Fig. 1: Surface passivation of perovskite absorber with phosphonic acids.
From: 60 cm2 perovskite-silicon tandem solar cells with an efficiency of 28.9% by homogeneous passivation
A Structural formulas of methylphosphonic acid (MPA), benzylphosphonic acid (BPA), fluorobenzylphosphonic acid (FBPA), and pentaflourobenzylphosphonic acid (pFBPA). B Non-radiative losses of half-cells with different surface treatments. C XPS Pb 4f spectra of layers with different surface treatments. D Side view of perovskite⋯C60 interface with substitution of IPb-I by IPb-OPO2HCH2C6F5. E Energy of substitution of IPb-I by IPb-OPO2HCH2R (Es, eV) for partial surface substitution (12.5%). F Surface photovoltage amplitude extracted from Kelvin probe measurements for ITO/HTL/perovskite/PA/perovskite samples. G Open-circuit voltage of single junction devices (1.65 eV) with different surface treatments. H Slab dipole (D, De) for the perovskite surface with partial surface substitution (12.5%) of MPA, BPA, FBPA, and pFBPA.
