Interfacial Structure and Composition Managements for High‐Performance Methylammonium‐Free Perovskite Solar Cells

Li, Shunde; Qiao, Zhiqiang; Wang, Xiao; Cheng, Lei; Zhai, Yufeng; Xu, Qiaofei; Li, Zhimin; Chen, Gang

doi:10.1002/adfm.202005846

Cited by 28 publications

(30 citation statements)

References 59 publications

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“…The effect of Cs content in FAPbI 3 was investigated in our previous work, [ 21 ] where we found an optimal doping ratio of 10% to form the Cs 0.10 FA 0.90 PbI 3 perovskite (noted CsFA hereinafter). Furthermore, the beneficial effect of adding a small amount of Rb into CsFAPI was reported in the literature, [ 31,32 ] with an optimal doping ratio of 5% that we have retained in the present work to form the Rb 0.05 Cs 0.10 FA 0.85 PbI 3 perovskite (noted RbCsFA hereinafter). Then, the influence of the addition of KI on the performance of the perovskite solar cell was investigated and the optimum amount of this metal halide was found at 5% (the details of this study are reported in Part A, Supporting Information).…”

Section: Resultsmentioning

confidence: 63%

Controlling the Formation Process of Methylammonium‐Free Halide Perovskite Films for a Homogeneous Incorporation of Alkali Metal Cations Beneficial to Solar Cell Performance

Zheng

Zhu

Yan

et al. 2022

Advanced Energy Materials

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efficiency (PCE) for a perovskite solar cell (PSC) is 25.7%. [12] However, PSCs still need further progress to overcome instability issues caused by moisture, oxygen, and heat, while maintaining or improving their PCE. The composition of ABX 3 based 3D halide perovskite greatly affects the overall performance of perovskite solar cells. Different components can bring desired properties, such as improved optical properties or structural stability. To achieve better performance of PSC, perovskite materials composition has been complexified by combining several A + monovalent elemental and organic cations, from double-cation (e.g., MA-FA, [13,14] Cs/FA, [15,16] Rb/FA, [17] MA + being methylammonium and FA + being formamidinium) to triple-cation (e.g., Cs/MA/ FA, [8,18,19] Rb/MA/FA, [20] K/Cs/FA [21] ), and quadruple-cation (Rb/Cs/MA/FA [18,22] ). The incorporation of other cations, namely MA + , Cs + , Rb + and K + , aims at alleviating the formation of photo inactive δ-FAPbI 3 phase and/or suppress defects in perovskite film. Although MAbased perovskite solar cells can achieve very high PCE, [23][24][25] the presence of MA can favor PVK degradation since MA is easily released and decomposed under heating and humid atmosphere. A lot of works have been dedicated to enhancing the stability of the black α-FAPbI 3 phase, notably to its entropic stabilization by incorporating Cs. [18,19] The structural engineering by introducing elemental monovalent cations can shed light on the long-term stability of PSCs. For instance, introducing another alkali metal, Rb (same column as Cs and K), into FAPbI 3 perovskite has been shown to enhance both the photovoltaic performance and the moisture stability. [17] Moreover, the nonradiative loss and photoinduced ion migration in perovskite film are significantly reduced by using potassium halide to passivate the defects at near surface and grain boundaries. [16,26] All these considerations led us to develop multialkali metal cations (m-AMCs) KRbCsFAPbI 3 3D perovskites. However, phase segregation might happen on m-AMCs perovskite films and the distribution of each element is worth noting. Especially, the homogeneous distribution of Rb + is sought for high stability and performances. [27] Incorporating multiple cations of the 1A alkali metal column of the periodic table (K + /Rb + /Cs + ) to prepare perovskite films is promising for boosting photovoltaic properties but requires a uniform distribution. The effects of NH 4 Cl additives and alkali metal cations (K + /Rb + /Cs + ) on the one-step formation process of methylammonium-free, formamidinium-based, iodide perovskite films are analyzed in a step-by-step manner. NH 4 Cl improves the solubility of PbI 2 in solution by forming an intermediate and then favors the perovskite phase formation. Moreover, during the annealing process, this additive is shown to increase grain size, to improve crystallinity and to suppress PbI 2 formation. K at low concentration is always homogeneously distributed across the film thickness. On the other hand, C...

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Section: Resultsmentioning

confidence: 63%

Controlling the Formation Process of Methylammonium‐Free Halide Perovskite Films for a Homogeneous Incorporation of Alkali Metal Cations Beneficial to Solar Cell Performance

Zheng

Zhu

Yan

et al. 2022

Advanced Energy Materials

View full text Add to dashboard Cite

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“…[ 18,19 ] However, the full elimination of MA + must be targeted for a better stabilization. [ 20–33 ] The most popular approach for MA‐free PSCs consists in replacing MA + by Cs + and/or by Rb + cations, two alkali metals. [ 20,21,31–33 ] Several authors have developed interfacial engineering for boosting the performances of the devices.…”

Section: Introductionmentioning

confidence: 99%

“…[ 20,21,31–33 ] Several authors have developed interfacial engineering for boosting the performances of the devices. [ 22–24,33 ] However, in the absence of MA, PSCs usually show inferior PCEs due to an insufficient quality of the PVK material. Increasing the material crystallinity and passivating defects must be targeted.…”

Section: Introductionmentioning

confidence: 99%

A Coadditive Strategy for Blocking Ionic Mobility in Methylammonium‐Free Perovskite Solar Cells and High‐Stability Achievement

2021

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Herein, the synthesis of methylammonium‐free and bromide‐free CsxFA1−xPbI3 (FA for formamidinium) perovskite (PVK) photovoltaic layers with intrinsic outstanding properties in terms of crystallinity, defect waiving/passivation, and ionic mobility blocking by using a coadditives approach is described. It consists in mixing two chloride additives in the PVK precursor solution: potassium chloride (KCl) and ammonium chloride (NH4Cl). KCl favors the lead iodide (PbI2) precursor solubilization and results in a purer PVK phase. NH4Cl allows the control of the crystallization growth speed, leading to the formation of large crystal grains and well‐crystallized layers. By the glow‐discharge optical emission spectroscopy (GD‐OES) technique, it is directly visualized that potassium incorporated in the whole film blocks the iodide mobility by defect passivation. Also, the reduction (or suppression) of iodide mobility and the reduction (or suppression) of the J–V curve hysteresis is clearly correlated. It is found that blocking the ionic mobility is insufficient to fully stabilize the halide perovskite material which also requires the crystallization monitoring carried out in parallel by the second additive. It resulted in Cs0.1FA0.9PbI3 cells with a stabilized power conversion efficiency (PCE) of 20.02% and with superior stability.

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“…demonstrated that CsPbI 3 could not cation exchange with PEAI to form 2D PVK layer, the PEAI on the CsPbI 3 layer just formed a surface termination layer (Figure 12E), which enhanced phase stability and moisture resistance (Figure 12F). Li et al [197] . investigated the surface treatment of methylammonium‐free PVK layers by PAI and propane‐1,3‐diammonium (PDA) iodide.…”

Section: Halides At the Interfaces Of Pscsmentioning

confidence: 99%

Chlorides, other Halides, and Pseudo‐Halides as Additives for the Fabrication of Efficient and Stable Perovskite Solar Cells

2021

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Perovskite solar cells (PSCs) are attracting a tremendous attention from the scientific community due to their excellent power conversion efficiency, low cost, and great promise for the future of solar energy. The best PSCs have already achieved a certified power conversion efficiency (PCE) of 25.5 % after an unprecedented rapid performance rise. However, high requirements with respect to large area, high‐efficiency devices, and stability are still the challenges. Major efforts, especially for achieving a high degree of chemical control, have been made to reach these targets. The use of halide additives has played a critical role in improving the efficiency and stability. The present paper reviews the important breakthroughs in PSC technologies made by using halide additives, especially chloride, and pseudo‐halide additives for the preparation of the perovskite layers, other layers, and interfaces of the devices. These additives help perovskite (PVK) crystallization and layer morphology control, grain boundary reduction, bulk and interface defects passivation, and so on. Normally, these halide additives play different roles depending on their categories and their location. Herein, recent progresses made due to additives employment in every possible layer of PSCs are reviewed, with focus on chloride, other halides, and pseudo‐halides as additives in PVK films, halide additives in carrier transport layers, and at PVK‐contact interfaces. Finally, an outlook of engineering of these additives in PSC progress is given.

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Interfacial Structure and Composition Managements for High‐Performance Methylammonium‐Free Perovskite Solar Cells

Cited by 28 publications

References 59 publications

Controlling the Formation Process of Methylammonium‐Free Halide Perovskite Films for a Homogeneous Incorporation of Alkali Metal Cations Beneficial to Solar Cell Performance

Controlling the Formation Process of Methylammonium‐Free Halide Perovskite Films for a Homogeneous Incorporation of Alkali Metal Cations Beneficial to Solar Cell Performance

A Coadditive Strategy for Blocking Ionic Mobility in Methylammonium‐Free Perovskite Solar Cells and High‐Stability Achievement

Chlorides, other Halides, and Pseudo‐Halides as Additives for the Fabrication of Efficient and Stable Perovskite Solar Cells

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