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Cite This: ACS Appl. Energy Mater. 2018, 1, 1834−1839
Inkjet-Printed Triple Cation Perovskite Solar Cells Florian Mathies,*,†,‡ Helge Eggers,∥ Bryce S. Richards,†,§ Gerardo Hernandez-Sosa,†,‡ Uli Lemmer,†,§ and Ulrich W. Paetzold*,†,§ †
Light Technology Institute, Karlsruhe Institute of Technology, Engesserstrasse 13, 76131 Karlsruhe, Germany InnovationLab GmbH, Speyererstrasse 4, 69115 Heidelberg, Germany § Institute of Microstructure Technology, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany ∥ Kirchhoff Institute for Physics, Heidelberg University, Im Neuenheimerfeld 225, 69120 Heidelberg, Germany Downloaded via UNIV OF THE SUNSHINE COAST on June 28, 2018 at 09:00:59 (UTC). See https://pubs.acs.org/sharingguidelines for options on how to legitimately share published articles.
‡
S Supporting Information *
ABSTRACT: Noncontact inkjet printing offers rapid and digital deposition combined with excellent control over the layer formation for printed perovskite solar cells. In this work, inkjet printing is used to deposit triple cation perovskite layers with 10% cesium in a mixed formamidinium/methylammonium lead iodide/bromide composite for solar cells with high temperature and moisture stability. A reliable process control over a wide range of perovskite layer thickness from 175 to 780 nm and corresponding grain sizes is achieved by adjusting the drop spacing of the inkjet printer cartridge. A continuous power output at constant voltage, resulting in a power conversion efficiency of 12.9%, is demonstrated, representing a major improvement from previously reported inkjet-printed methylammonium lead triiodide perovskite solar cells. Moreover, this work highlights the extended resistance of triple cation perovskite solar cells against heat and moisture for our ambient inkjet printing approach. The presented results are a proof of concept for the processability of high efficiency perovskite solar cells using digital inkjet printing for next generation photovoltaic applications. KEYWORDS: inkjet printing, perovskite, solar cell, stability, triple cation, thickness
1. INTRODUCTION
importance for high performance solar cells. Recently, partially inkjet-printed PSCs with efficiencies of up to 16.5% utilizing methylammonium lead iodide have been demonstrated, although this still lags well behind the reported record PCE of 22.1% for PSCs fabricated by spin coating.17−23 To date, research on printed PSCs has been mainly focused on maximizing the PCE. However, a more practical consideration, namely, the long-term stability of the devices, particularly of the perovskite absorber material, is just as important for photovoltaic (PV) applications. Especially methylammonium lead triiodide, the most prominent organometal halide perovskite absorber material for PV, strongly suffers from degradation upon contact with moisture, as well as thermal instability.24,25 Impressive results leading to both increased PCE and thermal stability have been presented, realized via mixing different cations following the Goldschmidt tolerance factor of ionic radii.26 In this regard, the most promising attempt based on a combination of methylammonium and formamidinium to form a mixed halide perovskite has
In recent years, the enormous potential of noncontact digital 7 printing techniques for low cost, high throughput, and large area fabrication of a large variety of optoelectronic devices has been demonstrated. The high level of customization and compatibility with a broad range of substrates makes digital printing a promising process for a vast variety of applications such as integrated circuits, lab-on-a-chip systems, light emitting devices, and solar cells.1−6 Already to date, industrial inkjet printers, compatible with high throughput roll-to-roll or sheetto-sheet processes, have been installed in organic light emitting device manufacturing sites.7 Regarding the printability of organometal halide perovskite solar cells (PSCs), most of the research has been focused on high throughput techniques such as spray coating, blade coating, slot die, and roll-to-roll processes.8−14 Power conversion efficiencies (PCEs) of up to 15.7% have already been demonstrated for partially slot die coated devices.15 Digital inkjet printing has so far mainly been investigated for the purpose of fabricating PSCs of arbitrary shape and area.16 Beyond the freedom of design, inkjet printing of perovskites affords very good control over the crystallization behavior of organometal halide perovskite layers, which is of crucial © 2018 American Chemical Society
Received: February 15, 2018 Accepted: April 18, 2018 Published: April 18, 2018 1834
DOI: 10.1021/acsaem.8b00222 ACS Appl. Energy Mater. 2018, 1, 1834−1839
Letter
ACS Applied Energy Materials been reported in literature.27,28 Furthermore, an increase of PCE and stability has been demonstrated for triple cation perovskites, where a small amount of cesium (
