Suppressing defects through the synergistic effect of a Lewis base and a Lewis acid for highly efficient and stable perovskite solar cells

Wang, Shirong; Bi, Dongqin; Pellet, Norman; Xiao, Chuanxiao; Li, Zhen; Berry, Joseph J.; Zakeeruddin, Shaik M.; Zhu, Kai; Grätzel, Michaël

doi:10.1039/c8ee02252f

Cited by 280 publications

(204 citation statements)

References 52 publications

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“…Besides, C‐AFM has been carried out to investigate conductivity thereby unveiling the synergistic passivation effect of Lewis base and Lewis acid . The perovskite film with Lewis base (BrPh‐ThR) and Lewis acid (bis‐phenyl‐C 61 ‐butyric acid methyl ester (PCBM)) demonstrates an increased current under 1 V bias than that of pristine films.…”

Section: Applications Of C‐afm Techniquementioning

confidence: 99%

Emerging Conductive Atomic Force Microscopy for Metal Halide Perovskite Materials and Solar Cells

Zhang

et al. 2020

Advanced Energy Materials

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Metal halide perovskite materials, benefiting from a combination of outstanding optoelectronic properties and low‐cost solution‐preparation processes, show tremendous potential for optoelectronics and photovoltaics. However, the nanoscale inhomogeneities of the electronic properties of perovskite materials cause a number of difficulties, such as recombination, stability, and hysteresis, all of which seriously restrict device performance. Scanning probe microscopy, as a high‐resolution imaging technique, has been widely used to connect local properties and micro‐area morphologies to overall device performance. Conductive atomic force microscopy (C‐AFM) can realize a real‐space visualization of topography coupled with optoelectronic properties on a microscopic scale and thereby is uniquely suited to probe the local effects of perovskite materials and devices. The fundamental principles, alternative operation modes, and development of C‐AFM are comprehensively reviewed, and applications in perovskite solar cells (PSCs) for electronic transport behavior, ion migration and hysteresis, ferroelectric polarization, and facet orientation investigation are discussed. A comprehensive understanding and summary of up‐to‐date applications in PSCs is beneficial to further fully exploit the potential of such an emerging technique, so as to provide a novel and effective approach for perovskite materials analysis.

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Section: Applications Of C‐afm Techniquementioning

confidence: 99%

Emerging Conductive Atomic Force Microscopy for Metal Halide Perovskite Materials and Solar Cells

Zhang

et al. 2020

Advanced Energy Materials

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“…It is well known that the defects can act as charge recombination centers to induce severe energy loss, thereby reducing the device efficiency. [23][24][25] Therefore, it is imperative to seek an effective way to reduce the defects, especially at the PTLIs, for achieving the high-performance PSCs. [20][21][22] Moreover, several recent studies show that defects mainly present at the PTLIs (called interface defects), which are strongly associated with the energy level alignment, charge dynamics, photocurrent hysteresis, and the long-term operational stability.…”

mentioning

confidence: 99%

“…[46] In contrast, there is no detectable signals from metallic Pb in Poly(TA) modified perovskite, indicating that the under-coordinated lead atoms have been effectively reduced by Poly(TA). [25] Figure 4j shows the UV-vis absorption spectra of perovskite films with and without Poly(TA). Compared with the control sample, the glass/perovskite film with Poly(TA) has a stronger PL intensity and a longer lifetime, attributed to the reduced trap-assisted recombination.…”

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confidence: 99%

Efficient Bifacial Passivation with Crosslinked Thioctic Acid for High‐Performance Methylammonium Lead Iodide Perovskite Solar Cells

et al. 2019

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Organic-inorganic hybrid halide perovskite materials have been used in optoelectronic applications, including photodetectors, X-ray imaging, lasing, photocatalysis, lightemitting diodes, and so on. [1][2][3][4][5] Owing to their high optical absorption coefficient, low exciton binding energy, long charge carrier diffusion lengths, high photoluminescence (PL) quantum yield, suitable bandgap, and energy level, perovskite solar cells (PSCs) are emerging as promising candidates for the next-generation thin-film solar cells. [6][7][8][9][10][11] By optimizing the perovskite compositions, device structures, and deposition methods, power conversion efficiency (PCE) of PSCs has been dramatically increased from 3.8% in 2009 to the latest certified value of 25.2%, approaching the champion efficiency of the industry silicon solar cells. [12][13][14][15][16][17] The traditional lowtemperature solution-processing and fast crystallization method are widely used in synthesis of perovskite films, which inevitably introduce a large amount of defects into perovskite bulk and perovskite-transport layer interfaces (PTLIs). [18,19] Herein, PTLIs refer to the interfaces of both electron transport layer (ETL)/perovskite and perovskite/hole transport layer (HTL). It is well known that the defects can act as charge recombination centers to induce severe energy loss, thereby reducing the device efficiency. [18] Meanwhile, these trap states create conditions for the infiltration of moisture and oxygen into perovskite layer and subsequently seriously decrease the device stability. [20][21][22] Moreover, several recent studies show that defects mainly present at the PTLIs (called interface defects), which are strongly associated with the energy level alignment, charge dynamics, photocurrent hysteresis, and the long-term operational stability. [23][24][25] Therefore, it is imperative to seek an effective way to reduce the defects, especially at the PTLIs, for achieving the high-performance PSCs. Additive engineering [26][27][28][29][30][31][32][33][34] and interface engineering [35][36][37][38][39][40][41] have been regarded as effective strategies to reduce the defect density in PSCs, such as incorporating Phenyl-C61-butyric acid methyl ester (PCBM) [29] into perovskite layer to effectively passivate the defects and minimize the photocurrent hysteresis, inserting self-assembled monolayer of organic molecules with functional groups [36,37] into perovskite/ETL interface to suppress defects Defects, inevitably produced within bulk and at perovskite-transport layer interfaces (PTLIs), are detrimental to power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). It is demonstrated that a crosslinkable organic small molecule thioctic acid (TA), which can simultaneously be chemically anchored to the surface of TiO 2 and methylammonium lead iodide (MAPbI 3 ) through coordination effects and then in situ crosslinked to form a robust continuous polymer (Poly(TA)) network after thermal treatment, can be introduced into PSCs as a ...

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“…Thus, the use of the c‐Nb 2 O 5 /PC 61 BM bilayer ETL obviously reduces the defect density of the PVK film, highlighting the role of the c‐Nb 2 O 5 layer in passivating the traps or defects of the perovskite film. The passivation effect of c‐Nb 2 O 5 NS might be attributed to the presence of abundant Brønsted acid sites (i.e., surface OH groups) and Lewis acid sites (i.e., NbO 4 tetrahedra) on the (001) surface of c‐Nb 2 O 5 NS, which can protonate or accept an electron from the typical defects of PbX 3 ‐ or uncoordinated X ‐ (X = halide), and thus passivate these deep traps …”

Section: Resultsmentioning

confidence: 99%

“…Nevertheless, the inherent drawbacks of PC 61 BM have been reported as follows: 1) PC 61 BM cannot efficiently block the hole transport due to its shallow highest occupied molecular orbital (HOMO) with an energy level of ≈−6.0 eV . 2) PC 61 BM as a weak Lewis acid has an insufficient passivation effect . 3) PC 61 BM alone cannot efficiently block the iodine ions diffusion toward the cathode (i.e., Ag), resulting in fast cathode corrosion.…”

Section: Introductionmentioning

confidence: 99%

Solution‐Processed 2D Nb₂O₅(001) Nanosheets for Inverted CsPbI₂Br Perovskite Solar Cells: Interfacial and Diffusion Engineering

Han

Yuan

et al. 2019

Solar RRL

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Herein, solution‐processed 2D Nb2O5(001) nanosheets (c‐Nb2O5 NS) are prepared and combined with [6,6]‐phenyl‐C61‐butyric acid methyl ester (PC61BM) as an electron transport layer (ETL) for inverted inorganic CsPbI2Br perovskite solar cells (PeSCs). The PeSCs with a c‐Nb2O5/PC61BM bilayer ETL yield a high power conversion efficiency (PCE) up to 11.74%, remarkably outperforming the devices with only PC61BM (9.10%) and those with the state‐of‐the‐art ZnO/C60 ETL (10.65%) prepared under the same conditions. More importantly, the nonencapsulated PeSCs with c‐Nb2O5 exhibit a high thermal stability with only 20% PCE loss after 400 h thermal aging at 85 °C. Such an impressive performance and a high stability can be attributed to the introduction of c‐Nb2O5(001) NS with favorable band levels, strong acid nature, and the small lattice fringe spacing along the large lateral (001) surface, which not only facilitate the electron transport, blocking the hole transport, but also contribute to defect passivation and retard the iodine ions diffusion toward the Ag electrode. This study thus provides a deeper insight for the interfacial design in inverted inorganic PeSCs and contributes to PCE improvement in the future.

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Suppressing defects through the synergistic effect of a Lewis base and a Lewis acid for highly efficient and stable perovskite solar cells

Abstract: The synergistic combination of a Lewis base and a Lewis acid enables perovskite solar cells with high efficiency and stability.

Cited by 280 publications

References 52 publications

Emerging Conductive Atomic Force Microscopy for Metal Halide Perovskite Materials and Solar Cells

Emerging Conductive Atomic Force Microscopy for Metal Halide Perovskite Materials and Solar Cells

Efficient Bifacial Passivation with Crosslinked Thioctic Acid for High‐Performance Methylammonium Lead Iodide Perovskite Solar Cells

Solution‐Processed 2D Nb₂O₅(001) Nanosheets for Inverted CsPbI₂Br Perovskite Solar Cells: Interfacial and Diffusion Engineering

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Suppressing defects through the synergistic effect of a Lewis base and a Lewis acid for highly efficient and stable perovskite solar cells

Abstract: The synergistic combination of a Lewis base and a Lewis acid enables perovskite solar cells with high efficiency and stability.

Cited by 280 publications

References 52 publications

Emerging Conductive Atomic Force Microscopy for Metal Halide Perovskite Materials and Solar Cells

Emerging Conductive Atomic Force Microscopy for Metal Halide Perovskite Materials and Solar Cells

Efficient Bifacial Passivation with Crosslinked Thioctic Acid for High‐Performance Methylammonium Lead Iodide Perovskite Solar Cells

Solution‐Processed 2D Nb2O5(001) Nanosheets for Inverted CsPbI2Br Perovskite Solar Cells: Interfacial and Diffusion Engineering

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Solution‐Processed 2D Nb₂O₅(001) Nanosheets for Inverted CsPbI₂Br Perovskite Solar Cells: Interfacial and Diffusion Engineering