Retardation of Trap‐Assisted Recombination in Lead Halide Perovskite Solar Cells by a Dimethylbiguanide Anchor Layer

Xue, Baoda; Bi, Shiqing; You, Shuai; Zhou, Jianhui; Wu, Guo Qing; Meng, Rui; Wang, Boxin; Wang, Jianqiu; Leng, Xuanye; Zhang, Yuan; Ma, Xiangdong; Zhou, Huiqiong

doi:10.1002/chem.201804799

Cited by 10 publications

(7 citation statements)

References 42 publications

(67 reference statements)

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“…Notably, the peaks representing C═N and C─N bonds showed diminished intensities, and that of N-H was weak, implying hydrogen bonding between residual hexane and FA þ . [51] The increased (110)/(220) ratio in the XRD pattern of the Hex-treated perovskite film corroborated this result (Figure 6a), which indicates that the hexane-FA þ hydrogen bonding affected the crystallinity of the perovskite. In the case of the EtOH-treated perovskite film (Figure 4b), stretch bending appeared at 1707.5, 1607, and 1352 cm À1 , and, in particular, the C¼N peak exhibited a shift.…”

Section: Resultssupporting

confidence: 63%

Optimal Solvents for Interfacial Solution Engineering of Perovskite Solar Cells

et al. 2022

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Interfacial engineering is extensively used to reduce the interfacial loss caused by surface recombination, improve the crystallinity of the active absorption layer, and enhance the long‐term stability of perovskite solar cells (PSCs). Solution processing techniques, such as spin coating and dip coating, are commonly used to deposit the interfacial layer because of their cost‐effectiveness and simplicity. Although determining suitable solutes for use in these processes is important, selecting appropriate solvents is also crucial. Herein, commonly used solvents are investigated to determine optimal solvents for solution processing by categorizing them into nonpolar and polar groups. The results suggest that the efficiency of the PSCs can be increased by simple solvent treatment. In particular, the efficiencies of systems subjected to hexane (nonpolar) and ethanol (polar) treatment are significantly improved (17.31% and 17.44%, respectively) compared with that of a control device (16.24%). Herein, the effects of pure solvents on the SnO2–perovskite interface are confirmed and an important direction for investigations that adopt solution processing to improve the efficiency of PSCs, such as research on interlayers and self‐assembled monolayers, is suggested.

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Section: Resultssupporting

confidence: 63%

Optimal Solvents for Interfacial Solution Engineering of Perovskite Solar Cells

et al. 2022

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“…The process of interfacial charge extraction in PSCs has been shown to heavily rely on the surface conditions of perovskites where surface traps play a critical role. [ 37–39 ] To further understand the mechanisms for the modified CE at low T , we determined the density of states of traps ( t DOS ) in solar cells at different T by admittance spectroscopy, which is a powerful technique to characterize shallow and deep defects in PSCs [ 40,41 ] or organic solar cells. [ 42 ] Details of the derivation on t DOS can be found in SI.…”

Section: Resultsmentioning

confidence: 99%

Understanding Temperature‐Dependent Charge Extraction and Trapping in Perovskite Solar Cells

Zhou

Wang

Meng

et al. 2020

Adv Funct Materials

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Understanding the factors that limit the performance of perovskite solar cells (PSCs) can be enriched by detailed temperature (T)-dependent studies. Based on p-i-n type PSCs with prototype methylammonium lead triiodide (MAPbI 3 ) perovskite absorbers, T-dependent photovoltaic properties are explored and negative T-coefficients for the three device parameters (V OC , J SC , and FF) are observed within a wide low T-range, leading to a maximum power conversion efficiency (PCE) of 21.4% with an impressive fill factor (FF) approaching 82% at 220 K. These T-behaviors are explained by the enhanced interfacial charge transfer, reduced charge trapping with suppressed nonradiative recombination and narrowed optical bandgap at lower T. By comparing the T-dependent device behaviors based on MAPbI 3 devices containing a PASP passivation layer, enhanced PCE at room temperature is observed but different tendencies showing attenuating T-dependencies of J SC and FF, which eventually leads to nearly T-invariable PCEs. These results indicate that charge extraction with the utilized all-organic charge transporting layers is not a limiting factor for low-T device operation, meanwhile the trap passivation layer of choice can play a role in the T-dependent photovoltaic properties and thus needs to be considered for PSCs operating in a temperature-variable environment.

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“…Furthermore, much better thermal and moisture stability were demonstrated from the unencapsulated device with ImAcHCl-modified SnO 2 . A small molecule guanidinium salt, dimethylbiguanide (DMBG), was suggested to be a bifunctional interface passivator at the TiO 2 /perovskite interface . In addition, a biopolymer heparin sodium (HS) was developed to enable trap passivation and retardation on device degradation .…”

mentioning

confidence: 99%

“…A small molecule guanidinium salt, dimethylbiguanide (DMBG), was suggested to be a bifunctional interface passivator at the TiO 2 /perovskite interface. 241 In addition, a biopolymer heparin sodium (HS) was developed to enable trap passivation and retardation on device degradation. 206 COO − and SO 3 − in HS were proposed to be capable of passivating under-coordinated Pb 2+ , while Na + in HS passivated under-coordinated I − , PbI 3 − antisites and/or V I .…”

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confidence: 99%

Materials and Methods for Interface Engineering toward Stable and Efficient Perovskite Solar Cells

2020

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Because interfacial nonradiative recombination (NRR) has a significant influence on device performance, the minimization of interfacial NRR losses through interface engineering especially for perovskite-related interfaces is key to achieving efficient, stable, and hysteresis-free perovskite solar cells (PSCs). In light of important contributions of interface engineering to rapid development of PSCs, a systematic investigation and analysis on the latest research advancements on interface engineering is urgently needed. This Review aims at providing innovative insights into further improvement in power conversion efficiency (PCE) toward the Shockley–Queisser limit efficiency and stability fulfilling commercially available standard protocols as well as reduction of hysteresis. In this Review, the roles and importance of interfaces in PSCs are first highlighted from the viewpoint of device structure, working principles, and interfacial carrier dynamics. The main origins (i.e., interface defects, imperfect energy level alignment (ELA), and interfacial reactions) of interfacial NRR are then discussed in detail along with characterization techniques. Subsequently, the effects of interfacial NRR on PCE, stability, and hysteresis are investigated. Strategies for mitigating interfacial NRR are provided in terms of defect passivation, ELA modulation, and suppression of interfacial reaction, where the critical roles of functional groups of interface modifiers are emphasized. Finally, we provide an outlook for efficient, hysteresis-free, and long-term operationally stable PSCs achievable via interface engineering.

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Retardation of Trap‐Assisted Recombination in Lead Halide Perovskite Solar Cells by a Dimethylbiguanide Anchor Layer

Cited by 10 publications

References 42 publications

Optimal Solvents for Interfacial Solution Engineering of Perovskite Solar Cells

Optimal Solvents for Interfacial Solution Engineering of Perovskite Solar Cells

Understanding Temperature‐Dependent Charge Extraction and Trapping in Perovskite Solar Cells

Materials and Methods for Interface Engineering toward Stable and Efficient Perovskite Solar Cells

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