Consistently high Voc values in p-i-n type perovskite solar cells using Ni3+-doped NiO nanomesh as the hole transporting layer

Leading edge p-i-n type halide perovskite solar cells (PSCs) severely underperform n-i-p PSCs. p-i-n type PSCs that use PEDOT:PSS HTLs struggle to generate open circuit photovoltage (Voc) values higher than 1 V. NiO HTLs have shown greater promise in achieving high Voc values albeit inconsistently. In this report, a NiO nanomesh with Ni3+ defect grown by the hydrothermal method was used to obtain PSCs with Voc values that consistently exceeded 1.10 V (champion Voc = 1.14 V). A champion device photoconversion efficiency (PCE) of 17.75% was observed. Density functional theory (DFT) modeling was used to understand the interfacial properties of the NiO/perovskite interface. The PCE of PSCs constructed using the Ni3+-doped NiO nanomesh HTL was ~34% higher than that of conventional compact NiO based perovskite solar cells. A suite of characterization techniques such as transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), intensity-modulated photocurrent spectroscopy (IMP...