Thin film solar cells

The high cost of crystalline silicon wafers (they make up 40-50% of the cost of a finished module) has led the industry to look at cheaper materials to make solar cells.

The selected materials are all strong light absorbers and only need to be about 1micron thick, so materials costs are significantly reduced. The most common materials are amorphous silicon (a-Si, still silicon, but in a different form), or the polycrystalline materials: cadmium telluride (CdTe) and copper indium (gallium) diselenide (CIS or CIGS).

Each of these three is amenable to large area deposition (on to substrates of about 1 meter dimensions) and hence high volume manufacturing. The thin film semiconductor layers are deposited on to either coated glass or stainless steel sheet.

The semiconductor junctions are formed in different ways, either as a p-i-n device in amorphous silicon, or as a hetero-junction (e.g. with a thin cadmium sulphide layer) for CdTe and CIS. A transparent conducting oxide layer (such as tin oxide) forms the front electrical contact of the cell, and a metal layer forms the rear contact.

Thin film technologies are all complex. They have taken at least twenty years, supported in some cases by major corporations, to get from the stage of promising research (about 8% efficiency at 1cm2 scale) to the first manufacturing plants producing early product.

Amorphous silicon is the most well developed of the thin film technologies. In its simplest form, the cell structure has a single sequence of p-i-n layers. Such cells suffer from significant degradation in their power output (in the range 15-35%) when exposed to the sun.

The mechanism of degradation is called the Staebler-Wronski Effect, after its discoverers. Better stability requires the use of a thinner layers in order to increase the electric field strength across the material. However, this reduces light absorption and hence cell efficiency.

This has led the industry to develop tandem and even triple layer devices that contain p-i-n cells stacked one on top of the other. In the cell at the base of the structure, the a-Si is sometimes alloyed with germanium to reduce its band gap and further improve light absorption. All this added complexity has a downside though; the processes are more complex and process yields are likely to be lower.

In order to build up a practically useful voltage from thin film cells, their manufacture usually includes a laser scribing sequence that enables the front and back of adjacent cells to be directly interconnected in series, with no need for further solder connection between cells.

Create suns in a fantasy style. Design your own sun with controls for every part of its appearance, or roll the dice and see what happens.
From modest white dwarfs to red supergiants, you design your own stellar phenomena. You control the coronal flares, diffraction spikes, sun-surface detail, halo and rainbow effects. SolarCell lets you make brilliant stars in impossible colors, or tone down the controls for a more realistic look.
SolarCell's dice button gives you different ready-to-use random effects with one click.

Composite suns into your own backgrounds, or use special image-combining modes to produce eerie results.

Create your own night skies and place false suns into a photograph. Thirty pre-fab settings files get you started fast.

Definition of a Solar Cell - History of Solar Cells

A solar cell is any device that directly converts the energy in light into electrical energy through the process of photovoltaics. The development of solar cell technology begins with the 1839 research of French physicist Antoine-César Becquerel. Becquerel observed the photovoltaic effect while experimenting with a solid electrode in an electrolyte solution when he saw a voltage develope when light fell upon the electrode.

According to Encyclopedia Britannica the first genuine solar cell was built around 1883 by Charles Fritts, who used junctions formed by coating selenium (a semiconductor) with an extremely thin layer of gold.

Russell Ohl - Silicon Solar Cell

Early solar cells, however, had energy conversion efficiencies of under one percent. In 1941, the silicon solar cell was invented by Russell Ohl.
Gerald Pearson, Calvin Fuller and Daryl Chapin - Efficient Solar Cells

In 1954, three American researchers, Gerald Pearson, Calvin Fuller and Daryl Chapin, designed a silicon solar cell capable of a six percent energy conversion efficiency with direct sunlight.
The three inventors created an array of several strips of silicon (each about the size of a razorblade), placed them in sunlight, captured the free electrons and turned them into electrical current. They created the first solar panels. Bell Laboratories in New York announced the prototype manufacture of a new solar battery. Bell had funded the research. The first public service trial of the Bell Solar Battery began with a telephone carrier system (Americus, Georgia) on October 4 1955.

How can I install my system with no upfront costs?

ZERO UP FRONT COSTS. Let us show you how you can install a solar energy system with zero up front costs and significant savings on your energy bill. We can offer you an option of financing the system with a Home Depot Home Improvement Loan. Once qualified, this will allow you to pay for the system costs with a Home Depot Home Improvement Loan, which, at present offers 0% financing for 6 months! Which would allow you to install a solar electric system with no money down and no payment for 6 months.

If you purchase a 3kW system from Solar Cell Sales at the retail costs of $27,000.00 ( system prices may vary), including installation costs. Our company would collect the rebate and you would pay the balance after rebate. Reducing the price of the system to you to around $21,000.00. Additionally, you would collect the $2,000.00 Federal Tax Credit, offered at the present time, further reducing the cost of the system. So, for approximately $19,000.00 you can install a 3 kW solar energy system on your home. Solar energy is considered a home improvement, although your property tax is not increased as a result of this installation, but it can bring the appraisal rate up by about 15%.

How to Convert Solar Energy Into Electricity

Most of the energy on earth comes from the sun. It warms, lights and provides us with nutrients. Clean wind and wave power is nothing but indirect solar energy. Our food supply is based on plants that have captured solar energy through photosynthesis. We, too, can convert this solar energy into an energy that is accessible for our needs.
1
Understand solar energy. Solar energy is heat and light, which has the qualities of waves and individual particles called photons across a vast range of the electromagnetic spectrum. The sun is a nuclear furnace, converting hydrogen to helium through nuclear fusion. The sun releases the energy of 100 billion H-bombs every second. It's a very efficient process, converting mass directly to energy through Albert Einstein's famous equation: E= MC2 where E is energy, M is Mass and C is the speed of light times itself. At 186,000 miles per second light is the fastest speed in the universe. A tiny bit of mass can make a vast amount of energy.
Step
2
Realize how energy is converted. Energy is transformed from one form to another by a device known as a transducer. A microphone converts the sound waves to electricity. To convert solar radiation to electricity we need to start with a solar panel.
Step
3
Look into solar panels. Solar photo voltaic cells (PVC) are essentially semi-conductors, which have electrical transmission properties existing between conductors like metal or salt water and insulators like rubber. Solar panels are constructed with sheets of doped silicon, the primary element in beach sand, with impurities added like phosphorus that allow electrons to flow. When the kinetic solar energy of moving photons hits a PVC, a flow of electrons starts that can be drawn off by a pair of wires, creating direct current (DC) like a battery.
Step
4
Check with your local utility for rebates and with your state government and the federal government for tax breaks. Once you get a clear understanding as to what help is available, do the math. In many states a solar system will pay for itself in a dozen years. In all cases, if you finance a solar installation with a home equity loan, the interest is tax-deductible.
Step
5
Install solar panels in an area, preferably a roof, where they will get the most unobstructed exposure to the sun for most of the year. The best way to do this is to get a reliable solar contractor by referral. In some cases, calling your local utility is a good place to start.
Step
6
Get and install an inverter. Unlike battery power, your house current is alternating, which reverses directing sixty times a second. Before using solar energy to power your appliances, it has to be converted by a device known as an inverter. With most utilities today an inverter will also allow you to feed power back to the electric grid so on a bright sunny day, while you are at work, your electric meter will run backwards.

How many solar cells would I need in order to provide all of the electricity that my house needs?

f you have read the HSW article entitled How Solar Yard Lights Work, then you can get a feeling for how much power a solar cell can produce. The solar panel shown in that article contains 4 cells, and each of them can produce 0.45 volts and 100 milliamps, or 45 milliwatts. Each cell measures 2 inches by 0.5 inches. In other words, with these solar cells you can generate 45 milliwatts in one square inch (6.45 square cm). For the sake of discussion, let's assume that a panel can generate 70 milliwatts per square inch.
To calculate how many square inches of solar panel you need for a house, you need to know:

How much power the house consumes on average.
Where the house is located (so you can calculate mean solar days, average rainfall, etc.). This question is impossible to answer unless you have a specific location in mind. We'll assume that on an average day the solar panels generate their maximum power for 5 hours.
The first question is actually pretty interesting, so let's work on it.
A "typical home" in America can use either electricity or gas to provide heat -- heat for the house, the hot water, the clothes dryer and the stove/oven. If you were to power a house with solar electricity, you would certainly use gas appliances because solar electricity is so expensive. This means that what you would be powering with solar electricity are things like the refrigerator, the lights, the compute r, the TV, stereo equipment, motors in things like furnace fans and the washer, etc. Let's say that all of those things average out to 600 watts on average. Over the course of 24 hours, you need 600 watts * 24 hours = 14,400 watt-hours per day.
From our calculations and assumptions abo ve, we know that a solar panel can generate 70 milliwatts per square inch * 5 hours = 350 milliwatt hours per day. Therefore you need about 41,000 square inches of solar panel for the house. That's a solar panel that measures about 285 square feet (about 26 square meters). That would cost around $16,000 right now. Then, because the sun only shines part of the time, you would need to purchase a battery bank, an inverter, etc., and that often doubles the cost of the installation.

If you want to have a small room air conditioner in your bedroom, double everything.

Because solar electricity is so expensive, you would normally go to great lengths to reduce your electricity consumption. Instead of a desktop computer and a monitor you would use a laptop computer. You would use fluorescent lights instead of incandescent. You would use a small B&W TV instead of a large color set. You would get a small, extremely efficient refrigerator . By doing these things you might be able to reduce your average power consumption to 100 watts. This would cut the size of your solar panel and its cost by a factor of 6, and this might bring it into the realm of possibility.

The thing to remember, however, is that 100 watts per hour purchased from the power grid would only cost about 24 cents a day right now, or $91 a year. That's why you don't see many solar houses unless they are in very remote locations. When it only costs about $100 a year to purchase power from the grid, it is hard to justify spending thousands of dollars on a solar system.

How I built an electricity producing Solar Panel

Several years ago I bought some remote property in Arizona. I am an astronomer and wanted a place to practice my hobby far away from the sky-wrecking light pollution found near cities of any real size. I found a great piece of property. The problem is, it's so remote that there is no electric service available. That's not really a problem. No electricity equals no light pollution. However, it would be nice to have at least a little electricity, since so much of life in the 21st century is dependant on it.

I built a wind turbine to provide some power on the remote property. It works great, when the wind blows. However, I wanted more power, and more dependable power. The wind seems to blow all the time on my property, except when I really need it too. I do get well over 300 sunny days a year on the property though, so solar power seems like the obvious choice to supplement the wind turbine. Solar panels are very expensive though. So I decided to try my hand at building my own. I used common tools and inexpensive and easy to acquire materials to produce a solar panel that rivals commercial panels in power production, but completely blows them away in price. Read on for step by step instructions on how I did it.