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Sally Mabrouk

Bio: Sally Mabrouk is an academic researcher from South Dakota State University. The author has contributed to research in topics: Perovskite (structure) & Materials science. The author has an hindex of 13, co-authored 17 publications receiving 747 citations.

Papers
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TL;DR: In this paper, a review focusing on various perovskite formation and crystallization routes with respect to processing parameters including the precursor solvent, solvent mixture, temperature, time, formation of solvent led intermediate complex species, doping and humidity are discussed.
Abstract: An organic–inorganic perovskite is comprised of an organic cation (CH3NH3+, FAI, or Cs), a metal cation (Pb2+ or Sn2+) and a halide (I−, Cl−, or Br−) molecule. Precursor salts containing these cations, molecules and halide ions dissolved in solvents are used to prepare perovskite films. Perovskite film formation takes place through the reaction of precursor elements, which is assisted by various processing conditions such as thermal annealing, moisture and solvent treatment. This review focuses on various perovskite formation and crystallization routes with respect to processing parameters including the precursor solvent, solvent mixture, temperature, time, formation of solvent led-intermediate complex species, doping and humidity. Adding water as the dopant to the precursor solvent and exposure to moisture from atmospheric humidity to improve perovskite film quality are also discussed. Processing conditions and crystallization processes are described in correlation with the perovskite film morphology, crystallinity, defects, charge transport and device performance. This article will aim to highlighting recent findings in the selection of solvents in the crystallization of perovskite films, solvent induced intermediate phases, and effects of water in assisting perovskite crystallization for improved film quality and device performance. The review will also present various structural and nanoscale characterization techniques that have been used to probe solvent based intermediate species transformation processes to the perovskite phase and understand the effects in correlation with device performance.

180 citations

Journal ArticleDOI
TL;DR: In this paper, two new hole transport materials (HTMs), H16 and H18, have been obtained through a facile synthetic route by cross linking triarylamine-based donor groups with a 4-(4-methoxyphenyl)-4H-dithieno[3,2-b:2′,3′-d]pyrrole (MPDTP) and N-(4-(4H]-pyrrol-4-yl)phenyl)-N-(4methoxy-N-( 4-mETHoxyp
Abstract: Dithieno[3,2-b:2′,3′-d]pyrrole (DTP) derivatives are one of the most important organic photovoltaic materials due to better π-conjugation across fused thiophene rings. In this work, two new hole transport materials (HTMs), H16 and H18, have been obtained through a facile synthetic route by cross linking triarylamine-based donor groups with a 4-(4-methoxyphenyl)-4H-dithieno[3,2-b:2′,3′-d]pyrrole (MPDTP) and N-(4-(4H-dithieno[3,2 b:2′,3′-d]pyrrol-4-yl)phenyl)-4-methoxy-N-(4-methoxyphenyl)aniline (TPDTP) unit, respectively. The H16 HTM outperforms the H18 in terms of conductivity, hole mobility, and hole transport at the interface. This result could be attributed to the enhancement of the conductivity, hole mobility and high quality of the film exerted by the MPDTP core. The optimized device based on H16 exhibits a high power conversion efficiency (PCE) of 18.16%, which is comparable to that obtained with the state-of-the-art-HTM spiro-OMeTAD (18.27%). Furthermore, the long-term aging test shows that the H16 based device has good stability after two months of aging under controlled (20%) humidity in the dark. Importantly, the synthesis cost of H16 is roughly 1/5 of that of spiro-OMeTAD. The present finding highlights the potential of DTP based HTMs for efficient PSCs.

112 citations

Journal ArticleDOI
TL;DR: Transient photocurrent and photovoltage measurements show the shortest charge transport time at 0.99 μs and the longest charge carrier life time at 13.6 μs for perovskite films prepared from 5% water in MAI solution, which improved perovSkite solar cell efficiency from 9.04% to 12.42%.
Abstract: An optimal small amount of water added into methyl ammonium iodide (MAI) solution in isopropyl alcohol (IPA) helps perovskite crystallization and leads to larger grain size from sequential deposition of perovskite films. The concentration of water was varied from 1% to 7% (vol% of IPA) in MAI solution and optical absorption, crystallization, morphology of perovskite films and their photovoltaic performance were studied in perovskite solar cells. 5% by volume was found to lead to preferential crystallization in the (110) plane with grain size about three times that of perovskite films prepared without adding water into the MAI solution. The optimal water concentration of 5% by volume in the MAI solution led to average perovskite grain size of ∼600 nm and solar cell efficiency of 12.42% at forward scan with a rate of 0.5 V s(-1). Device performance decreases after increasing water concentration beyond 5% in the MAI solution due to formation of the PbI2 phase. Transient photocurrent and photovoltage measurements show the shortest charge transport time at 0.99 μs and the longest charge carrier life time at 13.6 μs for perovskite films prepared from 5% water in MAI solution, which improved perovskite solar cell efficiency from 9.04% to 12.42%.

97 citations


Cited by
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Journal ArticleDOI
TL;DR: The fundamentals, recent research progress, present status, and views on future prospects of perovskite-based photovoltaics, with discussions focused on strategies to improve both intrinsic and extrinsic (environmental) stabilities of high-efficiency devices are described.
Abstract: The photovoltaics of organic–inorganic lead halide perovskite materials have shown rapid improvements in solar cell performance, surpassing the top efficiency of semiconductor compounds such as CdTe and CIGS (copper indium gallium selenide) used in solar cells in just about a decade. Perovskite preparation via simple and inexpensive solution processes demonstrates the immense potential of this thin-film solar cell technology to become a low-cost alternative to the presently commercially available photovoltaic technologies. Significant developments in almost all aspects of perovskite solar cells and discoveries of some fascinating properties of such hybrid perovskites have been made recently. This Review describes the fundamentals, recent research progress, present status, and our views on future prospects of perovskite-based photovoltaics, with discussions focused on strategies to improve both intrinsic and extrinsic (environmental) stabilities of high-efficiency devices. Strategies and challenges regardi...

1,720 citations

Journal ArticleDOI
08 Nov 2019-Science
TL;DR: Doping of formamidinium lead iodide with methylenediammonium dichloride maintains the band gap of the active α-phase of the FAPbI3 phase and achieves a certified short-circuit current density of between 26.1 and 26.7 milliamperes per square centimeter.
Abstract: In general, mixed cations and anions containing formamidinium (FA), methylammonium (MA), caesium, iodine, and bromine ions are used to stabilize the black α-phase of the FA-based lead triiodide (FAPbI3) in perovskite solar cells. However, additives such as MA, caesium, and bromine widen its bandgap and reduce the thermal stability. We stabilized the α-FAPbI3 phase by doping with methylenediammonium dichloride (MDACl2) and achieved a certified short-circuit current density of between 26.1 and 26.7 milliamperes per square centimeter. With certified power conversion efficiencies (PCEs) of 23.7%, more than 90% of the initial efficiency was maintained after 600 hours of operation with maximum power point tracking under full sunlight illumination in ambient conditions including ultraviolet light. Unencapsulated devices retained more than 90% of their initial PCE even after annealing for 20 hours at 150°C in air and exhibited superior thermal and humidity stability over a control device in which FAPbI3 was stabilized by MAPbBr3.

823 citations

Journal ArticleDOI
TL;DR: In this paper, the authors provide guidelines on successfully choosing spacers and incorporating them into crystalline materials and optoelectronic devices and provide a summary of various synthetic methods to act as a tutorial for groups interested in pursuing synthesis of novel 2D halide perovskites.
Abstract: Two-dimensional (2D) halide perovskites have emerged as outstanding semiconducting materials thanks to their superior stability and structural diversity. However, the ever-growing field of optoelectronic device research using 2D perovskites requires systematic understanding of the effects of the spacer on the structure, properties, and device performance. So far, many studies are based on trial-and-error tests of random spacers with limited ability to predict the resulting structure of these synthetic experiments, hindering the discovery of novel 2D materials to be incorporated into high-performance devices. In this review, we provide guidelines on successfully choosing spacers and incorporating them into crystalline materials and optoelectronic devices. We first provide a summary of various synthetic methods to act as a tutorial for groups interested in pursuing synthesis of novel 2D perovskites. Second, we provide our insights on what kind of spacer cations can stabilize 2D perovskites followed by an extensive review of the spacer cations, which have been shown to stabilize 2D perovskites with an emphasis on the effects of the spacer on the structure and optical properties. Next, we provide a similar explanation for the methods used to fabricate films and their desired properties. Like the synthesis section, we will then focus on various spacers that have been used in devices and how they influence the film structure and device performance. With a comprehensive understanding of these effects, a rational selection of novel spacers can be made, accelerating this already exciting field.

343 citations

Journal ArticleDOI
TL;DR: In this paper, several techniques related to the synthesis of ZnO nanostructures and their efficient performance in sensing are reviewed, such as functionalization of noble metal nanoparticles, doping of metals, inclusion of carbonaceous nanomaterials, using nanocomposites of different MO x, UV activation, and post-treatment method of high-energy irradiation on ZnOs, with their possible sensing mechanisms.

323 citations

Journal ArticleDOI
TL;DR: A comprehensive review on the effect of water on the state-of-the-art lead-based perovskite solar cells is provided in this paper, where it is shown that a moderate amount of water can facilitate nucleation and crystallization of the perovsite material, resulting in better perov-skite film quality and enhanced PSC performance.
Abstract: The performance and stability of organic–inorganic hybrid perovskite solar cells (PSCs) is sensitive to water and moisture in an ambient environment. Understanding how H2O influences the perovskite material is also important for developing appropriate control strategies to mitigate the problem. Here we provide a comprehensive review on the effect of water on the state-of-the-art lead-based perovskite solar cells in terms of perovskite material design, perovskite film preparation, device fabrication, and photovoltaic application. It is found that a moderate amount of water can facilitate nucleation and crystallization of the perovskite material, resulting in better perovskite film quality and enhanced PSC performance. The perovskite materials are irreversibly destroyed by H2O after a certain level of water, but they exihibit better tolerance than initially expected. Humidity resistant fabrication of high-performance PSC devices and modules should therefore be favoured. Generally, water shows a negative effect on the long-term stability and lifetime of PSCs. To reduce the effects from water during outdoor operation, attention should be paid to different protection methods such as varying the perovskite composition, optimizing the electron/hole transport layer and encapsulation of the device.

310 citations