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.