Slide 1
Absorbed light creates mobile electrons and holes
A solar cell absorbs suitable photons, packets of light, in a semiconductor. Their energy can create mobile electrons and holes: gaps where electrons are missing.
More to Read
A hole represents the absence of an electron in a state that can otherwise be occupied. Both carrier types participate in electrical behaviour, rather than the cell merely ejecting electrons into empty space.
Slide 2
The junction helps separate those charge carriers
A semiconductor junction establishes conditions that separate generated carriers. Contacts then connect the cell to an external circuit.
More to Read
Without effective collection, electrons and holes can recombine before delivering useful energy. Material quality and device geometry therefore matter after light has already been absorbed.
Slide 3
Some incoming light cannot become useful electricity
Photons with unsuitable energy may pass through or lose part of their energy as heat. Reflection and recombination create further limits.
More to Read
A semiconductor’s band gap sets an important energy scale for absorption. Choosing it involves a tradeoff between using more of the spectrum and obtaining useful voltage from collected carriers.
Slide 4
The load selects a point on the current–voltage curve
A cell has a current–voltage relationship rather than one fixed power output. Electronics can operate it near a useful maximum-power point.
More to Read
Temperature and illumination change that relationship. A panel rated under standard test conditions may deliver a different output in heat, shade or changing sunlight without being defective.
Slide 5
Modules, protection and an inverter form a wider system
Cells form modules and arrays, while other components support, protect and connect them. An inverter can convert their direct-current output into alternating current.
More to Read
Shading one part of a series-connected group can affect more than that small area. Bypass paths and layout help manage mismatch, illustrating why module and system design influence harvested energy.
Sources
- Solar Photovoltaic Cell Basics
US Department of Energy
- Solar Photovoltaic Technology Basics
US Department of Energy