Abstract

Carrier multiplication (CM), the process of generating multiple charge carriers from a single photon, offers an opportunity to exceed the Shockley-Queisser limit in photovoltaic applications. Despite extensive research, no material has yet achieved ideal CM efficiency, primarily owing to significant energy losses from carrier-lattice scattering. In this study, monolayer MoSe₂ is shown to attain the theoretical maximum CM efficiency permitted by energy-momentum conservation using ultrafast transient absorption spectroscopy. First-principles calculations are used to identify abundant CM pathways enabled by 2Eg band nesting, while femtosecond spatiotemporal spectroscopy reveals exceptional hot-carrier diffusion in the monolayer relative to bulk MoSe2.

Abstract

Carrier multiplication (CM), the process of generating multiple charge carriers from a single photon, offers an opportunity to exceed the Shockley-Queisser limit in photovoltaic applications. Despite extensive research, no material has yet achieved ideal CM efficiency, primarily owing to significant energy losses from carrier-lattice scattering. In this study, monolayer MoSe₂ is shown to attain the theoretical maximum CM efficiency permitted by energy-momentum conservation using ultrafast transient absorption spectroscopy. First-principles calculations are used to identify abundant CM pathways enabled by 2Eg band nesting, while femtosecond spatiotemporal spectroscopy reveals exceptional hot-carrier diffusion in the monolayer relative to bulk MoSe2.

Abstract

Carrier multiplication (CM), the process of generating multiple charge carriers from a single photon, offers an opportunity to exceed the Shockley-Queisser limit in photovoltaic applications. Despite extensive research, no material has yet achieved ideal CM efficiency, primarily owing to significant energy losses from carrier-lattice scattering. In this study, monolayer MoSe₂ is shown to attain the theoretical maximum CM efficiency permitted by energy-momentum conservation using ultrafast transient absorption spectroscopy. First-principles calculations are used to identify abundant CM pathways enabled by 2Eg band nesting, while femtosecond spatiotemporal spectroscopy reveals exceptional hot-carrier diffusion in the monolayer relative to bulk MoSe2.

Abstract

Carrier multiplication (CM), the process of generating multiple charge carriers from a single photon, offers an opportunity to exceed the Shockley-Queisser limit in photovoltaic applications. Despite extensive research, no material has yet achieved ideal CM efficiency, primarily owing to significant energy losses from carrier-lattice scattering. In this study, monolayer MoSe₂ is shown to attain the theoretical maximum CM efficiency permitted by energy-momentum conservation using ultrafast transient absorption spectroscopy. First-principles calculations are used to identify abundant CM pathways enabled by 2Eg band nesting, while femtosecond spatiotemporal spectroscopy reveals exceptional hot-carrier diffusion in the monolayer relative to bulk MoSe2.