For λ < approximately 450 nm, the efficiency enhancement could now be regarded as wholly from the contribution of PL conversion, since the reflectance coefficients at C QD = 0 and 1.6 mg/ml are nearly the same as shown in Figure 3b. Hence, the PL contribution was calculated as the area difference between C QD = 1.6 mg/ml and 0 for λ < approximately 450 nm only, divided by the whole area for C QD = 0. It was 1.04%. Therefore, the rest 5.96% − 1.04% = 4.92% was due to AR. In Figure 5, I-V curves for

bare Si solar cell and Si solar cell coated with QD-doped PLMA (C QD = 0 and 1.6 mg/ml) are depicted. U OC and FF change slightly; only the I SC varies steadily, leading to a change in η. In KU55933 in vitro Table 1, Δη/η 0 for C QD = 3.0 mg/ml is as high as 9.97%, which is the highest efficiency enhancement achieved in this work. However, from Figure 3a, it is certain that the PL contribution to Δη/η 0 at C QD = 3.0 mg/ml is very little. The AR effect

contributes dominantly, which could be attributed to the modification of refractive index gradient [19]. Since many other efficient AR approaches have been developed [19–22], the effect of AR will not be EPZ-6438 further discussed here. Figure 4 EQE curves and emission spectrum of the standard AM0. EQE curves for Si solar cells coated with QD-doped PLMA with C QD = 0 and 1.6 mg/ml (right ordinate) and the power-density-normalized CP-868596 standard AM0 spectrum (left ordinate). The dotted curve is the modified EQE curve for C QD = 0 (right ordinate) under the AM0 condition. Figure 5 I-V curves. For bare Si solar cell and Si solar cells coated with QD-doped PLMA at C QD = 0 and 1.6 mg/ml. Table 1 PV

parameters for Si solar cells after treatments Sample I SC(mA) U OC(V) FF (%) η (%) Δ η /η 0(%) Δ η /η 0(%) (calculated) Bare cell 66.50 0.59 73.65 11.12 – - C QD = 0 74.74 0.59 73.78 12.54 0.00 0.00 C QD = 1.6 mg/ml 78.10 0.59 74.38 Regorafenib 13.24 5.58 5.96 C QD = 3.0 mg/ml 81.08 0.60 74.50 13.79 9.97 – In this work, AM0 solar simulator rather than the more conventional AM1.5 one has been used. This is because the effect of PL conversion on the performance improvement of solar cell is more applicable in the environment with higher UV proportions. The UV proportion in the high altitude or outer space environment, which the AM0 condition mimics, is generally two to three times that in the normal AM1.5 one. On the other hand, from Figure 4, it is seen that the solar cell has high EQE in a broad wavelength range of approximately 450 to 1,000 nm; therefore, although for each wavelength, the corresponding reflectance changes with the changing film thickness due to the light interference, the overall efficiency enhancement is not sensitive to the film thickness, as what we found in our experiments for the film thickness in the range of 100 to 300 nm.