Suppressing Vacancy Defects and Grain Boundaries via Ostwald Ripening for High‐Performance and Stable Perovskite Solar Cells

Yang, Yuqian; Wu, Jihuai; Wang, Xiaobing; Guo, Qiyao; Liu, Xuping; Sun, Weihai; Wei, Yuelin; Huang, Yunfang; Huang, Miaoliang; Lin, Jianming; Chen, Hongwei; Wei, Zhanhua

doi:10.1002/adma.201904347

Cited by 184 publications

(165 citation statements)

References 57 publications

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“…The generation of intermediate MAI-additive-PbI 2 complexes allowed for the formation of large clusters in solution that can effectively reduce the energy barrier ( Δ G) and regulate rapid nucleation and crystal growth at the lower annealing temperature. Moreover, the growth of small grains into larger ones suffers from Ostwald ripening [ 40 , 41 ], which is limited either by the mass transport (diffusion-controlled) or by their attachment on the larger grains (interface-reaction controlled). In the case of using urea or biuret as additives, the strong interaction between the additives and the precursor drives the free “monomers” (PbI 2 and MAI) to the grain boundaries where the additives are attached, speeding up the crystal growth ( Figure 1(c) , III).…”

Section: Resultsmentioning

confidence: 99%

All-in-One Deposition to Synergistically Manipulate Perovskite Growth for High-Performance Solar Cell

Zhang

Wang

et al. 2020

Research

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Nonradiative recombination losses originating from crystallographic distortions and issues occurring upon interface formation are detrimental for the photovoltaic performance of perovskite solar cells. Herein, we incorporated a series of carbamide molecules (urea, biuret, or triuret) consisting of both Lewis base (–NH2) and Lewis acid (–C=O) groups into the perovskite precursor to simultaneously eliminate the bulk and interface defects. Depending on the different coordination ability with perovskite component, the incorporated molecules can either modify crystallization dynamics allowing for large crystal growth at low temperature (60°C), associate with antisite or undercoordinated ions for defect passivation, or accumulate at the surface as an energy cascade layer to enhance charge transfer, respectively. Synergistic benefits of the above functions can be obtained by rationally optimizing additive combinations in an all-in-one deposition method. As a result, a champion efficiency of 21.6% with prolonged operational stability was achieved in an inverted MAPbI3 perovskite solar cell by combining biuret and triuret additives. The simplified all-in-one fabrication procedure, adaptable to different types of perovskites in terms of pure MAPbI3, mixed perovskite, and all-inorganic perovskite, provides a cost-efficient and reproducible way to obtain high-performance inverted perovskite solar cells.

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Section: Resultsmentioning

confidence: 99%

All-in-One Deposition to Synergistically Manipulate Perovskite Growth for High-Performance Solar Cell

Zhang

Wang

et al. 2020

Research

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“…Pb 2+ is prone to be reduced to metallic Pb 0 upon heating or illumination, as previously reported. [ 31,32 ] As shown in Figure S1d in the Supporting Information, it is obvious that the Pb 0 peaks of 10% doped GuaSM PVK film at 136.9 and 141.7 eV show highest intensity. On the contrary, the low intensity of Pb 0 peaks in 2% GuaSM‐doped PVK film further demonstrates that 2% GuaSM doping is not enough to generate significant Pb 0 .…”

Section: Resultsmentioning

confidence: 99%

Additive Engineering by Bifunctional Guanidine Sulfamate for Highly Efficient and Stable Perovskites Solar Cells

Liu

Yang

et al. 2020

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High efficiency and good stability are the challenges for perovskite solar cells (PSCs) toward commercialization. However, the intrinsic high defect density and internal nonradiative recombination of perovskite (PVK) limit its development. In this work, a facile additive strategy is devised by introducing bifunctional guanidine sulfamate (GuaSM; CH6N3+, Gua+; H2N−SO3−, SM−) into PVK. The size of Gua+ ion is suitable with Pb(BrI)2 cavity relatively, so it can participate in the formation of low‐dimensional PVK when mixed with Pb(BrI)2. The O and N atoms of SM− can coordinate with Pb2+. The synergistic effect of the anions and cations effectively reduces the trap density and the recombination in PVK, so that it can improve the efficiency and stability of PSCs. At an optimal concentration of GuaSM (2 mol%), the PSC presents a champion power conversion efficiency of 21.66% and a remarkably improved stability and hysteresis. The results provide a novel strategy for highly efficient and stable PSCs by bifunctional additive.

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“…In the literature, metallic Pb 0 is usually restrained via additive engineering by introducing an ion redox shuttle [ 30b,32 ] or Lewis bases possessing high electron cloud density, [ 33 ] whereas there are few reports that surface modification can reduce the metallic Pb 0 peaks. As mentioned, the metallic Pb 0 peaks could simply be due to the fact that highly unsaturated Pb shows metallic characteristics.…”

Section: Figurementioning

confidence: 99%

High‐Pressure Nitrogen‐Extraction and Effective Passivation to Attain Highest Large‐Area Perovskite Solar Module Efficiency

et al. 2020

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Organometallic halide perovskite has attracted extensive interest by virtue of its stunning defect tolerance, small excitonbinding energy, [1] high absorption coefficient, [2] extremely low trap-state density, [3] and long carrier diffusion length. [4] In just a few years, the power conversion efficiency (PCE) of lab-scale perovskite solar cells (PSCs) has swiftly skyrocketed from 3.8% to 25.2%, [5] outperforming all other thin film solar cells. Nevertheless, for the highest efficiency devices, all functional layers except the evaporated metal electrodes were fabricated by a non-scalable spin coating process. Thus, fabricating large-area high-efficiency PSCs remains challenging, and it is therefore imperative to develop continuous, large-area deposition processes for potential scalable production. To address this issue, quite a few potentially scalable techniques, such as spray deposition, [6] inkjet printing, [7] brush-painting deposition, [8] blade coating, [9] and slot-die coating [10] have been exploited in support of producing PSCs via low-temperature solution processes. Among them, slot-die coating is the most competitive because of its ability to precisely control largearea uniformity at the desired thinness of ≈500 nm with welldefined edges as required by module design. Additionally, high material utilization is another aspect of its attractiveness. In 2015, Hwang et al. ventured to deposit PbI 2 films via slot-die coating and then convert them to perovskites through methylammonium iodide solution immersion. [11] Kim et al. further optimized this method by inhibiting PbI 2 crystallization and increased the PCE to 18.3%. [12] This deposition/ conversion strategy can indeed increase the controllability of slot-die coating and decrease the operational difficulty. However, it suffers from incomplete material conversion and a high percentage of soaking solution wastage, which are incompatible with practical large-scale fabrication. Therefore, attention has increasingly turned to the one-step slot-die coating technique, [13] but it usually produces a rough perovskite layer with poor surface coverage because its demand for fast evaporation of solvent is not always assured as in the spin-coating process. To compensate for this drawback, substrate heating, anti-solvent engineering, and gas treatment were established Slot-die coating holds advantages over other large-scale technologies thanks to its potential for well-controlled, high-throughput, continuous roll-to-roll fabrication. Unfortunately, it is challenging to control thin.film uniformity over a large area while maintaining crystallization quality. Herein, by using a high-pressure nitrogen-extraction (HPNE) strategy to assist crystallization, a wide processing window in the well-controlled printing process for preparing high-quality perovskites is achieved. The yellow-phase perovskite generated by the HPNE acts as a crucial intermediate phase to produce large-area high-quality perovskite film. Furthermore, an ionic liquid is developed to passivate the perov...

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Suppressing Vacancy Defects and Grain Boundaries via Ostwald Ripening for High‐Performance and Stable Perovskite Solar Cells

Cited by 184 publications

References 57 publications

All-in-One Deposition to Synergistically Manipulate Perovskite Growth for High-Performance Solar Cell

All-in-One Deposition to Synergistically Manipulate Perovskite Growth for High-Performance Solar Cell

Additive Engineering by Bifunctional Guanidine Sulfamate for Highly Efficient and Stable Perovskites Solar Cells

High‐Pressure Nitrogen‐Extraction and Effective Passivation to Attain Highest Large‐Area Perovskite Solar Module Efficiency

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