Perovskite Solar Cells on Polymer‐Coated Smooth and Rough Steel Substrates

Abstract

Building integration of perovskite solar cells could 1 day become feasible because of their low cost, aesthetics, lightweight, and impressive power conversion efficiency (PCE). [1][2][3][4][5] When focusing on potential substrate materials compatible with the building industry, coated steel offers an interesting perspective because it is one of the most common architectural materials, especially in industrial buildings. Steel is a cheap (substrate) material and offers excellent mechanical, heat resistance, and barrier properties against oxygen and humidity. [6,7] Combining perovskite solar cells with steel can give added value to this commonly employed building material. One of the challenges to tackle when fabricating solar cells directly on steel substrates is the higher surface roughness as compared to glass or polymer film which can be fatal for thin-film solar cells. Using smooth steel substrates would add to the cost due to the extra surface polishing steps. The cost can be reduced when combining rough steel substrates with an additional planarization layer. [8] Fabricating perovskite solar cells on rough substrates may reduce device performance and yield, due to irregularities such as spike-like protrusions, valleys, and peaks. To investigate the impact of surface roughness on the photovoltaic performance, we developed a substrate-configuration n-i-p solar cell for coated steel substrates (Figure 1). Fabrication of perovskite solar cells on rough substrates has been mostly studied in superstrateconfiguration single-junction and top-illuminated perovskite Si monolithic tandem solar cells. [9][10][11][12][13][14][15] In several studies on tandem solar cell applications a rough pyramidal-textured Si substrate has been used. To achieve a conformal coverage of the perovskite active layer, the perovskite layer needs to be sufficiently thick, or it needs to be deposited via co-evaporation [9][10][11] or a hybrid evaporation/spin coating deposition method. [12][13][14] Tockhorn et al. demonstrated conformal coating of the perovskite active layer in single-junction superstrate-configuration perovskite solar cells by employing a self-assembled [2-(9H-carbazol-9-yl)ethyl]phosphonic acid (2PACz) monolayer hole transport layer (HTL) on a nanotextured indium tin oxide (ITO) glass substrate providing 19.7% efficiency. [15] In substrate-configuration perovskite solar cells, most devices have been fabricated on polished Ti foils, reaching efficiencies up to 15%. [16] Although most studies on substrate-configuration perovskite solar cells use polished Ti

p–i–n Perovskite Solar Cells on Steel Substrates

“… 3 Achieving high power conversion efficiencies (PCEs) has been challenging for substrate-configuration PSCs deposited on metal substrates. 4 − 20 Substrate-configurations have also been designed for perovskite photovoltaic metal fibers. 21 − 23 The highest reported efficiencies for PSCs on metal substrates range from 14.7 to 15.2% for substrate-configuration PSCs on metal substrates 12 , 13 , 19 and are less than for superstrate-configuration architectures, where the PSC is built on and illuminated through a transparent glass substrate.…”

“…Herein, we demonstrate an efficient substrate-configuration p–i–n PSC on steel coated with a polyamide-imide (PAI) planarization layer. We chose to use a Ni-plated steel substrate because it is relatively smooth and presents moderate macroscopic roughness 20 and excellent chemical resistance. Ni-plated steel substrates are commonly used in batteries.…”

“…When PSCs are fabricated on a metal foil or rigid substrate, a so-called substrate configuration is required in which the cell is illuminated via a transparent top electrode, similar to semi-transparent solar cells . Achieving high power conversion efficiencies (PCEs) has been challenging for substrate-configuration PSCs deposited on metal substrates. − Substrate-configurations have also been designed for perovskite photovoltaic metal fibers. − The highest reported efficiencies for PSCs on metal substrates range from 14.7 to 15.2% for substrate-configuration PSCs on metal substrates ,, and are less than for superstrate-configuration architectures, where the PSC is built on and illuminated through a transparent glass substrate. Superstrate-configuration PSCs recently reached a record PCE of 25.7% .…”

“…31 Herein, we demonstrate an efficient substrate-configuration p−i−n PSC on steel coated with a polyamide-imide (PAI) planarization layer. We chose to use a Ni-plated steel substrate because it is relatively smooth and presents moderate macroscopic roughness 20 The planarization layer serves as an insulating layer. An opaque titanium electrode covered with a thin sputtered ITO layer to enable binding of the phosphonic acid anchoring groups of the 2PACz monolayer serves as a hole-collecting electrode.…”

Textured Stainless Steel as a Platform for Black Mg2Si/Si Heterojunction Solar Cells with Advanced Photovoltaic Performance

“…Nevertheless, the feasibility of using an SS substrate was demonstrated for Si, amorphous Si (a-Si), copper indium gallium selenide (CIGS), and perovskite solar cells [ 21 , 22 , 23 , 24 ]. However, such solutions suffer from either the formation of iron- and chrome-related deep-level “killers” or metal silicide precipitation, which accompanies growth of the absorbing layers atop SS due to the intense diffusion of contaminants from SS.…”