title: Efficiency enhancement of perovskite solar cells through fast electron extraction: the role of graphene quantum dots.
abstract: We report on a significant power conversion efficiency improvement of perovskite solar cells from 8.81% to 10.15% due to insertion of an ultrathin graphene quantum dots (GQDs) layer between perovskite and TiO2. A strong quenching of perovskite photoluminescence was observed at ∼760 nm upon the addition of the GQDs, which is pronouncedly correlated with the increase of the IPCE and the APCE of the respective cells. From the transient absorption measurements, the improved cell efficiency can be attributed to the much faster electron extraction with the presence of GQDs (90-106 ps) than without their presence (260-307 ps). This work highlights that GQDs can act as a superfast electron tunnel for optoelectronic devices.
authors.affiliation: Nano Science and Technology Program and ‡Department of Chemistry, The Hong Kong University of Science and Technology , Clear Water Bay, Kowloon, Hong Kong.
authors.forename: Zonglong
authors.initials: Z
authors.lastname: Zhu
authors.forename: Jiani
authors.initials: J
authors.lastname: Ma
authors.forename: Zilong
authors.initials: Z
authors.lastname: Wang
authors.forename: Cheng
authors.initials: C
authors.lastname: Mu
authors.forename: Zetan
authors.initials: Z
authors.lastname: Fan
authors.forename: Lili
authors.initials: L
authors.lastname: Du
authors.forename: Yang
authors.initials: Y
authors.lastname: Bai
authors.forename: Louzhen
authors.initials: L
authors.lastname: Fan
authors.forename: He
authors.initials: H
authors.lastname: Yan
authors.forename: David Lee
authors.initials: DL
authors.lastname: Phillips
authors.forename: Shihe
authors.initials: S
authors.lastname: Yang