title: Facile synthesis of ultra-small PbSe nanorods for photovoltaic application.
abstract: Nanocrystal array solar cells based on lead chalcogenide quantum dots (QDs) have recently achieved a high power conversion efficiency of over 8%. The device performance is expected to further increase by using 1-dimensional nanorods (NRs), due to their improved carrier transport over zero-dimensional quantum dots. However, previously reported PbSe NRs have not been used in solar cells mainly because of their large diameters, resulting in a small bandgap unsuitable for photovoltaic application. In this work, we have demonstrated a new method for synthesizing monodisperse ultra-small PbSe NRs with the diameter approaching 2 nm (Eg > 1.2 eV), which can be attributed to the use of diphenylphosphine (DPP) and trans-2-octenoic acid (t-2-OA). The introduction of trace DPP can greatly lower the reaction temperature, leading to reduced diameters for the obtained PbSe NRs as well as largely increased yield. The use of short-chain t-2-OA together with oleic acid as capping ligands results in high monomer reactivity, fast nucleus diffusion and high growth rate, which realize the anisotropic growth of ultra-small PbSe NRs at low reaction temperatures. The PbSe NRs show n-type properties and high electron mobility as measured using field-effect transistors. The PbSe NRs with narrow diameters also demonstrate a suitable bandgap for photovoltaic application. They are used for the first time in solar cells and their improved efficiency is demonstrated when used together with QDs.
authors.affiliation: Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, 199 Ren-Ai Road, Suzhou Industrial Park, Suzhou, Jiangsu 215123, P. R. China. wlma@suda.edu.cn.
authors.forename: Lu
authors.initials: L
authors.lastname: Han
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Ningning
authors.initials: N
authors.lastname: Yu
authors.forename: Zeke
authors.initials: Z
authors.lastname: Liu
authors.forename: Jinan
authors.initials: J
authors.lastname: Gu
authors.forename: Jialing
authors.initials: J
authors.lastname: Lu
authors.forename: Wanli
authors.initials: W
authors.lastname: Ma