The solar panels most familiar to most people are made up of arrays of commercial solar cells or wafers formed of a thin layer of a material such as cadmium telluride or amorphous silicon sprayed or electroplated onto a base such as glass or ceramics. This is the technology most commercial solar kits use. These kinds of solar cells are relatively expensive and not terribly efficient, but that may be changing: Israeli scientists at the University of Tel Aviv claim to have discovered a new method of creating solar cells that will result in costs of less than 1/100th what they have been. According to an article in the EE Times Europe,

The reactive element in the researchers’ patent pending device is genetically engineered proteins using photosynthesis for production of electrical energy.

The scientists applied genetic engineering and nanotechnology for the construction of a hybrid nano — bio, solid state device. According to the researchers, although using photosynthesis for photovoltaic application is not new, their specific technique is the first to enable the production of useful photosynthesis-based photovoltaic cells.

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The researchers suggest existing silicon based photovoltaic cells offer low average energy conversion efficiency of 12-14 percent, while their system is capable of efficiencies of about 25 percent. They based their photovoltaic device on genetically engineered dry proteins photosystem I (PS I), encapsulated in solid state substrate bottom metal and a top transparent electrode.

Another method of lowering the cost and increasing the output of solar cells is to use a fresnel lens as a solar concentrator. Here is a video showing a cheap and efficient homemade fresnel lens concentrator:
Solar Breakthrough