Nitrogen-doped titanium dioxide as a novel eco-friendly hole transport layer in lead-free CsSnI3 based perovskite solar cells.

• A high- efficiency, stable, and printable CeO 2 /FaSnI 3 /Spiro-OMeTAD perovskite solar cell is proposed. • Effect of different parameters such as thickness, defect density, and donor density on photovoltaic characteristic parameters is investigated. • Effect of conventional TiO 2 substitution with CeO 2 on efficiency improvement of devices is discussed. • Role of capture cross section of electrons, and holes is explained. After an abrupt rise in the efficiency of perovskite solar cells (PSCs), hole transport layer (HTL) as an essential factor for fabricating efficient PSC devices attract attentions. The pristine spiro-OMeTADspiro-OMeTAD, as most widely used HTL, still suffers from poor electrical conductivity, low hole mobility, and low oxidation rate. In this research, the spiro-OMeTAD is replaced by nitrogen doped TiO 2 (N-TiO 2) HTL. Then, the variation in the device design key parameters such as the thickness and bulk defect density of perovskite layer, simultaneous modifications of defect density and defect energy level, and acceptor doping concentration in absorber layer, and operating temperature are examined with their impact on the photovoltaic characteristic parameters. The standard lead-free CsSnI 3 –based PSCs with spiro-OMeTAD HTL is simulated using SCAPS-1D software. The CsSnI 3 -based solar cell with N-TiO 2 as HTL showed higher efficiency of 27.03 % than the standard device with PCE of 23.63 % for conventional spiro-OMeTAD HTL. [Display omitted] [ABSTRACT FROM AUTHOR]