Lasing in Two-Dimensional Tin Perovskites

Two-dimensional (2D) perovskites have been proposed as materials capable of improving the stability and surpassing the radiative recombination efficiency of three-dimensional perovskites. However, their luminescent properties have often fallen short of what has been expected. In fact, despite attracting considerable attention for photonic applications during the last two decades, lasing in 2D perovskites remains unclear and under debate. Here, we were able to improve the optical gain properties of 2D perovskite and achieve optically pumped lasing. We show that the choice of the spacer cation affects the defectivity and photostability of the perovskite, which in turn influences its optical gain. Based on our synthetic strategy, we obtain PEA2SnI4 films with high crystallinity and favorable optical properties, resulting in amplified spontaneous emission (ASE) with a low threshold (30 μJ/cm2), a high optical gain above 4000 cm-1 at 77 K, and ASE operation up to room temperature

Recent progress, fabrication challenges and stability issues of lead-free tin-based perovskite thin films in the field of photovoltaics

Lead-halide perovskite materials have fascinated incredible attention among the research communities due to their favorable electrical and optical properties for optoelectronics and photovoltaic application such as significant light absorption coefficient, higher values of diffusion length, carrier mobility, carrier lifetime, etc. However, lead toxicity as well as its low material stability makes it still far from commercialization. Finding of lead ion replacement is therefore needed to form environmental friendly perovskite materials that are called lead-free perovskites. Among different substitutions, tin is the most potential candidate that is also non-toxic. In this review, the recent development of tin-based lead-free perovskite thin films in photovoltaics research area during the period 2014 till now is summarized. Moreover, the technical challenges and the stability issues faced by them are also discussed. Further, it is suggested that more efforts are needed for the advancement of tin-based lead-free perovskite thin films based solar cells to bring up this field as a cost competent technology for long term sustainability

Tin Halide Perovskites:From Fundamental Properties to Solar Cells

Metal halide perovskites have unique optical and electrical properties, which make them an excellent class of materials for a broad spectrum of optoelectronic applications. However, it is with photovoltaic devices that this class of materials has reached the apotheosis of popularity. High power conversion efficiencies are achieved with lead-based compounds, which are toxic to the environment. Tin-based perovskites are the most promising alternative because of their bandgap close to the optimal value for photovoltaic applications, the strong optical absorption, and good charge carrier mobilities. Nevertheless, the low defect tolerance, the fast crystallization, and the oxidative instability of tin halide perovskites currently limit their efficiency. The aim of this review is to give a detailed overview of the crystallographic, photophysical, and optoelectronic properties of tin-based perovskite compounds in their multiple forms from 3D to low-dimensional structures. At the end, recent progress in tin-based perovskite solar cells are reviewed, mainly focusing on the detail of the strategies adopted to improve the device performances. For each subtopic, the current challenges and the outlook are discussed, with the aim to stimulate the community to address the most important issues in a concerted manner

Lead-Free Perovskite Nanocomposites: An Aspect for Environmental Application

Perovskites possess an interesting crystal structure and its structural properties allow us to achieve various applications. Beside its ferroelectric, piezoelectric, magnetic, multiferroic, etc., properties, these branches of materials are also useful to develop materials for various environmental applications. As the population is increasing nowadays, different type of environmental pollution is one of the growing worries for society. The effort of researchers and scientists focuses on developing new materials to get rid of these individual issues. With modern advances in synthesis methods, including the preparation of perovskite nanocomposites, there is a growing interest in perovskite-type materials for environmental application. Basically, this chapter concludes with a few of the major issues in the recent environment: green energy (solar cell), fuel cell, sensors (gas and for biomedical), and remediation of heavy metals from industrial wastewater

Pure tin halide perovskite solar cells : focusing on preparation and strategies

Metal halide perovskite solar cells (PSCs) have emerged as an important direction for photovoltaic research. Although the power conversion efficiency (PCE) of lead‐based PSCs has reached 25.7%, still the toxicity of Pb remains one main obstacle for commercial adoption. Thus, to address this issue, Pb‐free perovskites have been proposed. Among them, tin‐based perovskites have emerged as promising candidates. Unfortunately, the fast oxidation of Sn2+ to Sn4+ leads to low stability and efficiency. Many strategies have been implemented to address these challenges in Sn‐based PSCs. This work introduces stability and efficiency improvement strategies for pure Sn‐based PSCs by optimization of the crystal structure, processing and interfaces as well as, implementation of low‐dimension structures. Finally, new perspectives for further developing Sn‐based PSCs are provided.Henan Province college youth backbone teacher projectProperPhotoMileSpanish Ministry of Science and EducationFederal Ministry for Economic Affairs and EnergyNational Natural Science Foundation of ChinaDeutsche ForschungsgemeinschaftIsrael Ministry of EnergyHorizon 2020 Framework ProgrammeProjekt DEA

Structures and properties of alkali metal hybrid halide perovskites containing dabconium or piperazinium

Dissertation (MSc (Chemistry))--University of Pretoria, 2021.Hybrid halide perovskites have received much attention over the past two decades due to their realisation in optoelectronic applications. In this study, hybrid halide alkali metal perovskites that contained either piperazinium (piperazine-1,4-diium) or dabconium (1,4-diazabicyclo[2.2.2]octane-1,4-diium) were studied crystallographically and subsequently, their optical band gaps and solid-state fluorescence properties were measured. Specifically, the alkali metal halides NaCl, NaBr, NaI, KCl, KBr, KI, CsCl, CsBr and CsI were employed in combination with the aforementioned organic dications. Moreover, diffuse reflectance spectroscopy was used to measure the optical band gaps of the materials. Sixteen perovskite structures were determined, nine of which are novel. Eight novel dabconium-containing perovskite structures and one piperazinium-containing structure were obtained. The dabconium-series exhibited one of two structural dimensionalities, either a 3D perovskite structure (six in total) or a 1D ABX3-type perovskite structure (five in total). Similarly, the piperazinium-series also exhibited either a 3D structure (four in total) or a 1D ⟨100⟩-type perovskite structure (one structure). In addition, the piperazinium-series was found to generally crystallise with water molecules included in the crystal structure, whereas the dabconium-series did not. The dabconium-containing structures crystallised in a wide range of phases, including monoclinic, orthorhombic, trigonal, and hexagonal phases, while the piperazinium-containing structures were obtained in one of two phases (3D structures in the orthorhombic phase and the 1D structure in the monoclinic phase). Structural trends were identified in both families. The band gaps of the materials from both series were determined to exceed 3.00 eV and hence the materials are unsuited for application as sensitisers in perovskite solar cells. The materials could be classified as either semi-conductors (band gap below 5.0 eV) or insulators (band gap exceeding 5.0 eV). Subsequently, their solid-state fluorescence spectra were measured, and it was determined that none of the perovskite materials obtained in this study exhibited fluorescence at room temperature. However, because of their wide band gap, they may find application in white-light emission devices, such as perovskite light-emitting diodes. Furthermore, though the materials were not suitable as sensitisers in perovskite solar cells, they show promise for application as electron transmitting materials and hence may still be considered in the domain of perovskite solar cells. Notably, structural and property tuneability was illustrated for a specific example of the dabconium-series. It was shown that the material's structure and band gap could be engineered by careful consideration of the precursor constituents, based on the structural trends identified. This tuneability of materials is much desired in the field of materials science. Finally, several avenues for future work, including synthetic extensions, additional property measurements and other potential optoelectronic applications, were identified form the results of this study and show that the perovskite family tree is still revealing new blossoms each day.National Research Foundation of South AfricaChemistryMSc (Chemistry)Unrestricte

Roadmap on organic inorganic hybrid perovskite semiconductors and devices

Metal halide perovskites are the first solution processed semiconductors that can compete in their functionality with conventional semiconductors, such as silicon. Over the past several years, perovskite semiconductors have reported breakthroughs in various optoelectronic devices, such as solar cells, photodetectors, light emitting and memory devices, and so on. Until now, perovskite semiconductors face challenges regarding their stability, reproducibility, and toxicity. In this Roadmap, we combine the expertise of chemistry, physics, and device engineering from leading experts in the perovskite research community to focus on the fundamental material properties, the fabrication methods, characterization and photophysical properties, perovskite devices, and current challenges in this field. We develop a comprehensive overview of the current state of the art and offer readers an informed perspective of where this field is heading and what challenges we have to overcome to get to successful commercializatio