Electron trapping action of functionalized carbon nanotubes and PEDOT: PSS nanocomposite in inverted perovskite solar cell

Organic –inorganic metal halide perovskite light sensitizer is a fast-growing field in photovoltaic which reached a maximum certified efficiency of 22.1%. Contact layer engineering is widely focused areas in the field of perovskite solar cell to increase power conversion efficiency and stability of the cell. PEDOT: PSS is a reliable organic hole transporting material showing intact performance for inverted perovskite solar cell. A nanocomposite of Functionalised multiwalled carbon nanotubes (f-MWCTs) and PEDOT: PSS are functioned as hole transporter. f-MWCTs are taken in two different volume percentages such as 10% volume of PEDOT: PSS, 20% volume of PEDOT: PSS are added to 250µL of PEDOT: PSS to prepare the composite. Transmittance and surface morphology of PEDOT: PSS-f-MWCTs nanocomposite film is analysed. UV-Visible spectrum of MAPbI₃ thin film shows an energy gap in between 1.5-1.6eV. In PL-spectrum of MAPbI₃ an intense peak is at 428nm. XRD analysis confirms hexagonal phase of MAPbI₃. An inverted perovskite solar cell with architecture FTO glass substrate/ PEDOT: PSS-F-MWCTs nanocomposite/ MAPbI3/ TiO₂ compact layer/ FTO glass substrate is fabricated and current voltage characterisations are taken. XRD and SEM analysis of TiO₂ film is taken. All the synthesis process and fabrication of the cell is carried out at ambient atmospheric conditions. Addition of 20V% of f-MWCTs increase the fill factor to 31% from 21%. MWCTs increase the number of minority carriers in PEDOT: PSS hole conductor. These minority carriers recombine with the positive vacancy formed in the perovskite light absorber. Hence only a smaller number of holes can transfer through PEDOT: PSS. This leads to lowering the value of I_sc and retards the performance of the cell.