Effect of interfacial passivation on inverted pyramid silicon/poly(3,4-ethylenedioxythiophene):Poly(styrenesulfonate) heterojunction solar cells

Abstract

The poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and inverted pyramid n-silicon heterojunction solar cells have been extensively investigated based on their light trapping behaviour, rationally high efficiency and cost effectiveness. However, inferior junction conformity still remains a great challenge. In this work, we present the effect of passivation using aluminium oxide (Al2O3) on the front surface and titanium oxide (TiO2) on rear interface in the inverted pyramid -Si/PEDOT: PSS heterojunction solar cells using the atomic layer deposition technique. The front surface Al2O3 layer can enhance the surface energy, which generates the uniform coating of PEDOT:PSS, acting as an electron blocking layer. Furthermore, TiO2 thin layer deposited on rear interface works as a hole blocking layer, which can suppress the electrical losses and the charge recombination. The best cell demonstrated a conversion efficiency of 16.04% with an open-circuit voltage of 0.63 V, fill factor of 71.5% and a high current density of 35.45 mA/cm2. These findings suggest a promising approach to attainment of next-generation hybrid solar cells.