Performance enhancement of graphene/porous Si solar cells by employing layer-controlled MoS2

Porous Si (PSi) is attractive due to its high light absorption originating from the large surface to volume ratio and additional benefits such as surface passivation and texturization effects, thereby possibly improving Si-based solar cells. Here, we first employ (trifluoromethanesulfonyl)-amide (TFSA)-doped graphene (TFSA-GR) transparent conducive electrode and MoS(2 )interlayer in GR/PSi solar cells. The photovoltaic parameters of the cell strongly depend on the doping concentration (n(D)) of the TFSA- GR and the number of layers (L-n) of the MoS2. In particular, the MoS2 interlayer well adjusts the band alignment between the TFSA-GR and PSi, thereby facilitating the separation/collection of carriers, resulting in the enhancement of the photovoltaic parameters. TiOx passivation is also used for reducing the recombination loss at the back surface. The TFSA-GR/MoS2/PSi/Si/TiOx solar cells show maximum power conversion efficiency (PCE) of 13.18% at n D = 20 mM and L-n = 4. While the PCE is monitored under 20-22 degrees C and 40% humidity for 30 days, it shows only a 15% loss, excellent long-term stability.