doping level

Nb (cm−3)

Conversion efficiency (%)

under moderate concentration (C = 50 Suns)

Conversion efficiency (%) under normal illumination (C = 1 Sun)

1013

30.79

18.76

5 × 1013

26.62

16.02

1014

24.67

14.74

5 × 1014

19.80

11.54

1015

17.57

10.09

5 × 1015

12.18

6.69

1016

9.87

5.31

Variation rate (%)

67.94

71.70