The Development Of The Solar Cell

2023 Author : Hannah Pearcy | [email protected] . Last modified: 2023-06-01 01:49

Convert sunlight directly into electricity - the photovoltaic effect was first experimentally proven by the French physicist Edmond Becquerel. In 1839, the 19-year-old put silver chloride in an acidic solution in his father's laboratory and lit it while platinum electrodes were connected, generating voltage and current.

With selenium and gold to electricity

Based on the Becquerel effect, Charles Fritts developed the first solar cell 45 years later. It consisted of a layer of selenium covered with a thin layer of gold . It had an efficiency of no less than 1%. For a long time, the phenomenon was therefore only used in photodiodes.

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They initially worked in smoke detectors, light meters or infrared receivers , until a larger one was launched into space in 1958 with the Vanguard 1 satellite . On board, the solar cell provided enough energy for seven years to send data to Earth.

Main energy source in space

There were gradual improvements in the 1960s. Up until now, space travel was the only industry that benefited from the best possible and therefore expensive cells and was ready to pay a lot of money for it. There was no reason to invest in cheaper, less efficient solutions.

It was not until the transition from electron tubes to integrated circuits in the 1960s that - thanks to the semiconductor industry - larger crystal ingots were available at lower prices. When their price fell, the price of the solar cells made from them also fell . This reduced cell costs from 1971 to around $ 100 per watt

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Prices are falling and falling

Since 1977, the price per watt has dropped from $ 76 to $ 0.30 in 2015. Today, solar cells are the primary energy source for satellites and probes because they offer the best energy / weight ratio. Photovoltaics is growing fastest in Asia, with China and Japan currently making up half of its worldwide use. The worldwide installed capacity reached around 301 GW in 2016 and grew to 1.3% of the global electricity supply by 2016.

Efficiency is also increasing: Fraunhofer ISE researchers achieved an efficiency of 46% - which means that solar cells are now more efficient than plants .

How do solar cells work?

Photons of sunlight hit the solar panel and are absorbed by semiconductor materials. The electrons are excited. Once excited, an electron can either dissipate the energy as heat and return to its atomic orbital or travel through the PV cell until it reaches an electrode. Current then flows through the material.

The chemical bonds of the material are critical to the functioning of this process , and silicon is usually used in two layers, one layer doped with boron and the other with phosphorus. These layers have different chemical electrical charges and then drive and control the current.

Solar cells connected in series convert solar energy into a usable amount of direct current , which an inverter then converts to alternating current.