Hybrid solar cells with β- and γ- gallium oxide nanoparticles

Herein, hybrid composite layers made of nanocrystalline β-Ga₂O₃ or γ-Ga₂O₃ within poly(3,4-ethylenedioxythiophene):-polystyrene (PEDOT:PSS) have been studied in order to be incorporated into hybrid solar cells. Structural, morphological, optical and electrical characterization has been carried out with X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), PL excitation (PLE), cathodoluminescence (CL) and Raman spectroscopy. Bandgaps of 4.7 and 4.9 eV for γ- and β- phases, respectively, are obtained from PLE. Beside broad luminescence bands on 2.7–2.9 eV for the two phases, a band on 4.7 eV is obtained only for γ-Ga₂O₃, coincident with the observed PLE band. Minority carrier lifetimes are higher when γ-Ga₂O₃ nanoparticles are used for the hybrid system.