title: High efficiency air-processed dithienogermole-based polymer solar cells.
abstract: The effect of air processing, with air exposure varying from minutes to hours prior to encapsulation, on photovoltaic device performance has been studied through a series of electrical characterizations and optical simulations for a donor/acceptor polymer-based organic solar cell based on poly(dithienogermole-alt-thienopyrrolodione) p(DTG-TPD)/PC71BM blends. A ∼10% degradation in power conversion efficiency was observed due to air processing with 10 min exposure time, with AM1.5 power conversion efficiencies (PCEs) decreasing from 8.5 ± 0.25% for devices processed in inert nitrogen atmosphere to 7.7 ± 0.18% for devices processed in ambient air. After 3 h air exposure, the PCE leveled off at 7.04 ± 0.1%. This decrease is attributed partially to interface issues caused by exposure of the electrode materials to oxygen and water and partially to a degradation of the hole transport in the active layer.
authors: Department of Materials Science and Engineering, University of Florida , Gainesville, Florida 32611, United States.
authors: Iordania
authors: I
authors: Constantinou
authors: Tzung-Han
authors: TH
authors: Lai
authors: Dewei
authors: D
authors: Zhao
authors: Erik D
authors: ED
authors: Klump
authors: James J
authors: JJ
authors: Deininger
authors: Chi Kin
authors: CK
authors: Lo
authors: John R
authors: JR
authors: Reynolds
authors: Franky
authors: F
authors: So
keywords: air processing; charge mobility; conjugated polymers; dithienogermole; fullerenes; organic photovoltaics; solar cells