Chemical vapor deposited polymer layer for efficient passivation of planar perovskite solar cells. Issue 38 (28th September 2020)

• Record Type: Journal Article
• Authors: Malekshahi Byranvand, Mahdi; Behboodi-Sadabad, Farid; Alrhman Eliwi, Abed; Trouillet, Vanessa; Welle, Alexander; Ternes, Simon; Hossain, Ihteaz Muhaimeen; Khan, Motiur Rahman; Schwenzer, Jonas Alexander; Farooq, Amjad; Richards, Bryce Sydney; Lahann, Joerg; Paetzold, Ulrich Wilhelm
• Is Part Of: Journal of materials chemistry. Volume 8:Issue 38(2020)
• Page Start: 20122
• Page End: 20132
• Publication Date: 2020-09-28
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/d0ta06646j
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Controlling the thickness and homogeneity of thin passivation layers on polycrystalline perovskite thin films is challenging. We report CVD polymerization of poly( p -xylylene) layers at controlled substrate temperatures for efficient surface passivation of perovskite films. Abstract : Reducing non-radiative recombination losses by advanced passivation strategies is pivotal to maximize the power conversion efficiency (PCE) of perovskite solar cells (PSCs). Previously, polymers such as poly(methyl methacrylate), poly(ethylene oxide), and polystyrene were successfully applied in solution-processed passivation layers. However, controlling the thickness and homogeneity of these ultra-thin passivation layers on top of polycrystalline perovskite thin films is a major challenge. In response to this challenge, this work reports on chemical vapor deposition (CVD) polymerization of poly( p -xylylene) (PPX) layers at controlled substrate temperatures (14–16 °C) for efficient surface passivation of perovskite thin films. Prototype double-cation PSCs using a ∼1 nm PPX passivation layer exhibit an increase in open-circuit voltage ( V OC ) of ∼40 mV along with an enhanced fill factor (FF) compared to a non-passivated PSC. These improvements result in a substantially enhanced PCE of 20.4% compared to 19.4% for the non-passivated PSC. Moreover, the power output measurements over 30 days under ambient atmosphere (relative humidity ∼40–50%) confirm that the passivated PSCs are more resilient towards humidity-induced degradation. Considering the urge to develop reliable, scalable and homogeneous deposition techniques for future large-area perovskite solar modules, this work establishes CVD polymerization as a novel approach for the passivation of perovskite thin films.