Origins of High Performance and Degradation in the Mixed Perovskite Solar Cells

Heo, Sung; Seo, Gabseok; Lee, Yonghui; Seol, Minsu; Kim, Seong Heon; Yun, Dong‐Jin; Kim, Yong‐Su; Kim, Kihong; Lee, Jun-Ho; Lee, Jooho; Jeon, Woo Sung; Shin, Jai Kwang; Park, Jucheol; Lee, Dong‐Wook; Nazeeruddin, Mohammad Khaja

doi:10.1002/adma.201805438

Cited by 45 publications

(30 citation statements)

References 28 publications

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“…The degradation of PSCs could originate from the degradation of the perovskite material, the interfacial materials, electrodes, or a combination of all. [ 18,19 ] To get insight into these issues, it is necessary to apply different characterization techniques that provide direct or indirect information about the degradation processes in the bulk, electrodes, and interfaces of the devices.…”

Section: Introductionmentioning

confidence: 99%

Impedance Spectroscopy of Perovskite Solar Cells: Studying the Dynamics of Charge Carriers Before and After Continuous Operation

Hailegnaw

Sariciftci

Scharber

2020

Physica Status Solidi (a)

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The issue of long‐term stability is one of the main obstacles challenging the progress of perovskite solar cells (PSCs). To alleviate this issue, a thorough understanding of the degradation mechanisms of the device is required. Herein, electrochemical impedance measurements in combination with maximum power point (MPP) tracking are applied to characterize PSCs, aiming to gain an understanding of the charge carrier dynamics in the photoactive bulk and at the contact‐absorber‐interfaces under operation. Electrochemical impedance spectroscopy (EIS) results show that the device charge transport resistance and interface capacitance associated with charge accumulation at the interfaces are both increasing upon continuous operation. This suggests ion migration from the photoactive perovskite layer to the charge transport layer interfaces leaving defects in the bulk. This suggests that reduction of the device performance upon continuous operation is mainly related to the changes in the bulk of the photoactive perovskite film and ions migration.

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Section: Introductionmentioning

confidence: 99%

Impedance Spectroscopy of Perovskite Solar Cells: Studying the Dynamics of Charge Carriers Before and After Continuous Operation

Hailegnaw

Sariciftci

Scharber

2020

Physica Status Solidi (a)

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“…The peak of the trap density of the state decreased from ≈1.4 × 10 17 cm −3 eV −1 (at 0.188 eV) to ≈1.1 × 10 16 cm −3 eV −1 (at 0.383 eV), consistent with previous reports of a decline of trap states after photo-aging. [54,55] Space charge limited current (SCLC) measurement was also conducted to compare changes in electron trap densities by using electron-only type samples as shown in Figure S13, Supporting Information. [56,57] The electron trap density increased significantly in 1.3 m thin-films, whereas that of 1.1 m thin-film remained stable.…”

Section: Resultsmentioning

confidence: 99%

Investigation of Defect‐Tolerant Perovskite Solar Cells with Long‐Term Stability via Controlling the Self‐Doping Effect

Cho

Byeon

Jeong

et al. 2021

Advanced Energy Materials

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outstanding opto-electronic properties, including the controllable bandgap and long charge-carrier diffusion length. [1][2][3][4][5][6][7] Despite these excellent properties of organic-inorganic hybrid halide perovskite materials, there are still many challenging issues to overcome before commercialization mostly related to long-term stability. Various studies have previously suggested that oxygen, moisture, and heat have been considered as extrinsic factors of the degradation of PSCs. [8][9][10][11][12][13] To eliminate the external factors for degradation, various encapsulation techniques have been used including edge sealant, polymer-based lamination, and direct deposition of thinfilm encapsulation methods. [14][15][16] However, even encapsulated PSCs still often exhibit rapid degradation, particularly under illumination conditions, implying the importance of intrinsic factors in degradation.Recent studies have suggested that the trapping of excess charge-carriers and the migration of ions and point-defects are major intrinsic factors of degradation. [17][18][19][20][21] In addition, illuminated conditions promote photo-induced ion migration and secondary phase formation. [22][23][24][25] Despite understanding the excess charge-carriers and ion migrations would ultimately be a hindrance to the long-term stability of PSCs, it still remains unclear how these intrinsic factors of degradation affect the defect states and intrinsic properties of perovskite. The defects of perovskite can be adjusted to some extent depending on the fabrication method and environment. [26][27][28][29][30] Experimental studies have shown that the Fermi level (E F ) of the perovskite layer can be tuned through the self-doping effect by fabrication methods (e.g., spin-coating, thermal evaporation, I 2 vapor exposure, etc.) and the ratio between cations and anions. [29][30][31][32][33][34] Though the focus has been on tuning the selfdoping effect to enhance the PCEs, maximizing them does not necessarily correlate with the stability of PSCs. Recent studies suggest that fabrication conditions that increase the PCEs may compromise stability. [35] Therefore, fundamental investigations of the impact of intrinsic defects on long-term stability via controlling the self-doping effect are necessary.In this study, we elucidate the intrinsic photo-aging mechanism by observing the change in intrinsic properties due to the initial defect states. To clarify the impact of the defects on the photo-aging mechanism solely by the intrinsic factors, we rule out the extrinsic degradation factors by aging the PSCs Although there have been significant advances in the stability of perovskite solar cells through encapsulation techniques to remove extrinsic degradation factors, such as moisture and oxygen, irreversible photo-degradation originating from intrinsic defects is still challenging and remains elusive. Herein, the photo-aging mechanism due to intrinsic defects is investigated in nitrogen-filled conditions, excluding extrinsic degradation factors. Devices...

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“…Accordingly, it is possible to find different strategies to improve the lifetime, including the encapsulation process/method, kind of perovskite (2D, 3D, Etc. ), selective charge contacts or other layers involved [29], passivation of the interfaces [30] or the grain boundaries [31]. Nevertheless, because the degradation is a complex process that depends on the structure (layers) and their interfaces, the degradation studies must be conducted in the complete device and not in isolated layers [32].…”

Section: Perovskite Degradationmentioning

confidence: 99%

Outdoor Performance of Perovskite Photovoltaic Technology

Velilla¹,

Quintero²,

Montoya³

et al. 2022

Thin Films Photovoltaics

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In the case of emerging photovoltaic technologies such as perovskite, most published works have focused on laboratory-scale cells, indoor conditions and no international standards have been fully established and adopted. Accordingly, this chapter shows a brief introduction on the standards and evaluation methods for perovskite solar minimodules under natural sunlight conditions. Therefore, we propose evaluating the outdoor performance in terms of power, following the international standard IEC 61853–1 to obtain the performance according to the power rating conditions. After some rigorous experimental evaluations, results shown that the maximum power (Pmax) evolution for the analyzed minimodules could be correlated with one of the three patterns commonly described for degradation processes in the literature, named convex, linear, and concave. These patterns were used to estimate the degradation rate and lifetime (T80). Moreover, ideality factor (nID) was estimated from the open-circuit voltage (Voc) dependence on irradiance and ambient temperature (outdoor data) to provide physical insight into the recombination mechanism dominating the performance during the exposure. In this context, it was observed that the three different degradation patterns identified for Pmax can also be identified by nID. Finally, based on the linear relationship between T80 and the time to first reach nID = 2 (TnID2), is demonstrated that nID analysis could offer important complementary information with important implications for this technology outdoor development, due that the changes in nID could be correlated with the recombination mechanisms and degradation processes occurring in the device.

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Origins of High Performance and Degradation in the Mixed Perovskite Solar Cells

Cited by 45 publications

References 28 publications

Impedance Spectroscopy of Perovskite Solar Cells: Studying the Dynamics of Charge Carriers Before and After Continuous Operation

Impedance Spectroscopy of Perovskite Solar Cells: Studying the Dynamics of Charge Carriers Before and After Continuous Operation

Investigation of Defect‐Tolerant Perovskite Solar Cells with Long‐Term Stability via Controlling the Self‐Doping Effect

Outdoor Performance of Perovskite Photovoltaic Technology

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