An improvement on the conversion efficiency of Si/CZTS solar cells by LSPR effect of embedded plasmonic Au nanoparticles

In this work, Au/Si/CZTS/Ag and Au/Si/plasmonic-CZTS/Ag solar cells have been produced using PLD technique. These CZTS solar cells have been produced based on p-type CZTS ultrathin films at different thicknesses of 61 nm, 112 nm and 210 nm which were grown on an n-type Si wafer. Morphologic and crystalline structures as well as optical characteristics of CZTS ultrathin films have been investigated by courtesy of AFM, XRD and UV-vis spectra. J-V characteristics of CZTS solar cells have been obtained under AM 1.5 solar radiation of 80 mW/cm(2). It has been observed that J(sc), V-oc and eta values of CZTS solar cells increase as thickness of CZTS ultrathin films are diagnosed to an optimum thickness. But, CZTS ultrathin films at thickness of 61 nm and 112 nm have low absorption rate and it was observed that absorption rate of CZTS ultrathin films increase dramatically in visible and NIR regions after Au plasmonic nanoparticles were embedded in these CZTS ultrathin films. Furthermore, J(sc) and eta values of plasmonic CZTS solar cells increase and that increase can be attributed to the transfer of electrons from the plasmonic Au NPs to the conduction band of CZTS semiconductor, the photon absorption of CZTS ultrathin films from visible to NIR region in the wide spectral region, and the increase in the path length of light through in CZTS semiconductor by photon scattering of Au nanoparticles.