Synergistic Coassembly of Highly Wettable and Uniform Hole‐Extraction Monolayers for Scaling‐up Perovskite Solar Cells

Abstract

All organic charge‐transporting layer (CTL)‐featured perovskite solar cells (PSCs) exhibit distinct advantages, but their scaling‐up remains a great challenge because the organic CTLs underneath the perovskite are too thin to achieve large‐area homogeneous layers by spin‐coating, and their hydrophobic nature further hinders the solution‐based fabrication of perovskite layer. Here, an unprecedented anchoring‐based coassembly (ACA) strategy is reported that involves a synergistic coadsorption of a hydrophilic ammonium salt CA‐Br with hole‐transporting triphenylamine derivatives to acquire scalable and wettable organic hole‐extraction monolayers for p–i–n structured PSCs. The ACA route not only enables ultrathin organic CTLs with high uniformity but also eliminates the nonwetting problem to facilitate large‐area perovskite films with 100% coverage. Moreover, incorporation of CA‐Br in the ACA strategy can distinctly guarantee a high quality of electronic connection via the cations' vacancy passivation. Consequently, a high power‐conversion‐efficiency (PCE) of 17.49% is achieved for p–i–n structured PSCs (1.02 cm2), and a module with an aperture area of 36 cm2 shows PCE of 12.67%, one of the best scaling‐up results among all‐organic CTL‐based PSCs. This work demonstrates that the ACA strategy can be a promising route to large‐area uniform interfacial layers as well as scaling‐up of perovskite solar cells.

Bonding Strength Regulates Anchoring‐Based Self‐Assembly Monolayers for Efficient and Stable Perovskite Solar Cells

“…These results are consistent with our previous report. [13] For PSCs based on the SO 3 H featured TPT-S6, the PCE was decreased to 16.16%, mainly owing to lower J SC (21.50 mA cm -2 ) and V OC (0.998 V) values. In contrast, devices based on the PO 3 H 2 featured TPT-P6 achieved a much higher PCE of 21.43%, with a promising V OC of 1.125 V and FF of 81.08%, which is among the best results of p-i-n structured PSCs and higher than the PCE of PSCs based on widely-used PTAA under the same fabrication condition (Figure S12, Supporting Information).…”

“…According to our previous work, the perovskite films deposited on TPT-C6 based molecular HTMs are very stable. [13] Therefore, the ASA HTMs-incorporated ITO substrates are responsible for the different PCE evolutions. We fabricated new PSCs based on the recycled substrates to evaluate their performance after aging.…”

“…[4][5][6][7][8][9][10] Recently, an anchoring based selfassembly (ASA) strategy has been demonstrated to be capable of constructing efficient hole transporting monolayers for highperformance p-i-n structured PSCs. [11][12][13] This process employs molecular HTMs comprising an anchoring group (such as carboxyl) that can spontaneously adsorb onto surface of oxide substrates to form a conformal monolayer coverage. Compared to traditional spin-coating or spray pyrolysis based thick hole-transporting layers (HTLs), the self-assemble monolayers have advantages of minimal material consumption and low parasitic absorption.…”

“…Moreover, the soaking based monolayer deposition is a low-cost and scalable fabrication route, which has been successfully implemented for mini-modules as well as large-area perovskite-silicon tandem solar cells. [13,14] Intriguingly, Wang et al found that the incorporation of anchoring groups (carboxyl) in molecular HTMs also improved the performance and processability for spin-casted organic HTLs. [4] These results suggest that anchoring groups are crucial for developing efficient molecular HTMs for p-i-n structured PSCs, although some anchoring-free molecular HTMs have been used in this kind of device.…”

Anchorable Perylene Diimides as Chemically Inert Electron Transport Layer for Efficient and Stable Perovskite Solar Cells with High Reproducibility

“…Previously, we proposed a strategy of anchoring involved assembly to construct robust and ultrathin molecular charge‐transporting layers for PSCs. [ 27–29 ] It addresses the earlier mentioned two issues simultaneously and enables a low‐cost and scalable fabrication route. Nevertheless, it is essential to advance the performance of organic ETLs‐based PSCs via further molecular engineering on the charge‐transporting units as well as the anchoring chains.…”