Table 1.

Theoretical limiting efficiency for common solar cell absorbers when powering ideal water splitting

Material	Eg/eV	ηSF × 100%
c-Si*	1.12	26.9
Cu(In1–x,Gax)Se2	1.15†	26.1
GaAs	1.42	19.7
CdTe	1.44	19.2
a-Si‡	1.7	26.8

*Crystalline silicon.

^†Band gap is representative of high-efficiency Cu(In_1–x,Ga_x)Se₂ devices (32).

^‡Amorphous silicon.