Solar panels collect the light that hits the earth from the sun. They convert the light into power that is either stored in batteries or used straight away, for example a toy car or desktop gadget.
Solar lights use the power from the batteries that the solar panel has collected during the day. They typically use LED bulbs to provide light as these are the most efficient way of converting the power back into light.
Solar products more often then not have batteries to store the power collected during the day for use later when required. Solar Lights are probably the best example of this, other notable product types include solar phone chargers.
Think about rain falling on two buckets placed side by side. A bigger bucket will collect more water then a smaller bucket from the same length of time in the rain.
Check out this guide to getting the best from your solar powered products.