Dounya Barrit

• Doctor of Material Science and Engineering
• PV Reliability R&D Engineer at TotalEnergies

The successful and widely used two-step process of producing the hybrid organic-inorganic perovskite CH3NH3PbI3, consists of converting a solution deposited PbI2 film by reacting it with CH3NH3I. Here, we investigate the solidification of PbI2 films from a DMF solution by performing in situ grazing incidence wide angle X-ray scattering (GIWAXS) mea...

Producing high efficiency solar cells without high‐temperature processing or use of additives still remains a challenge with the two‐step process. Here, the solution processing of MAPbI3 from PbI2 films in N,N‐dimethylformamide (DMF) is investigated. In‐situ grazing incidence wide‐angle X‐ray scattering (GIWAXS) measurements reveal a sol–gel proces...

Planar perovskite solar cells can be prepared without high temperature processing steps typically associated with mesoporous device architectures; however, their efficiency has been lower and producing high quality perovskite films in planar devices has been challenging. Here, we report a modified two-step interdiffusion protocol suitable to prepar...

Perovskite solar cells have shown a strong increase in efficiency over the last 15 years. With a record power conversion efficiency on small area above 34%, perovskite/silicon tandem solar cells already exceed the efficiency limit of silicon solar cells and their efficiency is expected to increase further. While predicted to take large markets shar...

This work is a detailed report of the synthesis and characterization of high-quality CH3NH3PbX3(X = I, Br, and Cl) powders as precursor materials for perovskite based optoelectronic devices. MAPbX3 powders were synthesized through easy processing steps with simple precursors. The X-ray diffraction (XRD) analysis revealed that the synthesized materi...

Lead halide perovskites have been of paramount interest for solution-processable solar cells, reaching power conversion efficiencies larger than 25%. In this spotlight, we will provide a systematic overview of the influence of different solution-based processing routes of lead halide perovskites on their phase transformation and conversion as revea...

Perovskite photovoltaic solar cells have gained popularity throughout the past few years. They have become the subject of multiple research studies due to their ability to achieve high efficiencies, specifically all-inorganic perovskite solar cells. They demonstrate a record operational lifetime and are also cheap to manufacture and highly efficien...

Eco-friendly printing is important for mass manufacturing of thin-film photovoltaic (PV) devices to preserve human safety and the environment and to reduce energy consumption and capital expense. However, it is challenging for perovskite PVs due to the lack of eco-friendly solvents for ambient fast printing. In this study, we demonstrate for the fi...

Our current understanding of the crystallization, morphology evolution and phase stability of wide bandgap hybrid perovskite thin films is very limited, as much of the community's focus has been on lower bandgap systems. Here, we investigate the crystallization behavior and film formation of wide and tunable bandgap MAPbBr3‐xClx films and contrast...

Inorganic−organic hybrid perovskites MAPb(IxBr1−x)3 (0 < x < 1) hold promise for efficient multi‐junction or tandem solar cells due to tunable bandgap and improved long‐term stability. However, the phase transformation from Pb(IxBr1−x)2 precursors to perovskites is not fully understood which hinders further improvement of optoelectronic properties...

Perovskite photovoltaics have made extraordinary strides in efficiency and stability thanks to process and formulation developments like anti-solvent dripping and mixed-cation mixed-halide compositions. Solar cell fabrication through low-cost scalable methods, such as blade coating, cannot accommodate anti-solvent dripping and needs to be performed...

Perovskite photovoltaics have made extraordinary progress in power conversion efficiency (PCE) and stability owing to process and formulation development. Perovskite cell performance benefits from the addition of alkali metal cations, such as cesium (Cs⁺) and potassium (K⁺) in mixed ion systems, but the underlying reasons are not fully understood....

As a coating method compatible with printing, one-step spin-coating is widely used for fabricating perovskite thin films. Controlling the crystal growth rate of two precursors is essential to obtain a homogeneous film morphology. However, the film formation mechanism and role of solvate systems during spin-coating have not yet been clearly revealed...

The two‐step conversion process consisting of metal halide deposition followed by conversion to hybrid perovskite has been successfully applied toward producing high‐quality solar cells of the archetypal MAPbI3 hybrid perovskite, but the conversion of other halide perovskites, such as the lower bandgap FAPbI3, is more challenging and tends to be ha...

Perovskite photovoltaics have made extraordinary strides in efficiency and stability thanks to process and formulation developments like the anti-solvent drip and mixed-cation mixed-halide compositions. Solar cell fabrication through low-cost scalable...

The role of residual lead iodide on the photophysical properties of methylammonium lead iodide is still unclear and contradictory views exists about its impact. Herein, we report that there is a critical amount of residual lead iodide, which is beneficial for the solar cell performance. We employed transient absorption spectroscopy to investigate t...

Perovskite solar cells have garnered significant interest thanks to the impressive rise of their efficiency over the last few years to a power conversion efficiency (PCE) of 25.2% despite being processable using cheap and potentially high-throughput solution coating techniques. Using the two-step conversion process high-quality perovskite films wit...

Perovskite solar cells based on two-dimensional/three-dimensional (2D/3D) hierarchical structure have attracted significant attention in recent years due to their promising photovoltaic performance and stability. But to obtain a detailed understanding of interfacial mechanism at the 2D/3D heterojunction, e.g. the ligand-chemistry dependent nature o...

All-inorganic halide perovskites hold promise for emerging thin-film photovoltaics due to their excellent thermal stability. Unfortunately, it has been challenging to achieve high-quality films over large areas using scalable methods under realistic ambient conditions. Herein, we investigated the coupling between the fluid dynamics and the structur...

Perovskite solar cells increasingly feature mixed‐halide mixed‐cation compounds (FA1−x−yMAxCsyPbI3−zBrz) as photovoltaic absorbers, as they enable easier processing and improved stability. Here, the underlying reasons for ease of processing are revealed. It is found that halide and cation engineering leads to a systematic widening of the anti‐solve...

With record power conversion efficiencies (PCE) close to 24%, perovskite solar cells (PSCs) hold great promise to combine high photovoltaic performance with low processing cost. [1-4] This combination can be ascribed to several factors, such as the remarkable optoelectronic properties of perovskites-evidenced by a sharp absorption onset, a small Ur...

Inherent phase segregation occurs during the pristine film crystallization, resulting in non-uniform halide and cation compositions, including MA-I-rich ordered solvates and FA-Br-rich 6H phase. Addition of Cs + and Rb + jointly conducts the perovskite orchestra: they synergistically promote the crystallization of a single 3C perovskite phase with...

Mixed lead halide perovskite solar cells have been demonstrated to benefit tremendously from the addition of Cs+ and Rb+, but its root cause is yet to be understood. This hinders further improvement, and processing approaches remain largely empirical. We address the challenge by tracking the solidification of precursors in situ and linking the evol...

Organic–inorganic lead‐based halide perovskite compounds currently yield thin film solar cells with a power conversion efficiency (PCE) of >23%. However, replacing the lead with less‐toxic elements while maintaining a high PCE remains a challenge. For this reason, there has been significant effort to develop Pb‐free compounds, including methylammon...

Producing high efficiency solar cells without high-temperature processing or use of additives still remains a challenge with the two-step process. Here, the solution processing of MAPbI 3 from PbI 2 films in N,N-dimethylformamide (DMF) is investigated. In-situ grazing incidence wide-angle X-ray scattering (GIWAXS) measurements reveal a sol-gel proc...

Ambient stability remains a critical hurdle for commercialization of perovskite solar cells. Two-dimensional Ruddlesden-Popper (RP) perovskite solar cells exhibit excellent stability but suffer from low photovoltaic performance so far. Herein, RP/3D heterostructure passivated by semiconducting molecules is reported, which systematically addresses b...

Hybrid organic metal halide perovskite solar cells have now reached power conversion efficiencies (PCE) of more than 22%. To date, the highest device efficiencies for perovskite solar cells have been demonstrated for mesoporous charge transport layers, which require a high temperature (≥ 500 °C) annealing step. In contrast, the planar device archit...

Perovskite solar cells have garnered significant interest thanks to the meteoric rise of their efficiency over the last few years to a power conversion efficiency (PCE) of 22.1% despite being processable using cheap and potentially high-throughput solution coating techniques. Currently, the two-step process employed to produce hybrid organic-inorga...

The successful and widely used two-step process of producing the hybrid organic-inorganic perovskite CH3NH3PbI3, consists of converting a solution deposited PbI2 film by reacting it with CH3NH3I. Here, we investigate the solidification of PbI2 films from a DMF solution by performing in situ grazing incidence wide angle X-ray scattering (GIWAXS) mea...

Organometallic halide perovskite solar cells have reached power conversion efficiencies (PCE) of more than 21%, yet only when a mesoporous electrode structure is used. These mesoporous charge transport layers require a high temperature (≥ 500 °C) annealing step during device fabrication. In contrast, the planar device architecture is more practical...

Hybrid perovskite solar cells have emerged as a remarkable contender for low-cost fabrication of highly efficient solar cells and modules. Current record efficiency cells with power conversion efficiency exceeding 22% are fabricated using the well-established solution-based two-step method, which consists in deposition of PbI2 and its subsequent co...

This work consists on the improvement of first surface silvered thick glass mirrors. Several types of CSP mirrors based on different Physical Vapor Deposition techniques (PVD) and the presence or absence of the copper protective back layer were prepared: ([Ag Sputtered], [Ag Evaporated], [Cu Sputtered-Ag Evaporated], [Cu Evaporated-Ag Sputtered], [...

The main focus of this research project is the improvement of the quality of concentrated solar power plants by developing new coating materials that are lighter, more durable, energy efficient and more cost-effective; and consequently reducing the need for maintenance while improving the mirrors’ efficiency by application of special coating on the...

Many race cars were built as universities' and high schools' projects; however, the concept of solar cars have not been developed for consumers more often. RALOS project is about designing and building a theoretical model of a hybrid car using the best features while making the most optimal design decisions by evaluation the best existing cars' tec...