High-Performance Flexible Perovskite Solar Cells on Ultrathin Glass: Implications of the TCO

Abstract

For halide perovskite solar cells (PSCs) to fulfill their vast potential for combining low-cost, high efficiency, and high throughput production they must be scaled using a truly transformative method, such as roll-to-roll processing. Bringing this reality closer to fruition, the present work demonstrates flexible perovskite solar cells with 18.1% power conversion efficiency on flexible Willow Glass substrates. We highlight the importance of the transparent conductive oxide (TCO) layers on device performance by studying various TCOs. While tin-doped indium oxide (ITO) and indium zinc oxide (IZO) based PSC devices demonstrate high photovoltaic performances, aluminum-doped zinc oxide (AZO) based devices underperformed in all device parameters. Analysis of X-ray photoemission spectroscopy data shows that the stoichiometry of the perovskite film surface changes dramatically when it is fabricated on AZO, demonstrating the importance of the substrate in perovskite film formation.

Recent Advances of Device Components toward Efficient Flexible Perovskite Solar Cells

“…AZO: aluminum‐doped zinc oxide; ITO: tin‐doped indium oxide; IZO: indium zinc oxide. Reproduced with permission . Copyright 2017, American Chemical Society.…”

“…Impressive progress has also been made with other diverse flexible substrates, such as CNT fiber, ultrathin flexible glass, muscovite mica, and nanopaper, among which, FPSCs based on ultrathin flexible willow glass shows the highest PCE over 18% . The ultrathin willow glass possesses high‐temperature tolerance up to 500 °C, together with a low thermal expansion coefficient of 2.5 × 10 −6 K −1 , which holds merits of being a substrate for the high‐temperature fabrication of FPSCs.…”

“…With indium zinc oxide (IZO) being the transparent conductive layer, the final device obtained a PCE as high as 18.1% (see Figure e). However, the ultrathin willow glass is of moderate mechanical flexibility, thus cannot meet the requirement for applications of highly flexible devices …”

SnO2‐Based Perovskite Solar Cells: Configuration Design and Performance Improvement

“…e) Structure diagram of flexible PSCs with a configuration of willow glass/TCO/(SnO 2 ETL)/CsMAFA/Spiro‐OMeTAD/MoO x /Au (TCO refers to transparent conductive oxide, such as ITO, IZO, or AZO). Reproduced with permission . Copyright 2017, American Chemical Society.…”

“…Willow glass has been used as the substrate material of flexible PSCs by Tavakoli et al Dou et al used willow glass as the flexible substrate and SnO 2 nanoparticles reported in ref. as the ETL material . They used different TCOs as the anode electrode of flexible solar cells, as shown in Figure e.…”