3.4. Application in two terminal (2T) perovskite/c-Si tandem solar cells
As sketched in Figure 1, we also fabricated SST solar cells with flat front side coated with n-type poly-SiOx and textured rear side coated with p-type poly-SiOx. This solar cell architecture was deployed to form a 2T perovskite/c-Si tandem device with a p-i-n perovskite top device. Due to the textured p-type poly-SiOx CSPC limiting the passivation quality, these solar cells suffered large passivation loss after the ITO deposition. Again, some of the passivation loss was recovered after annealing in hydrogen at 400 °C for 1 hour. The best single junction solar cell achieved a designated area PCE of 16.67% (Voc = 649 mV, Jsc = 34.28 mA/cm2, FF = 74.93%, metallization faction 3.15%, designated area = 3.92 cm2). The current density-voltage characteristic and the EQE spectrum of the single junction solar cell are reported in Figure 7(a) and (b), respectively. From the EQE and reflectance spectra in Figure 7(b), we note large parasitic absorption at short wavelengths (300 - 400 nm) and at very long wavelengths (1000 - 1200 nm). This light is absorbed in the front/rear ITO and in the front/rear poly-SiOx CSPCs. Between 600 and 1000 nm, other than the reflection losses, most of the light is absorbed in c-Si solar cell.