Here is a low power low efficiency photovoltaic cell that you can make you own in the kitchen
with materials from the hardware store.
This cell is made from cuprous oxide instead of silicon and you can build a working solar cell in 2 hours
to build it i follow this instruction: http://scitoys.com/scitoys/scitoys/echem/echem2.html
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Step 1: Materials You Will Need

A sheet of copper flashing from the hardware store
A transparent CD case
Electric wire
Sodium bicarbonate or Table salt

An electric stove
hot glue
solder
Sheet metal shears for cutting the copper sheet

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Step 2: How to Prepare Copper

The first step is to cut a piece of the copper sheeting that is about the size of the burner on the stove. Wash your hands so they don't have any grease or oil on them. Then wash the copper sheet with soap or cleanser to get any oil or grease off of it. Use the sandpaper or wire brush to thoroughly clean the copper sheeting, so that any sulphide or other light corrosion is removed.

Next, place the cleaned and dried copper sheet on the burner and turn the burner to its highest setting.

Step 3: Cooking the Copper

cook the copper for at least 30 min.
As the copper gets hotter, the colors are replaced with a black coating of cupric oxide. This is not the oxide we want, but it will flake off later, showing the reds, oranges, pinks, and purples of the cuprous oxide layer underneath.
The last bits of color disappear as the burner starts to glow red.
When the burner is glowing red-hot, the sheet of copper will be coated with a black cupric oxide coat. Let it cook for a half an hour, so the black coating will be thick. This is important, since a thick coating will flake off nicely, while a thin coat will stay stuck to the copper.
After the half hour of cooking, turn off the burner. Leave the hot copper on the burner to cool slowly. If you cool it too quickly, the black oxide will stay stuck to the copper.

Step 4: Prepare the Cooked Copper

When the copper has cooled to room temperature (this takes about 20 minutes), most of the black oxide will be gone. A light scrubbing with your hands under running water will remove most of the small bits. Resist the temptation to remove all of the black spots by hard scrubbing or by flexing the soft copper. This might damage the delicate red cuprous oxide layer we need to make to solar cell work.
When you are finished cleaning the copper should be as in the photo

Step 5: Assemble the Cell

Cut another sheet of copper ,
Solder a wire to each copper plate
glue to insulate the soldering
glue the plate as in photo

Step 6: Fill and Seal the Cell

seal the cell and fill it with a solution of baking soda (or cooking salt) and water

Step 7: Test the Cell

test the cell whit Sunlight
A note about power

my cell produces 58 microamps at 0.10 volts.

Don't expect to light light bulbs or charge batteries with this device. It can be used as a light detector or light meter, but it would take acres of them to power your house.