HISTORY OF PHOTO VOLTAIC CELLS

With all the current media coverage of climate change and our growing anxieties surrounding emissions and carbon footprints, you would be forgiven for thinking that renewable energy systems like photovoltaic panels are new innovations developed to tackle the modern environmental challenges we face.

In fact, human beings have long been fascinated by the idea of harnessing the sun'senergy, and we have been experimenting with technology to do this for thousands of years.

The ancient Greeks, including the legendary inventor Archimedes, experimented with using giant mirrors to take advantage of the sun's heat as a weapon of war. But it wasn't until 19th century, with the discovery of the 'photovoltaic effect', that what we would commonly recognise as the solar panel was born.

The photovoltaic effect is the creation of a voltage in a material which has been exposed to light, and was first recognised by the French physicist A. E. Becquerel in 1839. Becquerel was not able to make practical use of this discovery, but his work influenced Charles Fritts, who in 1883 built the world's first solar cell.

Fritts' cell used a semiconductor and an extremely thin layer of gold, and was a big scientific step forward at the time, despite being only around 1% efficient.

The modern photovoltaic cell, which was far more efficient than its 19th century predecessors, was created by Bell Laboratories in 1954. At first, there was no real demand for the product, as it was much costlier than other forms of electricity generation.

However, in the 1960s an ideal use was found for photovoltaic cells. They were fitted by NASA onto satellites bound for outer space, as this would enable the crafts to continue generating power even after their batteries had run out.

During the following decade or so, solar panels became widely in demand in other specialist markets such as offshore oil platforms, which were difficult to supply with power by other means.

In the later part of the 20th century the domestic solar energy consumer was born, as people began to realise they could not simply rely on cheap oil and other fossil fuels indefinitely. High oil prices caused by conflicts in the Middle East, along with a growing awareness of environmental issues, led to many homeowners adopting solar energy as a way to become more self-sufficient and less detrimental to the planet..

Today, there are two main kinds of solar energy systems used by homeowners. One is the basic photovoltaic conversion variety, which uses panels to generate electricity directly using the sun's energy.

The other type is thermal solar power, which uses the sun's energy to heat up special fluids travelling through pipes, which can then be used heat up water or power machinery.

Despite this long history of experimentation and innovation, solar power is still far from being exploited as much as it could be. If we truly want a sustainable, greener future for our planet, then solar photovoltaic technology is going to have to be given a major role to play in it.