To convert from responsivity (R λ, in A/W) to QE λ (on a scale 0 to 1): Q E λ λ = R λ λ λ λ × × h c e ≈ ≈ R λ λ λ λ × × ( 1240 W ⋅ ⋅ n m / A ) where λ is the wavelength in nm, h is the Planck constant, c is the speed of light in vacuum, and e is the elementary charge. Note that the unit W/A (watts per ampere) is equivalent to V (volts).