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Abstract The long‐term operational stability of perovskite solar cells (PSCs) remains a key challenge impeding their commercialization, particularly due to ambient environments (e.g., moisture, oxygen, heat)‐induced degradation. Carbon electrode‐based PSCs have emerged as cost‐effective and relatively stable alternatives to metal electrode‐based devices due to carbon materials' hydrophobic behavior, yet they still lag in both long‐term durability and power conversion efficiency (PCE). In this work, an ultrathin hydrophobic ligand‐modified core–shell Cd(S,Se)/ZnS quantum dots (QDs) capping layer is introduced as a multifunctional interfacial modifier for carbon‐electrode‐based PSCs. This oleic acid ligand‐modified QDs capping layer exhibits inherent hydrophobicity, effectively serving as a moisture barrier to retard perovskite degradation under ambient conditions. Furthermore, the strong interfacial bonding between the QDs and perovskite halide surfaces leads to efficient trap state passivation, reducing trap density and creating a more uniform electrical contact. The modified QDs/perovskite interface also features an elevated conduction band edge, promoting improved charge extraction. As a result, devices incorporating this quantum dot capping layer retain 98% of their initial PCE after 450 h of ambient aging and achieve a champion efficiency of 20.74%. This strategy highlights the potential of hydrophobic ligand‐modified chalcogenide QDs as surface modifiers to enhance both the stability and performance of carbon‐based PSCs, offering a promising route toward scalable fabrication of durable perovskite solar modules.
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Octylammonium Iodide Induced In‐situ Healing at “perovskite/Carbon” Interface to Achieve 85% RH‐moisture Stable, Hole‐Conductor‐Free Perovskite Solar Cells with Power Conversion Efficiency >19%
Abstract “Perovskite/carbon” interface is a bottle‐neck for hole‐conductor‐free, carbon‐electrode basing perovskite solar cells due to the energy mismatch and concentrated defects. In this article, in‐situ healing strategy is proposed by doping octylammonium iodide into carbon paste that used to prepare carbon‐electrode on perovskite layer. This strategy is found to strengthen interfacial contact and reduce interfacial defects on one hand, and slightly elevate the work function of the carbon‐electrode on other hand. Due to this effect, charge extraction is accelerated, while recombination is obviously reduced. Accordingly, power conversion efficiency of the hole‐conductor‐free, planar perovskite solar cells is upgraded by ≈50%, or from 11.65 (± 1.59) % to 17.97 (± 0.32) % (AM1.5G, 100 mW cm−2). The optimized device shows efficiency of 19.42% and open‐circuit voltage of 1.11 V. Meanwhile, moisture‐stability is tested by keeping the unsealed devices in closed chamber with relative humidity of 85%. The “in‐situ healing” strategy helps to obtain T80time of >450 h for the carbon‐electrode basing devices, which is four times of the reference ones. Thus, a kind of “internal encapsulation effect” has also been reached. The “in situ healing” strategy facilitates the fabrication of efficient and stable hole‐conductor‐free devices basing on carbon‐electrode.
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- Award ID(s):
- 1903962
- PAR ID:
- 10464250
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Small Methods
- Volume:
- 8
- Issue:
- 1
- ISSN:
- 2366-9608
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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