Optoelectronic excitations and photovoltaic effect in strongly correlated materials

Abstract

Solar cells based on conventional semiconductors have low efficiency in converting solar energy into electricity because the excess energy beyond the gap of an incident solar photon is converted into heat by phonons. Here we show by ab initio methods that the presence of strong Coulomb interactions in strongly correlated insulators (SCI) causes the highly photo-excited electron-hole pair to decay fast into multiple electron-hole pairs via impact ionization (II). We show that the II rate in the insulating $M_1$ phase of vanadium dioxide (chosen for this study as it is considered a prototypical SCI) is two orders of magnitude higher than in Si and much higher than the rate of hot electron/hole decay due to phonons. Our results indicate that a rather broad class of materials may be harnessed for an efficient solar-to-electrical energy conversion that has been not considered before.

5 Latex pages, 3 figures, and also supplementary material

References in corpus (6)

• Electrodynamics of the vanadium oxides VO2 and V2O3
• Predictive GW calculations using plane waves and pseudopotentials
• Optical properties of correlated materials -- Generalized Peierls approach and its application to VO2
• GW method applied to localized 4f electron systems
• Role of electron-electron and electron-phonon interaction effect in the optical conductivity of VO2
• Many-body Electronic Structure of Metallic alpha-Uranium

Cited by in corpus (5)

• Convergence of quasiparticle self-consistent GW calculations of transition metal monoxides
• Many-body recombination in insulating cuprates
• Multiple exciton generation in VO2
• Growth and Characterization of Off-Stoichiometric LaVO${}_3$ Thin Films
• Excitonic-trion population in two-dimensional halide perovskites