[math-fun] solar cell efficiency record
35.4% energy conversion (sun->electric) efficiency achieved. The light was split into 4 spectral bands each handled with a different semiconductor: Ge: 0.67eV Si: 1.1eV GaInAs: 1.41eV GaInP: 1.88eV I don't understand their splitting scheme. Can it be used with scattered sunlight, i.e. which is not coming from just one direction? In any event, it seems to me this whole approach probably is totally uneconomical because Ge and In are rare. http://newsroom.unsw.edu.au/news/science-tech/milestone-solar-cell-efficienc... (Even greater efficiency has been achieved by the same team but using concentrated sunlight.) -- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)
Germanium is more common than cadmium and indium is about the same as cadmium in the Earth's crust. They are not rare relative to the quantities needed for PV. Using a different semi-conductor to capture photons of different energy wouldn't depend on directionality. The gain in efficiency comes from (a) capturing more photons and (b) capturing a photon with just enough energy to boost the electron into the conduction band with little or no excess. Brent On 5/18/2016 10:34 AM, Warren D Smith wrote:
35.4% energy conversion (sun->electric) efficiency achieved. The light was split into 4 spectral bands each handled with a different semiconductor: Ge: 0.67eV Si: 1.1eV GaInAs: 1.41eV GaInP: 1.88eV I don't understand their splitting scheme. Can it be used with scattered sunlight, i.e. which is not coming from just one direction? In any event, it seems to me this whole approach probably is totally uneconomical because Ge and In are rare. http://newsroom.unsw.edu.au/news/science-tech/milestone-solar-cell-efficienc...
(Even greater efficiency has been achieved by the same team but using concentrated sunlight.)
As semiconductor lithography heads towards 1 nm, a whole new opportunity opens up for solar cells using "quantum dots". Quantum dots in the 2-6 nm size range cover the visible light spectrum. By using feature *size*, rather than feature *composition* through exotic chemicals, quantum dots will enable the efficient capture of light energy in this spectral range w/o using rare chemicals. https://en.wikipedia.org/wiki/Quantum_dot At 06:12 PM 5/18/2016, Brent Meeker wrote:
Germanium is more common than cadmium and indium is about the same as cadmium in the Earth's crust. They are not rare relative to the quantities needed for PV. Using a different semi-conductor to capture photons of different energy wouldn't depend on directionality. The gain in efficiency comes from (a) capturing more photons and (b) capturing a photon with just enough energy to boost the electron into the conduction band with little or no excess.
On 5/18/2016 10:34 AM, Warren D Smith wrote:
In any event, it seems to me this whole approach probably is totally uneconomical because Ge and In are rare.
participants (3)
-
Brent Meeker -
Henry Baker -
Warren D Smith