Solar Panel Bandgap

Traditional single junction cells with an optimal band gap for the solar spectrum have a maximum theoretical efficiency of 33 16 the shockley queisser limit.

Solar panel bandgap.

Solar cells with multiple band gap absorber materials improve efficiency by dividing the solar spectrum into smaller bins where the thermodynamic efficiency limit is higher for each bin. Only photons with at least the band gap energy will be able to free electrons to create a current. For solar cells made from silicon to provide pv electricity the photons which hit a solar cell must have energy greater than 1 11 ev. Solar panels produce electricity when sunlight hits their surface and they produce the most energy when that sunlight is exactly perpendicular to the panel face.

Therefore the best angle for your solar panels is the one that allows the panels to get the most direct perpendicular light. This first calculation used the 6000k black body spectrum as an approximation to the solar spectrum. Ideal solar band gaps crystalline silicon the most popular solar cell semiconductor has a bandgap of 1 1 electron volts ev. Put in terms of radiation all the photons in the visible spectrum are strong enough to causeelectrons to jump the band gap.

To knock an electron of a silicon atom at room temperature we must provide a packet of energy greater than 1 11 ev. Reaching this ideal bandgap energy can be difficult but utilizing tunable perovskite solar cells allows for the flexibility to match this value. A simple heterojunction design evolved in which p type cdte was matched with n type cadmium sulfide cds. Solar energy materials solar cells 91 2007 1599 1610 improving solar cell efficiency using photonic band gap materials marian florescua b hwang leea irina puscasuc martin prallec lucia florescua b david z.

Solar panels on a shallow roof capture more sunlight during the summer season whereas solar panels on a steep roof will produce more power during the winter. Solar cells made from cadmium telluride cdte the bandgap energy is 1 44 ev. Dowlinga adepartment of physics and astronomy hearne institute for theoretical physics louisiana state university 202 nicholson hall. Research in cdte dates back to the 1950s because its band gap 1 5 ev is almost a perfect match to the distribution of photons in the solar spectrum in terms of conversion to electricity.

While you can use solar panel trackers to keep them at the optimum angle at all times the costs and complications involved aren t worth it in most cases. Subsequent calculations have used measured global solar spectra am1 5g and included a back surface mirror which increases the maximum efficiency to 33 7 for a solar cell with a bandgap of 1 34 ev.