Metal-Free Interconnecting Layer for Monolithic Perovskite/Organic Tandem Solar Cells with Enhanced Outdoor Stability

Abstract

Photovoltaics with monolithically connected tandem architectures have the potential to achieve high efficiencies owing to enhanced spectral absorption and reduced thermal losses. To achieve this, photoactive layers with complementary absorption and interconnecting layers, which are robust, transparent, and energetically suitable, are essential. Here, we investigate a strategy to create an efficient, highly transparent, ohmic, and chemically robust interconnecting layer based on atomic layer-deposited tin oxide (SnO2) and solution-processed diluted poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), eliminating the need of widely reported parasitically absorbing metal recombination layers. Monolithic perovskite/organic tandem devices built on a metal-free interface (SnO2/PEDOT:PSS) compared to its counterpart (SnO2/metal/PEDOT:PSS) show no significant difference in PCE, but a remarkable enhancement in photostability. Furthermore, tandem solar cells were tested under outdoor conditions for 2 weeks, showing improved stability and solar power conversion than single-junction perovskite and organic devices, underscoring the potential of monolithic tandem solar cells.

Recent advances on monolithic perovskite‐organic tandem solar cells

“…Reproduced with permission. [ 77 ] Copyright 2022, American Chemical Society. (E) Schematic representation of the perovskite‐organic tandem device structure with ALD SnO x /Au functioning as recombination center.…”

“…Reproduced with permission. [ 77 ] Copyright 2022, American Chemical Society. (G) Design of perovskite‐organic tandem cell structure with a highlight on a simplified ICL design and (H) J–V curves of the champion tandem device with different scan directions.…”

“…The perovskite with the bandgap of 1.78 eV exhibits a V OC of 1.18 V. Consequently, a PCE of 17.6% for the tandem device was obtained using metal‐free ICL, which is comparable to the Ag‐based device (Figure 9F). [ 77 ] Very recently, Qiu et al optimized the WBG perovskite subcell through interfacial passivation to fabricate high‐performance perovskite‐organic tandem devices. The champion V OC of 1.33 eV could be obtained for the perovskite with bandgap of 1.77 eV.…”

Influence of Component Properties on the Photovoltaic Performance of Monolithic Perovskite/Organic Tandem Solar Cells: Sub‐Cell, Interconnecting Layer, and Photovoltaic Parameters

“…Reproduced with permission. [ 69 ] Copyright 2022, American Chemical Society. d) Long‐term stability of POTSCs under the illumination of a 5 mW cm −2 365 nm UV light (N 2 glovebox).…”

“…[77] As shown in Figure 10c, Xu et al found that, in the tandem configuration, WPSC is protected by the stack of ICL and the whole back cell from the diffusion of the top Ag electrode. [69] The interaction between the metal carrier recombination layer (Ag) and PEDOT:PSS is a major source of instability within tandem devices.…”