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Nanosolar is leading the “Third Wave” of solar power technology: ▪ The First Wave started with the introduction of silicon-wafer based solar cells over three decades ago. While ground-breaking, it is visible until today that this technology came out of a market environment with little concern for cost, capital efficiency, and the product cost / performance ratio. Despite continued incremental improvements, silicon-wafer cells have a built-in disadvantage of fundamentally high materials cost and poor capital efficiency. Because silicon does not absorb light very strongly, silicon wafer cells have to be very thick. And because wafers are fragile, their intricate handling complicates processing all the way up to the panel product. ▪ The Second Wave came about a decade ago with the arrival of the first commercial "thin-film" solar cells. This established that new solar cells based on a stack of layers 100 times thinner than silicon wafers can make a solar cell that is just as good. However, the first thin-film approaches were handicapped by two issues: 1. The cell's semiconductor was deposited using slow and expensive high-vacuum based processes because it was not known how to employ much simpler and higher-yield printing processes (and how to develop the required semiconductor ink). 2. The thin films were deposited directly onto glass as a substrate, eliminating the opportunity of ▪ using a conductive substrate directly as electrode (and thus avoiding bottom-electrode deposition cost), ▪ achieving a low-cost top electrode of high performance, ▪ employing the yield and performance advantages of individual cell matching & sorting, ▪ employing high-yield continuous roll-to-roll processing, and ▪ developing high-power high-current panels with lower balance-of-system cost. ▪ The Third Wave of solar power consists of companies addressing the above shortcomings and opportunities. Most every of the new companies address one or the other of the above aspects. One company -- Nanosolar -- brings together the entire conjunction of all seven areas of innovation, each break-through in their own right, to deliver a dramatic improvement in the cost-efficiency, yield, and throughput of the production of much thinner solar cells. At Nanosolar, we have taken the highest-performance and most durable photovoltaic thin-film semiconductor, called CIGS (for "Copper Indium Gallium Diselenide"), and innovated on all seven critical areas necessary to reach a breakthrough cost reduction in solar cells, panels, and systems. As opposed to using slow and expensive high-vacuum based thin-film deposition processes, we developed a proprietary ink (1) to allow us to use much simpler and higher-yield printing (2) for depositing the solar cell's semiconductor. We use a highly conductive yet low-cost foil as a substrate (3), which allows us to avoid the need to separately deposit an expensive bottom electrode layer (as required for a non-conductive substrate such as glass). The foil furthermore allows us to ▪ apply the superior economics of high-yield continuous roll-to-roll processing (4), ▪ achieve a lower-cost high-performance top electrode (5), ▪ assemble cells by individually matched electrical characteristics (6), and ▪ develop high-power high-current panels (7) with lower balance-of-system cost. The result sets the standard for cost-efficient solar electricity. Leveraging recent science advances in nanostructured materials, Nanosolar has developed a proprietary ink that makes it possible to simply print the semiconductor of a high-performance solar cell. This ink is based on Nanosolar developing various proprietary forms of nanoparticles and associated organic dispersion chemistry and processing techniques suitable for delivering a semiconductor of high electronic quality. A key advantage of the ink is specific to an idiosyncracy of the CIGS semiconductor: Because it consists of four elements which have to be in just the right atomic ratios to each other, the ink serves a useful purpose by effectively "locking in" a uniform distribution ("by design"). The homogeneous mix of nanoparticles in the ink in just the right overall amounts ensures that the atomic ratios of the four elements are correct wherever the ink is printed, even across large areas of deposition. This contrasts to vacuum deposition processes where, due to the four-element nature of CIGS, one effectively has to "atomically" synchronize various materials sources -- a challenge with no successful precedent in any industry on a repeatable high-yield production-scale basis. Printing is by far the simplest, highest-yield, and most capital-efficient technique for depositing thin films. Printing is extremely fast; the equipment involved is easy to use and maintain; and it works in plain air (no vacuum chamber required). Another key advantage of a printable CIGS ink is that one can print it just where one wants it to be, achieving high materials utilization of the semiconductor material. Printing is much simpler and more robust than vacuum deposition techniques such as sputtering or evaporation which have conventionally been used to fabricate thin-film solar cells; the process cost of vacuum techniques is so high that the result is not an inexpensive cell relative to the per-square-meter economics that the solar industry requires. Nanosolar is the first and so far only company in the world that has managed to make efficient solar cells work on a metal foil substrate that is both low cost and highly conductive. Our metal foil has a conductivity that is more than 20 times higher than that of the stainless steel used by others -- and thus enables major cost reduction on the solar cell's thin-film bottom electrode. Note that a thin-film solar cell consists most fundamentally of an absorber layer (the semiconductor) sandwiched in between a top and a bottom electrode layer. If the thin films of a solar cell are deposited directly onto a highly conductive metal foil (as opposed to glass or stainless steel), then the bottom electrode gets much simpler because the substrate can do the job of carrying the current. Roll-to-roll processing is the manufacturing implementation framework of choice for any product with very low cost required per large areas of deposition. Rolls that are meters wide and miles long can be processed efficiently with very high throughput (and thus minimal capital cost) in equipment with a very small footprint. A key advantage of roll-to-roll processing is that after the first few meters of initializing a new roll, the whole process hits a steady state which can then be maintained for the entire rest of the roll, resulting in very uniform deposition process parameters applied to essentially the entire (foil) substrate. This is much better than processing wafers or glass plates, which have to be moved in and out of each process station individually, introducing undesirable start-up and move-out process state variability (and cycle time cost). Edge effects are also greatly minimized in roll processing (whereas processing glass plates or wafers requires much work and capital dealing with uniformity issues at the edges of the substrate). Nanosolar has developed a fundamental innovation on its solar cells' top electrode (not shown below) which has two major benefits: It supports an entire order of magnitude higher current than any past or present thin-film solar product known; and it is very low cost. Note that obtaining a good top electrode is challenging because it has to be both transparent and conductive. With conventional silicon solar technology, individual wafer cells are sorted into performance bins before the cells are assembled into panels. This ensures that each panel produced contains cells with matched electrical characteristics. Nanosolar's approach combines the advantages of thin films with the power of electrically matched cells, resulting in better panel efficiency distribution and yield. Note that with conventional thin-film-on- glass solar technology, cell sorting and matching is not possible because cell transitions are created through scribing after they are already deposited on the glass substrate. But since each cell has somewhat different electrical characteristics, a thin-film-on-glass panel consists of cells that may not be well-matched. It turns out that the effect of electrical mismatch per cell leads to exponentially greater losses per panel as a result, and panel yield and efficiency distribution suffer: A bad cell results in a bad panel with thin-film-on-glass technology; but with a cell-sorting technology, only that cell will be a loss. The value impact of that difference is staggering: If a panel contains 100 cells, sorted-cell assembly lowers the yield-loss cost of a bad cell to 1/100th compared to monolithic cell integration. Based on our cell and product design innovations, Nanosolar is capable of delivering high-power solar panels with 5-10 times higher current than other thin-film solar panels on the market today. This has enabled us to work with our partners and customers to dramatically reduce the balance-of-system cost involved in deploying solar electricity systems. The amount of current that a panel can support is important because current capacity limitations negatively impact balance-of-system cost and thus power economics "That's impossible" is a good foundation for fundamental intellectual property -- especially if that statement comes from a leading domain expert -- yet one has already made it happen. Nanosolar engineers and scientsts have produced such progress in an entire array of technology areas. Nanosolar owns the definitive portfolio of intellectual property with respect to the world’s most cost-efficient solar electricity products, specifically thin-film solar cells that can be produced with very high throughput. Nanosolar has over 180 patents issued, licensed, or pending regarding all critical aspects of nanostructured materials, solar-cell technology, cost-efficient high-throughput processing, and relevant product and equipment designs.

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