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Abstract Chalcogenide perovskites have garnered increasing attention as stable, non‐toxic alternatives to lead halide perovskites. However, their conventional synthesis at high temperatures (>1000 °C) has hindered widespread adoption. Recent studies have developed low‐to‐moderate temperature synthesis methods (<600 °C) using reactive precursors, yet a comprehensive understanding of the pivotal factors affecting reproducibility and repeatability remains elusive. This study delineates the critical factors in the low‐temperature synthesis of BaMS₃(M═Zr, Hf, Ti) compounds and presents a generalized framework. Innovative approaches are developed for synthesizing BaMS₃compounds using this framework involving organometallics for solution deposition. The molecular precursor routes, employing metal acetylacetonates to generate soluble metal–sulfur bonded complexes and metal–organic compounds to produce soluble metal‐thiolate, metal‐isothiocyanate, and metal‐trithiocarbonate species, are demonstrated to yield carbon‐free BaMS₃. These methods have achieved the most contiguous films of BaZrS₃and BaHfS₃using solution deposition to date. Furthermore, a hybrid solution processing method involving stacking sputter‐deposited Zr and solution‐deposited BaS layers is employed to synthesize a contiguous, oxygen‐free BaZrS₃film. The diffuse reflectance measurements indicate a direct bandgap of ≈ 1.85 eV for the BaZrS₃films and ≈ 2.1 eV for the BaHfS₃film under investigation. 

Recently, chalcogenide perovskites, of the form ABX3, where typically A = alkaline earth metals Ca, Sr, or Ba; B = group IV transition metals Zr or Hf; and X = chalcogens S or Se, have become of interest for their potential optoelectronic properties. In this work, we build upon recent studies and show a general synthesis protocol, involving the use of carbon disulfide insertion chemistry, to generate highly reactive precursors that can be used towards the colloidal synthesis of numerous ABS3 nanomaterials, including BaTiS3, BaZrS3, BaHfS3, α-SrZrS3 and α-SrHfS3. We overcome the shortcomings in the current literature where BaZrS3 nanoparticles are synthesized in separate phases via colloidal methods and lack a reproducible protocol for orthorhombic perovskite nanoparticles. We present a high-temperature, hot-injection method that reliably controls the formation of the colloidal BaZrS3 nanoparticles with the Pnma orthorhombic distorted perovskite structure. We show that the alternate phase, most notably denoted by its extra peaks in the pXRD pattern, is distinct from the distorted perovskite phase as it has a different bandgap value obtained via UV-vis measurements. We also show that the reaction byproducts, resulting from the use of oleylamine and CS2, have their own photoluminescence (PL), and their residual presence on the surface of the nanoparticles complicates the interpretation of PL from the nanoparticles. The utility of these nanomaterials is also assessed via the measurement of their absorption properties and in the form of highly stable colloidal inks for the fabrication of homogeneous, crack-free thin films of BaZrS3 nanoparticles. 

Solution-chemistry fabrication of semiconductor materials is an attractive synthesis method that allows for easy post-synthesis use in various applications. In this work, we investigate the solution-phase synthesis of a lesser-studied class of semiconductor materials, the binary sulfides of alkaline-earth (AE) metals and their potential for forming polysulfides. Studies have shown that metal polysulfides are widely applied as cathode materials in metal–sulfur batteries and isolated metal polysulfides outside of sulfur-containing solutions are quite rare. Other studies have shown that this material system has the potential to be a wide-bandgap semiconductor or superconducting electride and can also be used as an AESn precursor to access certain AE-M-S ternary materials. We show that the synthesis of Ba and Sr polysulfides is strongly correlated to the reaction temperature and that the length of the Sn2− oligomer chain is the dependent variable. To the best of our knowledge, we also report the synthesis of a previously unreported polymorph of SrS2. With bandgaps estimated via UV-vis spectroscopy, spanning the upper energy range of the visible spectrum (2.4–3.0 eV), the AE polysulfides have potential for semiconducting applications, such as displays, transparent conducting oxides, or tandem photovoltaics, among others. Paired with their high crystal abundance and relatively low toxicity, these materials make good candidates for future studies as wide-bandgap semiconductors. 

Chalcogenide perovskites are gaining prominence as earth-abundant and non-toxic solar absorber materials, crystallizing in a distorted perovskite structure. Among these, BaZrS3 has attracted the most attention due to its optimal bandgap and its ability to be synthesized at relatively low temperatures. BaZrS3 exhibits a high light absorption coefficient, excellent stability under exposure to air, moisture, and heat, and is composed of earth-abundant elements. These properties collectively position BaZrS3 as a promising candidate for a wide range of applications, although traditional high-temperature synthesis has primarily been a significant challenge. In this review, we provide a critical discussion of the various synthesis methods employed to fabricate BaZrS3, including solid-state synthesis, nanoparticle synthesis, and vacuum-based as well as solution-based approaches to synthesize thin films. We also comprehensively examine the experimentally measured and theoretically calculated optical, optoelectronic, electronic, and defect properties of BaZrS3. Furthermore, this review highlights the functional devices based on BaZrS3, showcasing applications spanning photovoltaics, photodetection, thermoelectrics, photoelectrochemical water splitting, piezoelectricity, and spintronics. Lastly, we propose a future roadmap to maximize the potential of this material. Additionally, this review extends its focus to BaHfS3 and BaTiS3, discussing their synthesis methods, properties, and explored applications, thereby offering a comparative perspective on this emerging family of chalcogenide perovskites. 

Chalcogenide semiconductors, such as BaMS3 (M = Zr and Hf) and Cu2BaSnS4, have attracted growing interest due to the constituent elements’ abundance and reported promising properties. However, the synthesis of these alkaline earth-containing chalcogenides from commonly available metal halides has generally been unsuccessful and has traditionally relied on expensive organometallic precursors or vacuum processing techniques, which hinder widespread research on these materials. In this study, we conducted thermodynamic calculations and developed chloriphilicity and iodiphilicity scales for various metals, leveraging their relative affinities for chlorine and iodine, respectively, compared to their corresponding metal sulfides. Utilizing these scales, we introduced a K2S–H2S system to address the affinity of alkaline earth metals for chlorine and iodine. This approach enables the synthesis of these intriguing chalcogenide materials through solution-based methods using metal chloride and metal iodide precursors. This system demonstrates remarkable efficacy for both sulfide and selenide semiconductors. 

Chalcogenide perovskites have recently attracted significant attention for renewable energy applications due to their predicted combination of air, moisture, and thermal stability, which has been experimentally validated, along with their excellent optoelectronic properties, which are still under experimental investigation. While historically requiring high synthesis temperatures, some solution-processed routes have recently emerged for synthesizing chalcogenide perovskites, such as BaZrS3 and BaHfS3, at temperatures below 600 °C. This study discusses several experimental challenges associated with the moderate-temperature synthesis of solution-deposited chalcogenide perovskites. Firstly, we identify Ruddlesden–Popper (RP) phases as thermodynamically stable competing secondary phases in perovskite synthesis. High sulfur pressures favor the formation of BaZrS3 or BaHfS3, whereas lower sulfur pressures result in a mixture of perovskite and RP phases. Additionally, we briefly discuss the mechanism of moderate-temperature synthesis of chalcogenide perovskites, including some of the morphological and optoelectronic challenges it presents, such as grain overgrowth, secondary phase contamination entrapment, and the presence of mid-band gap emissions. Finally, we address the importance of substrate selection and the potential presence of Ca- and Na-based impurities originating from cation out-diffusion from glass substrates. Addressing these challenges will be crucial as these unique materials continue to be investigated for applications in optoelectronic devices. 

Policies aiding biofuels have supported farm income and rural communities but have also put pressure on food security with questionable benefits related to carbon emissions. Photovoltaics (PV) are poised to become central to the overall energy decarbonization strategy, but because of land requirements they are likely to be developed on farmland, reigniting concerns related to food security. In this work, we study strategies for co-producing food and energy from corn croplands. We find that while traditional PV displaces crops, they can harvest orders of magnitude more energy per unit of land than biofuels. Additionally, systems with elevated PV panels (called PV Aglectric, Agrivoltaics, or Agrophotovoltaics) that allow for crop production underneath them can increase energy production and reduce carbon emissions with minimal impact on crop production. This technology can ease the trade-off between farm income, energy production, crop production, and energy decarbonization. Adoption of PV Aglectric systems may be hindered by high capital costs, but this barrier could be overcome with policy support, especially when crop prices are highly volatile. 

Agrivoltaic systems, which achieve sustainable food and energy co-production (SFE) by installing photovoltaics (PVs) on farmland, offer a climate-resilient solution for meeting ”full Earth” needs while adhering to land limitations. However, limited research on major row crops, such as corn (Zea Mays), constrains the widespread adoption of agrivoltaics. To bridge this research gap, a two-step process was executed. First, extensive corn growth data was collected from neighboring regions, specifically segregating ”with-PV” (shaded) and ”without-PV” (unshaded) areas under real farming conditions. Using data from unshaded areas, the APSIM plant model was calibrated. Subsequently, an analytical shadow model was used to compute the spatiotemporal shadow distribution (SSD) for each row of corn between PV panels. This SSD data helped validate the APSIM model using the experimental corn yield data from shaded areas. 

Synthesis of homoleptic zirconium and hafnium dithiocarbamate via carbon disulfide insertion into zirconium and hafnium amides were investigated for their utility as soluble molecular precursors for chalcogenide perovskites and binary metal sulfides. Treating M(NEtR)4 (M= Zr, Hf and R= Me, Et) with CS2 resulted in quantitative yields of homoleptic Group IV dithiocarbamates. Zr(2-S2CNMeEt) (1), Zr(2-S2CNEt2)4 (2), and Hf(2-S2CNEt2)4 (4), a rare example of a crystal of a homoleptic hafnium CS2 inserted amide species, were characterized. A computational analysis confirmed assignments for IR spectroscopy. To exemplify the utility of the Group IV dithiocarbamates, a solution-phase nanoparticle synthesis was performed to obtain ZrS3 via the thermal decomposition of Zr(S2CNMeEt)4. 

Thin film photovoltaics are a key part of both current and future solar energy technologies and have been heavily reliant on metal chalcogenide semiconductors as the absorber layer. Developing solution processing methods to deposit metal chalcogenide semiconductors offers the promise of low-cost and high-throughput fabrication of thin film photovoltaics. In this review article we lay out the key chemistry and engineering that has propelled research on solution processing of metal chalcogenide semiconductors, focusing on Cu(In,Ga)(S,Se)2 as a model system. Further, we expand on how this methodology can be extended to other emerging metal chalcogenide materials like Cu2ZnSn(S,Se)4, copper pnictogen sulfides, and chalcogenide perovskites. Finally, we discuss future opportunities in this field of research, both considering fundamental and applied perspectives. Overall, this review can serve as a roadmap to researchers tackling challenges in solution processed metal chalcogenides to better accelerate progress on thin films photovoltaics and other semiconductor applications.