Photovoltaic (Solar Cells) - pin mat troi

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Photovoltaic (Solar Cells) - pin mat troi

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Photovoltaic (Solar Cells) - pin mat troi

Ø II Chap : Photovoltaic (Solar Cells) O00 onoonoo00 @ Introduction I The history of photovoltaics goes back to the year 1839, when Becquere discovered the photovoltaic effect, but no technology was available in the 19t century to exploit this discovery The semiconductor age only began about 100 years later After Shockley had developed a model for the pn junction, Bell Laboratories produced the first solar cell in 1954; the efficiency of this, in converting light into electricity, was about 5% Photovoltaics offers the highest versatility among renewable energy technologies Theoretically, PV systems could cover the whole electricity demand of most countries in the world i CĐ rm 2/70 @ Tntroduction I Worldwide, the installed photovoltaics capacity and the share of electricity generated by PV are still low, despite impressive market growth The political environment and magnitude of market introduction programmes will determine the future of this technology 3/70 @ The photo effect Light, with its photon energy, can provide the energy to lift an electron to a higher orbit The photon energy is given by: h:c E= ` L The energy sufficient to lift the electron to orbit E is also called the ionization energy (external photoelectric effect) photovoltaic cells mainly convert to electricity photons of visible, ultraviolet and infrared light, therefore, the internal photo effect determines the effect of light in a solar cell [IIIIIIIIII I € The photo effect I The highest fully occupied band is called the valence band The next highest band, which can be partially occupied or totally empty, is called the conduction band The space between VB and CB is called the forbidden band The energy gap between the band is called the band gap Conductor band (CB CB CB Forbidden band (FB) VB ẬP.

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