A facile approach for fabricating efficient and stable perovskite solar cells.

Perovskite solar cells (PSCs) with high power conversion efficiencies (PCEs) can be produced using a variety of methods, such as different fabrication methods, device layout modification, and component and interface engineering. The efficiency of a perovskite solar cell is largely dependent on the overall quality of the perovskite thin-film in every scenario. The utilization of spin-coating followed by the antisolvent pouring (ASP) method is prevalent in nearly all fabrication techniques to achieve superior perovskite thin-films.

Fabricating Planar Perovskite Solar Cells through a Greener Approach.

High-quality perovskite thin films are typically produced via solvent engineering, which results in efficient perovskite solar cells (PSCs). Nevertheless, the use of hazardous solvents like precursor solvents (N-Methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), gamma-butyrolactone (GBL)) and antisolvents (chlorobenzene (CB), dibutyl ether (DEE), diethyl ether (EtO), etc.) is crucial to the preparation of perovskite solutions and the control of perovskite thin film crystallization.

Learn-and-Match Molecular Cations for Perovskites.

Forecasting the structural stability of hybrid organic/inorganic compounds, where polyatomic molecules replace atoms, is a challenging task; the composition space is vast, and the reference structure for the organic molecules is ambiguously defined. In this work, we use a range of machine-learning algorithms, constructed from state-of-the-art density functional theory data, to conduct a systematic analysis on the likelihood of a given cation to be housed in the perovskite structure. In particular, we consider both ABC chalcogenide (I-V-VI) and halide (I-II-VII) perovskites.

Correction: Exploring new approaches towards the formability of mixed-ion perovskites by DFT and machine learning.

Correction for 'Exploring new approaches towards the formability of mixed-ion perovskites by DFT and machine learning' by Heesoo Park et al., Phys. Chem.

Exploring new approaches towards the formability of mixed-ion perovskites by DFT and machine learning.

Recent years have witnessed a growing effort in engineering and tuning the properties of hybrid halide perovskites as light absorbers. These have led to the successful enhancement of their stability, a feature that is often counterbalanced by a reduction of their power-conversion efficiency. In order to provide a systematic analysis of the structure-property relationships of this class of compounds we have performed density functional theory calculations exploring fully inorganic ABC chalcogenide (I-V-VI), halide (I-II-VII) and hybrid perovskites.

Water-Repellent Low-Dimensional Fluorous Perovskite as Interfacial Coating for 20% Efficient Solar Cells.

Hybrid perovskite solar cells have been capturing an enormous research interest in the energy sector due to their extraordinary performances and ease of fabrication. However, low device lifetime, mainly due to material and device degradation upon water exposure, challenges their near-future commercialization. Here, we synthesized a new fluorous organic cation used as organic spacer to form a low-dimensional perovskite (LDP) with an enhanced water-resistant character.

Elucidating the Impact of Chalcogen Content on the Photovoltaic Properties of Oxychalcogenide Perovkskites: NaMO Q (M=Nb, Ta; Q=S, Se, Te).

In the quest for nontoxic and stable perovskites for solar cells, we have conducted a systematic study of the effect of chalcogen content in oxychalcogenide perovskite by using DFT and quasi-particle perturbation theory. We explored the changes in the electronic structure due to the substitution of O atoms in NaNbO and NaTaO perovskite structures with various chalcogens (S, Se, Te) at different concentrations. Interestingly, the introduction of the chalcogen atoms resulted in a drastic reduction in the electronic band gap, which made some of the compounds fall within the visible range of the solar spectrum.

Approaches for Selective Synthesis of Ullazine Donor-Acceptor Systems.

Methods for effective synthesis for the four possible isomeric 3,9-diphenylullazine carboxaldehydes and reactive halogen intermediates are described. Ullazine donor-acceptor (D-A) dyes were studied using UV/Vis, photoluminescence (PL) spectroscopy and cyclic voltammetry. X-ray single crystal diffraction analysis independently confirmed the structures of two key intermediates.

Full space device optimization for solar cells.

Advances in computational materials have paved a way to design efficient solar cells by identifying the optimal properties of the device layers. Conventionally, the device optimization has been governed by single or double descriptors for an individual layer; mostly the absorbing layer. However, the performance of the device depends collectively on all the properties of the material and the geometry of each layer in the cell.

Femtosecond Charge-Injection Dynamics at Hybrid Perovskite Interfaces.

With a power conversion efficiency (PCE) exceeding 22 %, perovskite solar cells (PSCs) have thrilled photovoltaic research. However, the interface behavior is still not understood and is a hot topic of research: different processes occur over a hierarchy of timescales, from femtoseconds to seconds, which makes perovskite interface physics intriguing. Herein, through femtosecond transient absorption spectroscopy with spectral coverage extending into the crucial IR region, the ultrafast interface-specific processes at standard and newly molecularly engineered perovskite interfaces in state-of-the-art PSCs are interrogated.

Enhancing the carrier thermalization time in organometallic perovskites by halide mixing.

Hybrid metal-organic halide perovskites have recently attracted a great deal of attention because of their interesting electronic, optical and transport properties, which make them promising materials for high-performance, low-cost solar cells. Fundamental understanding of the formation mechanisms and dynamics of photoinduced charge carriers is essential for improving the performance of perovskite solar cell devices. For example, a significant amount of absorbed solar energy is lost as a result of carrier thermalization.

Revealing the role of organic cations in hybrid halide perovskite CH3NH3PbI3.

The hybrid halide perovskite CH3NH3PbI3 has enabled solar cells to reach an efficiency of about 20%, demonstrating a pace for improvements with no precedents in the solar energy arena. Despite such explosive progress, the microscopic origin behind the success of such material is still debated, with the role played by the organic cations in the light-harvesting process remaining unclear. Here van der Waals-corrected density functional theory calculations reveal that the orientation of the organic molecules plays a fundamental role in determining the material electronic properties.