Rapid Oxidation of the Hole Transport Layer in Perovskite Solar Cells by A Low-Temperature Plasma

Wang, Yumeng; Qu, Hao; Zhang, Chunmei; Chen, Qiang

doi:10.1038/s41598-018-36685-6

Cited by 22 publications

(19 citation statements)

References 34 publications

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“…On the other hand, Ar was chemically inert. No noticeable oxidation and mobility enhancement were observed for the LiTFSI-doped spiro-OMeTAD HTL exposed to Ar plasma [20]. In addition, noticeable surface/structure modification, such as sputter etching was hardly observed under our low-energy plasma process within several seconds either (Figure 5), which was also demonstrated in another very recent work [29].…”

Section: Resultssupporting

confidence: 80%

“…Mobility of LiTFSI-doped spiro-OMeTAD was increased by more than one order of magnitude within less than 10 s plasma exposure. The results of mobility enhancement explained our previous work which demonstrated that ~10 s plasma exposure can result in the appreciable operation of PSC devices employing LiTFSI-doped spiro-OMeTAD HTL [20]. Typically, more than several hours of exposure to H 2 O, O 2 or dry air were necessary to functionalize LiTFSI-doped spiro-OMeTAD HTL and obtain desirable PSC device performance [10,12,14,15].…”

Section: Resultssupporting

confidence: 73%

“…Very recently, we have reported that oxygen or oxygen containing gas discharge plasma exposure could oxidize spiro-OMeTAD HTL effectively within seconds and made PSCs work well. The oxidation degree was analyzed qualitatively with UV-vis spectrum technique [20]. In this communication, hole-only devices were fabricated, and in-situ current density-voltage measurements were performed to investigate the real-time change in hole mobility of LiTFSI-doped spiro-OMeTAD films under plasma exposure.…”

Section: Introductionmentioning

confidence: 99%

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Plasma-Exposure-Induced Mobility Enhancement of LiTFSI-Doped Spiro-OMeTAD Hole Transport Layer in Perovskite Solar Cells and Its Impact on Device Performance

Zhao

Wang

et al. 2019

Materials

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2,2′,7,7′-Tetrakis(N,N-di-p-methoxyphenyl-amine)-9,9′-spirobifluorene (spiro-OMeTAD) film currently prevails as hole transport layer (HTL) employed in perovskite solar cells (PSCs). However, the standard preparation method for spin-coated, Lithium bis(trifluoromethylsulfony) imide (LiTFSI)-doped, spiro-OMeTAD HTL depends on a time-consuming and uncontrolled oxidation process to gain desirable electrical conductivity to favor device operation. Our previous work demonstrated that ~10 s oxygen or oxygen containing gas discharge plasma exposure can oxidize spiro-OMeTAD HTL effectively and make PSCs work well. In this communication, hole-only devices are fabricated and in-situ current density-voltage measurements are performed to investigate the change in hole mobility of LiTFSI-doped spiro-OMeTAD films under plasma exposure. The results reveal that hole mobility values can be increased averagely from ~5.0 × 10−5 cm2V−1s−1 to 7.89 × 10−4 cm2V−1s−1 with 7 s O2 plasma exposure, and 9.33 × 10−4 cm2V−1s−1 with 9 s O2/Ar plasma exposure. The effects on the photovoltaic performance of complete PSC devices are examined, and optical emission spectroscopy (OES) is used for a diagnostic to explain the different exposure effects of O2 and O2/Ar plasma. High efficiency, fine controllability and good compatibility with current plasma surface cleaning techniques may make this method an important step towards the future commercialization of photovoltaic technologies employing spiro-OMeTAD hole transport material.

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Section: Resultssupporting

confidence: 80%

Section: Resultssupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

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Plasma-Exposure-Induced Mobility Enhancement of LiTFSI-Doped Spiro-OMeTAD Hole Transport Layer in Perovskite Solar Cells and Its Impact on Device Performance

Zhao

Wang

et al. 2019

Materials

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“…The synthesis and study of the properties of new spiro‐fused carbo and heterocyclic compounds are one of the priority areas of investigations in organic chemistry, the results of which are of both theoretical interest and practical importance for a large number of researchers. These studies have been presented to the chemical community in original articles, [1–26] in thematic reviews, [27–35] as well as in review articles on the synthesis of some other heterocycles where spiro analogs are mentioned in one way or another [36,37] . The topic of spiro‐fused heterocycles is quite wide and therefore often touched upon when studying the chemistry of natural compounds, [38,39] in review articles [40] on the use of individual organic compounds in the synthesis of alkaloids, [41] in the enantioselective synthesis of hetero and carbocycles [42] or their macrocyclic analogs [43,44] …”

Section: Introductionmentioning

confidence: 99%

Advances in the Synthesis of Benzo‐Fused Spiro Nitrogen Heterocycles: New Approaches and Modification of Old Strategies

Гатауллин

2020

Helvetica Chimica Acta

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The review covers the results of studies published in the literature on the synthesis of spiro-linked heterocycles of the indole, quinoline, benzoxazine, benzothiazine, indenoquinoxaline, pyridopyrimidine, and acridine series. Possible approaches to the synthesis of spirocycles through a sequence of well-known Knoevenagel, Michael reactions, deamination cyclization of 1,2-dicarbonyl, CH-acid compounds, direct cycloaddition of activated olefins to isatins, 3-alkylideneindoles, 2-oxindoles, in situ generated azomethine ylides, indenoquinoxalines are analyzed. Attention is drawn to approaches to the preparation of spiro-fused compounds using reactions of intra-and intermolecular dearomatization of indoles. Recent advances in the synthesis of spiro-linked benzo heterocycles from derivatives of 2-olefin substituted anilines are summarized. The examples of the synthesis of spiro-fused heterocycles by means of metal complexes catalyzed decomposition of diazo compounds are given. Some syntheses of biologically active representatives are shown, as well as the use of transformations of spiroheterocycles in the preparation of other heterocycles.

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“…61 However, the presence of lithium cation was demonstrated to accelerate the oxidation process as well as the degradation of iodidebased solar cells, attributing the photovoltage losses to the presence of this ion. 62,63,64 In the same way, this result came into a controversy situation due to the recent study in 28 Chapter 1 bromide-based materials, suggesting different consequences in the performance of the PSCs depending on the halide compound employed. 58…”

Section: Spiro-ometadmentioning

confidence: 99%

Bulk and Interfacial Engineering to Enhance Photovoltaic Properties of Iodide and Bromide Perovskite Solar Cells

Alonso¹

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Hybrid halide perovskite solar cells (PSCs) have come to the forefront of photovoltaic technology due to their impressive power conversion efficiency (PCE) of up to 24% in lab scale achieved in no more than ten years of research. This high efficiency comes together with great advances regarding large-scale deposition methods and a critical enhancement of device stabilities. However, despite these major achievements, important challenges still remain in the shadows for commercialization of this technology. For example, the environmental impact concerning lead and tin components, the device stability under real operational conditions, numerous gaps regarding the fundamental physics of the material or the complex interactions occurring between the different layers in the complete solar device that are not fully understood.This thesis addresses issues related with the stability under real operation conditions and those associated with the interfacial interactions. For the first purpose, a robust method to fabricate high efficiency cells at any lab environment was developed through precursor´s formulation engineering. To accomplish the second goal, a clarification of the surface recombination dynamics, aided by optoelectronic and small perturbation techniques, was also provided via interlayer doping. Regarding these targets, two main perovskites materials based in methylammonium lead halides (MAPbX3) were optimized during the course of this thesis: MAPbI3 and MAPbBr3. A wide number of instrumental techniques were also applied for bulk material characterization purposes and to investigate the operational procedures involving the physical dynamics of the cell.To address the stability issues against atmospheric environments, a deeper understanding of perovskite crystallinity was mandatory. The role of the different precursors during the synthesis process and the control of the structural and chemical defects presented in the final film became crucial. The octahedral coordination chemistry regarding the basic structure of MAPbI3 served as starting point. An intensive study was carried out to clarify the influence of solvents on the formation of lead-halides complexes in solution and the consequences of this influence in the quality of the final perovskite film. This investigation concluded that a competition between solvent molecules and iodine is the responsible of the multi-iodide plumbates formed in solution and these species persist in the films acting as chemical defects that behaves as charge recombination pathways. Absorbance spectroscopy revealed the coordination capability sequence of the usual solvents employed in the perovskite formation: H2O > dimethylsulfoxide (DMSO) > N,N-dimethylformamide (DMF) > gamma-butyrolactone (GBL). In this series, water presents the strongest coordinative behaviour, due to its high polar character, and GBL the weakest coordinative solvent. The knowledge acquired here was used to develop formation criteria of high efficiency cells prepared under ambient conditions in the presence of ...

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Rapid Oxidation of the Hole Transport Layer in Perovskite Solar Cells by A Low-Temperature Plasma

Cited by 22 publications

References 34 publications

Plasma-Exposure-Induced Mobility Enhancement of LiTFSI-Doped Spiro-OMeTAD Hole Transport Layer in Perovskite Solar Cells and Its Impact on Device Performance

Plasma-Exposure-Induced Mobility Enhancement of LiTFSI-Doped Spiro-OMeTAD Hole Transport Layer in Perovskite Solar Cells and Its Impact on Device Performance

Advances in the Synthesis of Benzo‐Fused Spiro Nitrogen Heterocycles: New Approaches and Modification of Old Strategies

Bulk and Interfacial Engineering to Enhance Photovoltaic Properties of Iodide and Bromide Perovskite Solar Cells

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