Electrode Transport Layer–Metal Electrode Interface Morphology Tailoring for Enhancing the Performance of Perovskite Solar Cells
Bidisha Nath, Praveen C. Ramamurthy, D. Roy Mahapatra, Gopalkrishna Hegde
Abstract
In the field of photovoltaics, methylammonium lead iodide (MAPbI3) is the most emerging light absorber material because of its excellent optoelectronic properties. Perovskite solar cells with P–I–N device architecture were fabricated with thermally evaporated metal electrodes from different sources like silver nanoparticles and bulk silver shots. Film topography, surface morphology, structure, and grain size were observed using various characterization techniques. Top electrodes with better roughness matching with the transport layer were obtained by thermal evaporation of metal nanopowder. Various electrical characterization techniques, including current density (J) vs voltage (V) and capacitance measurements, were carried out under light and dark conditions for investigating the device performance. Devices with electrodes thermally evaporated using nanopowder showed enhancement in device performance with a lower series resistance and a higher shunt resistance, as observed from J–V characteristics. An open-circuit voltage improvement of ∼14% and a power conversion efficiency enhancement of ∼13% have been observed. A considerable improvement in contact resistances has also been noted. The idea about the recombination of devices can be obtained from J–V measurements with varying illumination intensities. The higher carrier concentration in the device based on a Ag NP electrode can be related to the contribution of the less recombination because of the reduced number of traps. These findings support the purpose of using metal nanopowder instead of the bulk form of metals for thermally evaporated top electrodes in perovskite solar cells.