title: Heterovalent cation substitutional doping for quantum dot homojunction solar cells.
abstract: Colloidal quantum dots have emerged as a material platform for low-cost high-performance optoelectronics. At the heart of optoelectronic devices lies the formation of a junction, which requires the intimate contact of n-type and p-type semiconductors. Doping in bulk semiconductors has been largely deployed for many decades, yet electronically active doping in quantum dots has remained a challenge and the demonstration of robust functional optoelectronic devices had thus far been elusive. Here we report an optoelectronic device, a quantum dot homojunction solar cell, based on heterovalent cation substitution. We used PbS quantum dots as a reference material, which is a p-type semiconductor, and we employed Bi-doping to transform it into an n-type semiconductor. We then combined the two layers into a homojunction device operating as a solar cell robustly under ambient air conditions with power conversion efficiency of 2.7%.
authors.affiliation: ICFO-Institut de Ciències Fotòniques, Avenue Carl Friedrich Gauss 3, 08860 Castelldefels, Barcelona, Spain.
authors.forename: Alexandros
authors.initials: A
authors.lastname: Stavrinadis
authors.affiliation: ICFO-Institut de Ciències Fotòniques, Avenue Carl Friedrich Gauss 3, 08860 Castelldefels, Barcelona, Spain.
authors.forename: Arup K
authors.initials: AK
authors.lastname: Rath
authors.affiliation: ICFO-Institut de Ciències Fotòniques, Avenue Carl Friedrich Gauss 3, 08860 Castelldefels, Barcelona, Spain.
authors.forename: F Pelayo García
authors.initials: FP
authors.lastname: de Arquer
authors.affiliation: ICFO-Institut de Ciències Fotòniques, Avenue Carl Friedrich Gauss 3, 08860 Castelldefels, Barcelona, Spain.
authors.forename: Silke L
authors.initials: SL
authors.lastname: Diedenhofen
authors.affiliation: Laboratorio de Microscopías Avanzadas (LMA), Instituto de Nanociencia de Aragon (INA) - ARAID and Departamento de Fisica de la Materia Condensada, Universidad de Zaragoza, 50018 Zaragoza, Spain.
authors.forename: César
authors.initials: C
authors.lastname: Magén
authors.affiliation: ICFO-Institut de Ciències Fotòniques, Avenue Carl Friedrich Gauss 3, 08860 Castelldefels, Barcelona, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Martinez
authors.affiliation: ICFO-Institut de Ciències Fotòniques, Avenue Carl Friedrich Gauss 3, 08860 Castelldefels, Barcelona, Spain.
authors.forename: David
authors.initials: D
authors.lastname: So
authors.affiliation: ICFO-Institut de Ciències Fotòniques, Avenue Carl Friedrich Gauss 3, 08860 Castelldefels, Barcelona, Spain.
authors.forename: Gerasimos
authors.initials: G
authors.lastname: Konstantatos