Perovskite
solar cells (PSCs) with organic hole transporting layers
(o-HTLs) have been widely studied due to their convenient solution
processing, but it remains a big challenge to improve the hole mobilities
of commercially available organic hole transporting materials without
ion doping while maintaining the stability of PSCs. In this work,
we demonstrated that the introduction of perovskite quantum dots (QDs)
as interlayers between perovskite layers and dopant-free o-HTLs (P3HT,
PTAA, Spiro-OMeTAD) resulted in a significantly enhanced performance
of PSCs. The universal role of QDs in improving the efficiency and
stability of PSCs was validated, exceeding that of lithium doping.
After a deep examination of the mechanism, QD interlayers provided
the multifunctional roles as follows: (1) passivating the perovskite
surface to reduce the overall amount of trap states; (2) promoting
hole extraction from perovskite to dopant-free o-HTLs by forming cascade
energy levels; (3) improving hole mobilities of dopant-free o-HTLs
by regulating their polymer/molecule orientation. What is more, the
thermal/moisture/light stabilities of dopant-free o-HTLs-based PSCs
were greatly improved with QD interlayers. Finally, we demonstrated
the reliability of the QD interlayers by fabricating large-area solar
modules with dopant-free o-HTLs, showing great potential in commercial
usage.
FACs‐based (FA+, formamidinium and Cs+, cesium) perovskite solar cells have gained great attention due to their remarkable light and thermal stabilities toward practical application of perovskite modules. However, the moisture instability and difficulty in scalable fabrication are still the main obstacles blocking their photovoltaic applications in current status. Here, the employment of novel interaction between crown ether with metal cations is introduced to tailor the uniform growth and inhibit moisture invasion during the crystallization of α‐phase FACsPbI3, yielding the successful synthesis of high‐quality perovskite films in a large scale. Consequently, perovskite solar cells (PSC) modules in the total area of 4 × 4 and 10 × 10 cm2 are readily fabricated with respective champion efficiencies of 16.69% and 13.84% and excellent stability over 1000 h. This facile scaling‐up strategy assisted by crown ether has shown great promise for pursuing efficient and highly stable large‐area PSC modules.
In this Letter, the electrochemical visualization of hydrogen peroxide inside one cell was achieved first using a comprehensive Au-luminol-microelectrode and electrochemiluminescence. The capillary with a tip opening of 1-2 μm was filled with the mixture of chitosan and luminol, which was coated with the thin layers of polyvinyl chloride/nitrophenyloctyl ether (PVC/NPOE) and gold as the microelectrode. Upon contact with the aqueous hydrogen peroxide, hydrogen peroxide and luminol in contact with the gold layer were oxidized under the positive potential resulting in luminescence for the imaging. Due to the small diameter of the electrode, the microelectrode tip was inserted into one cell and the bright luminescence observed at the tip confirmed the visualization of intracellular hydrogen peroxide. The further coupling of oxidase on the electrode surface could open the field in the electrochemical imaging of intracellular biomolecules at single cells, which benefited the single cell electrochemical detection.
The incorporation of a Br-containing tetrabutylammonium salt into perovskite precursors demonstrates superior advantages in both crystallization and large-area uniformity control during the scalable blade-coating of perovskite films.
Perovskite solar cells are the fastest‐growing photovoltaic technology in recent years. However, together with the stability, the low‐cost and high‐quality preparation of large‐area modules still limits their commercialization process. Herein, a scalable and high‐performance ZnOSnO2 cascade double‐layer electron transport layer (ETL) for efficient and stable perovskite modules is reported. The cascaded ETL is fabricated using a simple spray pyrolysis coating combined with the blade coating process, which not only effectively improves the interface stability by avoiding the protonation of ZnO to maintain its high electron mobility, but also provides a much smoother surface for the crystallization of perovskites. In addition, the well‐matched conduction band level between SnO2 and perovskites ensures the improvement of open‐circuit voltage. Subsequently, combined with the blade‐coated perovskite layer and hole transport layer film, large‐area planar perovskite modules are successfully prepared. These high‐quality films enable the perovskite solar modules to achieve impressive efficiencies of 17.8% in the module size 6 × 6 cm2 and 16.6% in a size of 10 × 10 cm2. The obtained module also shows excellent reproducibility and stability. The high‐performance ETL and the related deposition method developed in this work are promising for applications in the industrial scalable perovskite modules’ fabrication.
Perovskite solar cells (PSCs) have attracted great interest in recent decade, however, stability issue and large‐scale application still remain as roadblocks to their practical applications. To settle aforementioned issues, metal diffusion and ion migration should be controlled to improve long‐term operational stability. Herein, cubic zinc metatitanate (ZTO) is optimized and improved by segregating with surface sulfidation. The sulfurized electron transporting layer, label as ZTO‐ZnS, based PSCs achieved an amazing power conversion efficiency (PCE) of 21.3%. A large‐area module (8.0 cm2 active area) based on ZTO‐ZnS is also developed with 15.9% PCE. Furthermore, combining with inorganic CuI hole transporting layer and carbon counter electrode, metal diffusion, and ion migration effect are eliminated drastically in ZTO‐ZnS‐based PSCs. The combined PSC devices can easily keep more than 85% initial PCE after 1 000 h at 85 °C in air with a relative humidity of 85% under maximum power point and continuous AM 1.5G illumination. The persistence in stability is investigated and revealed fully by energy dispersive spectrometer analysis, attributing to the PSC structure which blocks the metal diffusion and ion migration in the devices. A big step forward industrialization and commercialization for PSCs is made.
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