Now showing 1 - 4 of 4
  • Publication
    Revealing Size‐Dependency of Ionic Liquid to Assist Perovskite Film Formation Mechanism for Efficient and Durable Perovskite Solar Cells
    (2023) ;
    Wang, Fei
    ;
    Zhou, Kang
    ;
    Liang, Xiao
    ;
    Zhou, Xianfang
    ;
    Duan, Dawei
    ;
    Ge, Chuangye
    ;
    Zhang, Xintao
    ;
    Shi, Yumeng
    ;
    Lin, Haoran
    ;
    Zhu, Quanyao
    ;
    Hu, Hanlin
    ;
    Zhang, Hongyu
    Ionic liquids (ILs) are extensively utilized for the manipulation of crystallization kinetics of perovskite, morphology optimization, and defect passivation for the fabrication of highly efficient and stable devices. However, comparing ILs with different chemical structures and selecting the appropriate ILs from the many types available to enhance perovskite device performance remains a challenge. In this study, a range of ILs containing different sizes of anions are introduced as additives for assisting in film formation in perovskite photovoltaics. Specifically, ILs with various sizes significantly affects the strength of chemical interaction between ILs and perovskite composition, inducing varying degrees of conversion of lead iodide to perovskite as well as the formation of perovskite films with markedly disparate grain sizes and morphology. Theoretical calculations in conjunction with experimental measurements revealed that small-sized anion can more effectively reduce defect density by filling halide vacancies within perovskite bulk materials, resulting in suppression of charge-carrier recombination, an extended photoluminescence lifetime, and significantly improved device performance. Boosted by ILs with appropriate size, the champion power conversion efficiency of 24.09% for the ILs-treated device is obtained, and the unencapsulated devices retain 89.3% of its original efficiency under ambient conditions for 2000 h.
    Scopus© Citations 2  4
  • Publication
    The Role of Ionic Liquids in Performance Enhancement of Two‐Step Perovskite Photovoltaics
    (2023)
    Liang, Xiao
    ;
    Duan, Dawei
    ;
    Al-Handawi, Marieh B.
    ;
    Wang, Fei
    ;
    Zhou, Xianfang
    ;
    Ge, Chuang-ye
    ;
    Lin, Haoran
    ;
    Quanyao Zhu
    ;
    ;
    Naumov, Panče
    ;
    Hu, Hanlin
    Much of the research efforts of late that are directed toward enhancement of the efficiency of perovskite-based photovoltaics are focused on the application of ionic liquids (ILs) in a one-step approach. On the contrary, the details of the alternative two-step approach, such as the role of the ILs in the perovskite film solidification and its optoelectronic properties, remain poorly understood despite the increasing evidence that this latter method might offer considerable advantages, including better reproducibility and control over crystallization. Herein, the effect of IL methylammonium acetate (MAAc) introduced into the PbI2 layer by a sequential deposition process on the optoelectronic properties of the perovskite film and the performance of the ensuing photovoltaic devices are studied. The addition of MAAc lowers the MAAc–perovskite formation enthalpy, leading to an accelerated solidification process. Moreover, MAAc suppresses the formation of Pb0, thereby facilitating the perovskite formation while lowering the deep defect states caused by Pb0. In addition to grain boundary passivation, the acetate ions can diffuse into the bulk of the perovskite material, filling up the halide vacancies with reduced trap state density. As a result, a decent power conversion efficiency of 23.36% is achieved, with noticeably improved durability.
      16
  • Publication
    Recent Progress in Ionic Liquids for Stability Engineering of Perovskite Solar Cells
    (2022) ;
    Wang, Fei
    ;
    Ge, Chuang-ye
    ;
    Duan, Dawei
    ;
    Lin, Haoran
    ;
    Naumov, Panče
    ;
    Hu, Hanlin
    Perovskite solar cells attract widespread attention due to their impressive power conversion efficiencies, high absorption coefficients, tunable bandgap, and straightforward manufacturing protocols. However, in the process of further development and optimization toward mass production, the long-term stability stands as one of the most urgent challenges that need to be overcome. Given the excellent thermal stability and high structural designability, ionic liquids (ILs) are relatively green room-temperature molten salts that have been widely applied to perovskite photovoltaic devices with promising results in view of improved stability and enhanced device performance. In this review, the reasons and mechanisms of instability of such devices under external and internal factors are analyzed. The current strategies of ILs engineering for improved stability of the devices are classified and summarized, including the IL-assisted perovskite film evolution and IL-modified photophysical properties of the perovskite photoactive layer and the related stability and photovoltaic performance of the devices. The challenges that stand as obstacles toward further development of perovskite solar cells based on IL engineering and their prospects are also discussed.
      17  21
  • Publication
    Ionic Liquid Engineering in Perovskite Photovoltaics
    (2022) ;
    Wang, Fei
    ;
    Duan, Dawei
    ;
    Singh, Mriganka
    ;
    Sutter‐Fella, Carolin M
    ;
    Lin, Haoran
    ;
    Naumov, Panče
    ;
    Hu, Hanlin
    Over the past decade, perovskite photovoltaics have approached other currently available technologies and proven to be the most prospective type of solar cells. Although the many-sided research in this very active field has generated consistent results with regards to their undisputed consistently increasing power conversion efficiency, it also produced several rather contradictory opinions. Among other important details, debate surrounding their proneness to surface degradation and poor mechanical robustness, as well as the environmental footprint of this materials class remains a moot point. The application of ionic liquids appears as one of the potential remedies to some of these challenges due to their high conductivity, the opportunities for chemical ‘tuning’ of the structure, and relatively lower environmental footprint. This article provides an overview, classification, and applications of ionic liquids in perovskite solar cells. We summarize the use and role of ionic liquids as versatile additives, solvents, and modifiers in perovskite precursor solution, charge transport layer, as well as for interfacial and stability engineering. Finally, challenges and the future prospects for the design and/or selection of ionic liquids with a specific profile that meets the requirements for next generation highly efficient and stable perovskite solar cells are proposed.
    Scopus© Citations 1  146  50