

The world of today must face up to two contradictory energy problems: on the one hand, there is the sharply growing consumer demand in countries such as China and India. On the other hand, natural resources are dwindling. Moreover, many of those countries which still possess substantial gas and oil supplies are politically unstable. As a result, renewable natural energy sources have received great attention. Among these, solar-cell technology is one of the most promising candidates. However, there still remains the problem of the manufacturing costs of such cells. Many attempts have been made to reduce the production costs of “conventional” solar cells (manufactured from monocrystalline silicon using diffusion methods) by instead using cheaper grades of silicon, and simpler pn-junction fabrication. That is the ‘hero’ of this book; the heterojunction solar cell.

The overall goal of this research is to improve fundamental understanding of the hydrogen passivation of defects in low-cost silicon and the fabrication of high-efficiency solar cells on thin crystalline silicon through low-cost technology development. A novel method was developed to estimate the flux of hydrogen, released from amorphous silicon nitride film, into the silicon. Rapid-firing-induced higher flux of hydrogen was found to be important for higher defect passivation. This was followed by the fabrication of solar cell efficiencies of ~ 17% on low-cost, planar cast multicrystalline silicon. Solar cell efficiencies and lifetime enhancement in the top, middle, and bottom regions of cast multicrystalline silicon ingots were explained on the basis of impurities and defects generally found in those regions. In an attempt to further reduce the cost, high-efficiency solar cells were fabricated on thin crystalline silicon wafers with full area aluminum-back surface field. In spite of loss in efficiency, wafer thinning reduced the module cost. Device modeling was performed to establish a roadmap towards high-efficiency thin cells and back surface recombination velocity and back surface reflectance were identified as critical parameters for high-efficiency thin cells. Screen-printed solar cells on float zone material, with efficiencies> 19% on 300 Îơm and> 18% on 140 Îơm were fabricated using a novel low-cost fabrication sequence that involved dielectric rear passivation along with local contacts and back surface field.

Crystalline silicon thin-film solar cells have the potential to drastically reduce the cost for silicon solar cells. The aim of the work described in this book was to improve the quality of thin silicon layers on foreign substrates and to apply the experience gained hereby to various low-cost substrates. Two aspects of the crystalline silicon thin-film solar cell were examined intensively to reach this goal: diffusion barrier properties of common intermediate layers, and zone-melting recrystallisation of silicon layers. For investigation of diffusion barrier layers, the focus was set to diffusion of the transition metals iron, chromium and vanadium in the intermediate layer materials SiO2 and SiNx deposited by plasma-enhanced chemical vapour deposition. Temperatures ranging from 900C to 1350C were applied to the samples. Zone-melting recrystallisation of silicon is an important technique to prepare large crystal grains of several millimetres width and several centimetres length on amorphous substrates. Parameter studies on SiO2-capped multicrystalline silicon wafers were done to investigate the effect of the so-called supercooled zone on crystal quality. One-side contacted solar cells were prepared on optimised layers on such model substrates. For the first time, also low-cost ribbon silicon and ceramics (SiSiC, Si3N4, SiAlON, mullite) were tested as substrate material. Cell efficiencies up to 10.5% could be obtained when using these materials. The author: Dr. Stefan Reber studied Physics at the Technical University of Darmstadt, Germany. He joined the solar cell department of the Fraunhofer Institute for Solar Energy Systems for his Ph.D. thesis, where he was in charge of improving crystalline silicon thin-film solar cells on foreign substrates.

The scientific community and industry have seen tremendous progress in efficient energy production and storage in the last few years. With the advancement in technology, new devices require high-performance, stretchable, bendable, and twistable energy sources, which can be integrated into next-generation wearable, compact, and portable electronics for medical, military, and civilian applications. Smart and Flexible Energy Devices examines the materials, basic working principles, and state-of-the-art progress of flexible devices like fuel cells, solar cells, batteries, and supercapacitors. Covering the synthesis approaches for advanced energy materials in flexible devices and fabrications and fundamental design concepts of flexible energy devices, such as fuel cells, solar cells, batteries, and supercapacitors, top author teams explore how newer materials with advanced properties are used to fabricate the energy devices to meet the future demand for flexible electronics. Additional features include: • Addressing the materials, technologies, and challenges of various flexible energy devices under one cover • Emphasizing the future demand and challenges of the field • Considering all flexible energy types, such as fuel cells, solar cells, batteries, and supercapacitors • Suitability for undergraduate and postgraduate students of material science and energy programs This is a valuable resource for academics and industry professionals working in the field of energy materials, nanotechnology, and energy devices.