“Miracle” tandem solar cells

The production of tandem solar cells combining silicon with perovskite – a semi-conducting crystal that absorbs sunlight – follows years of academic research with the mineral, hailed as a “miracle material”

Solar cell efficiency (Sun's energy converted into electricity, percent)

Crystalline silicon cell
Perovskite solar cell


30 25 20 15 10
77 80 85 90 95 2000 05 10 15 20

1977: 13.9%
1982: 16.7%
1987: 22.1%
1994: 24.2%
1999: 25.0%
2012: 25.5%
2017: 26.7%
2022: 26.8%

2012: 10.9%
2017: 23.0%
2022: 32.5%

Perovskite-silicon solar cell Gold contacts

Cathode: Gold and layer of spiro-OMeTAD

Perovskite 

Silicon layer

Anode: Fluorine-doped tin oxide (FTO) and titanium dioxide (TiO2 ) – semiconductor that conducts electrons

Glass substrate

Sunlight: Composed of visible, infrared and ultraviolet light
                
Perovskite: Outperforms crystalline silicon in absorbing short wave ultraviolet – high energy part of spectrum
 
IF 
UV  

Sources: Bloomberg, Reuters, Scientific American
Picture: Getty Images
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