Nanoscale localized contacts for high fill factors in polymer-passivated perovskite solar cells

Abstract

Polymer passivation layers can improve the open-circuit voltage of perovskite solar cells when inserted at the perovskite–charge transport layer interfaces. Unfortunately, many such layers are poor conductors, leading to a trade-off between passivation quality (voltage) and series resistance (fill factor, FF). Here, we introduce a nanopatterned electron transport layer that overcomes this trade-off by modifying the spatial distribution of the passivation layer to form nanoscale localized charge transport pathways through an otherwise passivated interface, thereby providing both effective passivation and excellent charge extraction. By combining the nanopatterned electron transport layer with a dopant-free hole transport layer, we achieved a certified power conversion efficiency of 21.6% for a 1-square-centimeter cell with FF of 0.839, and demonstrate an encapsulated cell that retains ~91.7% of its initial efficiency after 1000 hours of damp heat exposure.

Solar cell efficiency tables (Version 58)

“…The cell uses a nanostructured TiO 2 electron transport layer that modifies the spatial distribution of the passivation layer to form nanoscale localised charge transport pathways through an otherwise passivated interface, therefore providing both effective passivation and good charge extraction. 16 The third new result is a landmark 20.1% efficiency for a 64-cm 2 perovskite minimodule fabricated by Wuxi Utmost Light Technology Co. Ltd (UtmoLight) 17 and measured at the Japan Electrical Safety and Environment Technology Laboratories (JET). Along with other emerging technologies, perovskite cells and modules may not demonstrate the same level of stability as more established cell technologies, with references to this aspect given in the footnotes to Table 1.…”

Single-crystalline TiO2 Nanoparticles for Narrowing the Scalability Gap towards Stable and Efficient Perovskite Modules

“…The major obstacles to narrow the gap in e ciency between the small devices and large-area modules come from the signi cant resistive loss 7,8 and the complexity of the processes for achieving high-quality large-area perovskite lms. 4,5,6,9 Although high-performance devices based on a planar structure were achieved 1,2,10 , utilization of mesoporous TiO 2 (m-TiO 2 ) skeletons has been demonstrated as an e cient structure in most high-e ciency devices 7,11,12 , because of a large TiO 2 /perovskite contact area for interfacial charge transfer and suppressed charge recombination over planar perovskite solar cells 13,14 . A detailed photoelectrical model 15 was proposed to rationalize and quantify the ll factor (FF) losses of devices (Fig.…”

The Main Progress of Perovskite Solar Cells in 2020–2021

“…This detrimental effect will become more obvious in the case of large-area devices. In order to balance the improvement of V OC and FF, Peng et al designed a nanoscale localized contact at the polymer-passivated perovskite/TiO 2 interface to realize a higher FF for 1 cm 2 PSCs [ 37 ]. They deposited a nanopatterned electron-selective TiO 2 layer via atomic-layer deposition (ALD) to form nanorod-like charge transport channels through the passivated interface (the device structure is shown in Fig.…”

“…d Experimental J-V curves of the PSCs based on planar (reference cell) and the TiO 2 nanopatternstructure, 300 nm pitch represents the TiO 2 nanorods with a spacing of 300 nm in devices, the inset shows that about 30% of the nanorod is coated with insulating passivation layer. Reproduced with permission from Ref [37]. Copyright 2020 AAAS…”