title: Correlated electron-hole plasma in organometal perovskites.
abstract: Organic-inorganic perovskites are a class of solution-processed semiconductors holding promise for the realization of low-cost efficient solar cells and on-chip lasers. Despite the recent attention they have attracted, fundamental aspects of the photophysics underlying device operation still remain elusive. Here we use photoluminescence and transmission spectroscopy to show that photoexcitations give rise to a conducting plasma of unbound but Coulomb-correlated electron-hole pairs at all excitations of interest for light-energy conversion and stimulated optical amplification. The conductive nature of the photoexcited plasma has crucial consequences for perovskite-based devices: in solar cells, it ensures efficient charge separation and ambipolar transport while, concerning lasing, it provides a low threshold for light amplification and justifies a favourable outlook for the demonstration of an electrically driven laser. We find a significant trap density, whose cross-section for carrier capture is however low, yielding a minor impact on device performance.
authors.affiliation: Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Saba
authors.affiliation: Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Cadelano
authors.affiliation: Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Marongiu
authors.affiliation: Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
authors.forename: Feipeng
authors.initials: F
authors.lastname: Chen
authors.affiliation: Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
authors.forename: Valerio
authors.initials: V
authors.lastname: Sarritzu
authors.affiliation: Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
authors.forename: Nicola
authors.initials: N
authors.lastname: Sestu
authors.affiliation: Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Figus
authors.affiliation: Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
authors.forename: Mauro
authors.initials: M
authors.lastname: Aresti
authors.affiliation: Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Piras
authors.affiliation: Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
authors.forename: Alessandra Geddo
authors.initials: AG
authors.lastname: Lehmann
authors.affiliation: Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Cannas
authors.affiliation: Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
authors.forename: Anna
authors.initials: A
authors.lastname: Musinu
authors.affiliation: Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Quochi
authors.affiliation: Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Mura
authors.affiliation: Dipartimento di Fisica, Università degli Studi di Cagliari, I-09042 Monserrato, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Bongiovanni