Tailoring optoelectronic properties of CH3NH3PbI3 perovskite photovoltaics using al nanoparticle modified PC61BM layer

Abstract

In photovoltaics, light harvesting is one of the critical factors for the enhancement of power conversion efficiency (PCE). Photon harvesting can be carried out by various methods in perovskite photovoltaic. The improved light harvesting can also be achieved by trapping the light by incorporating metallic nanoparticles at the interface or in the perovskite active layer itself. Either light is absorbed or scattered by metallic nanoparticles depending on the particle size. When light is absorbed by the nanoparticles (size < 20 nm), it behaves like a sub-wavelength antenna due to localized surface plasmon resonance (LSPR) excitation and hence near field effect of plasmonic particle will be interacting to CH3NH3PbI3 active layer. Larger particles (>20 nm) act as sub-wavelength scattering centers of light and help in trapping incident light. In order to make use of dual effect poly-dispersed spherical aluminium nanoparticles (AlNPs) (size – 20–70 nm) were incorporated in the CH3NH3PbI3 perovskite solar cell at the PC61BM/Al electrode interface. As a result, there is an increase in the optical absorption in the AlNPs embedded device. A detailed study of optical absorption, absorbed light emission characteristics charge trap density and carrier concentration studies, photovoltaic property measurements indicates, improvement in power conversion efficiency arise due to enhancement in JSC. Evaluated device properties indicate that enhancement in JSC arises due to improvement in the active layer photon absorption by both scattering and plasmonic effect in addition to reduced series resistance.