One of the major subjects of research into crystalline silicon solar cells is their efficiency. It’s widely believed that the absolute limit is that 25% of the solar energy that hits a crystalline cell can be converted to electricity [2].
Researchers are hard at work to reach this efficiency with some companies like Sunpower and Sanyo achieving high efficiencies of up to 24% [4].
The wide spectrum of sun light wavelengths is responsible for the loss of about 70% of the energy that hits the solar cell [2].