Experimental study on travelling and standing pattern formation and capillary waves in a pinned liquid film: effects of multi-axis lateral (horizontal) vibrations and substrate geometry

Khan, T.; Eslamian, Morteza

doi:10.1017/jfm.2020.468

Cited by 3 publications

(1 citation statement)

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“…Since 2009 when Miyasaka and co-workers [1] first applied MHP to solar Relevant theoretical studies on waves and vibration imposed on liquids are traced back to 1837 by Faraday. [30] The theory of thin liquid film evolution induced by vibration was gradually established by Kumar and Matar, [31,32] Matar et al, [33] Shklyaev et al, [34,35] Bestehorn, [36] Khan and Eslamian, [37] etc. Ultrasonic vibration has been imposed on perovskite thin films to obtain enhanced solar cell PCE.…”

Section: Introductionmentioning

confidence: 99%

Boosted Charge‐Carrier Transport in Triple‐Cation Perovskites by Ultrasonic Vibration Post Treatment

Wang

Ahmadian‐Yazdi

et al. 2022

Adv Elect Materials

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cells and realized a power conversion efficiency (PCE) of 3.8%, rapid improvements in PCE (currently up to 25.5% [2] ) have been achieved. Because of the tunable optical and electronic properties of MHPs combined with facile processing procedures, [3] applications of MHPs are no longer limited to solar cells, but have quickly extended to light-emitting diodes, [4,5] photodetectors, [6][7][8][9] amplified spontaneous emission of lasers, [10][11][12][13] fieldeffect transistors, [14,15] etc. Among all possible combinations in the category of perovskite materials, triplecation perovskites, consisting of cesium (Cs + ), methylammonium (MA + ), and formamidinium (FA + ) cations at A-site in the ABX 3 structure, have gained tremendous attention. Saliba et al. [16] demonstrated that triple-cation perovskites show outstanding stability in photovoltaic devices and reproducibility during the fabrication process. By introducing a small amount of Cs + in MHPs, unstable yellow phase is effectively suppressed, [16] allowing the formation of a more stable black perovskite phase, which resists against humidity and temperature. The performance of solar cells employing the triple-cation perovskites has improved rapidly in the last 5 years. [17][18][19][20] Zhou and co-workers [20] have obtained an outstanding PCE of 21.46% by simultaneously passivating both anion and cation vacancies in the perovskite layer, and the device preserves 90% of the original PCE after 1000 h of operation. Recently, tandem devices combining triple-cation perovskites and c-Si have reached a PCE of >25%. [21] To fabricate solar cells with desirable performance, it is of vital importance to make high-quality perovskite films by controlling the crystallization process. By doing so, the nonradiative recombination is suppressed. Such positive effects have been reported by Gao et al. in the relevant morphology studies on porphyrin-based organic photovoltaics. [22,23] In this regard, multiple strategies have been developed. The traditional methods to control crystallization require a final step by annealing and drying the liquid films at temperatures ranging from 70 to 150 °C, to form a solid film. [24][25][26][27][28] Despite the simplicity of this method, annealing tends to yield films with rough surface and pores, and defects in the crystalline structure. [29] An alternative approach is to partially or fully replace annealing with ultrasonic vibration with nanoscale amplitudes imposed on the thin liquid films during drying.Ultrasonic vibration imposed on the substrate of a drying perovskite solution film has previously been proposed as a nearly annealing-free method to improve film quality and thus the photovoltaic performance for perovskite solar cells. However, an in-depth understanding of the underlying mechanism of the improved film quality via ultrasonic vibration is still lacking. In this work, the effects of substrate vibration post treatment on the carrier lifetime and mobility are studied in triple-cation perovskite films. With 80 s of annealing-free...

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Section: Introductionmentioning

confidence: 99%

Boosted Charge‐Carrier Transport in Triple‐Cation Perovskites by Ultrasonic Vibration Post Treatment

Wang

Ahmadian‐Yazdi

et al. 2022

Adv Elect Materials

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Droplet impact on a wavy liquid film under multi-axis lateral vibrations

2020

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Impact dynamics of non-spherical droplets on a thin water film

Khan,

Jin,

Yang

2024

Physics of Fluids

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A droplet impinging on a liquid film finds numerous applications in diverse scientific fields. Although studies have primarily focused on spherical droplets, a droplet can present both spherical shape and non-spherical shape at the moment of impact. In the present study, the impact dynamics of a non-spherical droplet on a thin liquid film is investigated experimentally. The results show that, under the same film thickness and Weber number conditions, the splashing and deposition regimes are different for different droplet shapes such as prolate, sphere, and oblate. It is found that the splashing threshold (Ksp) is changed according to the shape of the droplet. Under the same condition when a spherical droplet is in the deposition mode, an oblate droplet is more likely to splash and form secondary droplets, while a prolate droplet is more splash-resistant even at higher Weber numbers. A modified theoretical model for crown radius evolution is developed. The predictions of theoretical model are found to agree well with the experimental results for spherical and non-spherical droplets. Moreover, at the same Weber number, a prolate droplet has a relatively higher maximum crown height than those of an oblate droplet and a spherical droplet.

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Experimental study on travelling and standing pattern formation and capillary waves in a pinned liquid film: effects of multi-axis lateral (horizontal) vibrations and substrate geometry

Abstract: Abstract

Cited by 3 publications

References 46 publications

Boosted Charge‐Carrier Transport in Triple‐Cation Perovskites by Ultrasonic Vibration Post Treatment

Boosted Charge‐Carrier Transport in Triple‐Cation Perovskites by Ultrasonic Vibration Post Treatment

Droplet impact on a wavy liquid film under multi-axis lateral vibrations

Impact dynamics of non-spherical droplets on a thin water film

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