Inorganic Halide Research Articles

Lead-Free All Inorganic Rubidium Copper Halide Rb2CuX3 (X = Cl, Br) for UVC Photodetector with Fast Response.

Recently, lead halide perovskites have shown great potential in the photodetection field. Unfortunately, the existence of toxic lead elements restricts their practical application. Herein, high-quality 1D lead-free crystals Rb2CuX3 (X = Cl, Br) are successfully synthesized in an acidic medium. Rb2CuCl3 and Rb2CuBr3 display violet photoluminescence emission peaks at 401 and 388nm with a high exciton lifetime of 12.78 and 59.67µs, respectively, which is due to self-trapped excitons (STE). Furthermore, a photodetector is fabricated to detect harmful UVC radiation with Rb2CuBr3 as a light absorber. The proposed photodetector has a responsivity of 0.92mAW-1 and a specific detectivity of 1.57 × 109 Jones with a fast response speed of 2.67/2.70 µs for rise/fall time, respectively. In addition, both the samples show good stability against open air, and continuous ultraviolet light (254nm), as well as good thermal stability which is necessary for device fabrication. Thus, the present study suggests that stable, non-toxic, and environment-friendly Rb2CuX3 (X = Cl, Br) can be a promising candidate for future UVC optoelectronic devices.

Stabilizing Wide‐Bandgap Perovskite with Nanoscale Inorganic Halide Barriers for Next‐Generation Tandem Technology

AbstractWide‐bandgap (WBG) perovskite solar cells (PSCs) play a crucial role in advancing perovskite‐based tandem solar cells. In WBG perovskite films, grain boundary (GB) defects are the main contributors to open‐circuit voltage (VOC) deficits and performance degradation. This report presents an effective strategy for passivating GBs by incorporating an inorganic protective layer and reducing the density of GBs in perovskite films. This is achieved by integrating potassium thiocyanate (KSCN) into I‐Br mixed halide WBG perovskites. It is reported for the first time that the incorporation of KSCN creates band‐shaped barriers along the GBs. In addition, KSCN enlarges the grains of perovskite film. Elemental and structural analyses reveal that these barriers are composed of potassium lead halide. Incorporating KSCN significantly enhances the fill factor and VOC of WBG single‐junction PSCs by reducing trap density. This results in high power conversion efficiencies of 19.22% (bandgap of 1.82 eV), 20.45% (1.78 eV), and 21.54% (1.70 eV) with a C60/bathocuproine electron transport layer, and 18.51% (1.82 eV) with a C60/SnO2. Furthermore, both operational and shelf stabilities are significantly improved due to reduced light‐induced halide segregation. By using inorganic‐halide‐passivated WBG sub‐cells, a monolithic all‐perovskite tandem solar cell with an efficiency of 27.04% is demonstrated.

Single‐Component White Emissive Organic–Inorganic Hybrid Copper Halide Composite Films for Remote UV‐pumped White Light‐Emitting Diodes with High Color Rendering Index

AbstractLead‐free organic–inorganic metal halides (OIMHs) are highly desirable owing to their remarkable properties including low toxicity, structural diversity, high stability, and solution processability. Nevertheless, the development of their single‐component white emissive films remains a formidable challenge for remote white light‐emitting diodes (WLEDs) application. In this work, (C16H36N)2Cu2I4/polyvinylidene fluoride (PVDF) white emissive composite film is successfully fabricated through an in situ solvent evaporation crystallization process at room temperature. The elemental analysis and bonding between (C16H36N)2Cu2I4 and PVDF are demonstrated by X‐ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) measurements. In addition, this composite film exhibits a broadband white emission with two peaks. Notably, the best photoluminescence quantum yields (PLQYs) of the PVDF based composite film reaches an impressive 96.7%. A (C16H36N)2Cu2I4/PVDF based remote UV‐pumped WLEDs with an impressive color rendering index of 95.5 is realized. Finally, the in situ fabrication method is expanded to fabricate (C16H36N)2Cu2I4/polyacrylonitrile (PAN) composite films, and we further realized their single component remote WLEDs.

DFT assessment on the future prospects of inorganic lead-free halide double perovskites Cs2ABI6 (AB: GeZn, SnBe) for energy conversion technologies

In this study, we employed density functional theory (DFT) calculations to investigate the structural, elastic, electronic, optical, and thermoelectric properties of Cs2ABI6 (AB: GeZn, SnBe) halide double perovskites (HDPs). We employed the full-potential linear augmented plane-wave (FP-LAPW) method, incorporating the generalized gradient approximation (GGA) and Tran-Blaha modified Becke-Johnson (TB-mBJ) approach for the exchange-correlation potential. We found that the HDPs are stable in a cubic structure (space group Fm-3m), as indicated by phase stability analysis, formation energies, tolerance factor, and elastic constants. The compounds exhibits ductile behavior, as assessed by Poisson's and Pugh's ratios. The electronic band structures of Cs2GeZnI6 and Cs2SnBeI6 exhibit indirect band gaps (X-L) of 1.124 eV and 1.551 eV, respectively, as calculated using the TB-mBJ approximation. Optical spectra were evaluated over the 0–13 eV energy range, including the dielectric functions, extinction coefficient, electron energy loss, refractive index, optical conductivity, reflectivity, and absorption coefficient. Additionally, we calculated thermoelectric parameters across a range of chemical potentials and temperatures to assess their suitability for thermoelectric applications. Our results suggest that these compounds are highly promising candidates for both optoelectronic and thermoelectric devices.

Strain effect on the physical properties of novel Mg3NI3 perovskite material: First principle DFT analysis

Inorganic perovskite-based substances have become a major attraction to solar technology. Inorganic cubic Mg3NI3 perovskites have generated a heap of fascination owing to their distinctive optical, electrical, and structural features. The photovoltaic and optoelectronic industries prioritize lead-free, atomically tailored metal halide perovskites due to the need to address lead (Pb) toxicity and instability. This study assessed the optical, structural, and electrical parameters of Pb-free inorganic halide perovskites Mg3NI3 as a function of biaxial compressive and tensile strain, leveraging first-principles density-functional theory (FP-DFT). Refractive index, absorption coefficient, reflectivity, dielectric function, and tolerance factor are a few additional optical parameters that are computed and processed. The bandgap of the planar Mg3NI3 molecule is 0.412 eV (PBE) when SOC is not applied. The bandgap reduces to 0.363 eV (PBE) at its Γ(gamma) and R-point when the subjective SOC effect is taken into consideration. This compound's bandgap will narrow under tensile strain and expand under compressive strain, depending on whether the SOC effect is applied or not. Several elastic factors are anticipated, including the bulk modulus, Pugh's ratio, elastic constants, anisotropic factors, and Poisson's ratio. Electronic property calculations using band mechanism and density of states (DOS) suggest that Mg3NI3 have a bandgap that is indirect and semiconductive. The elastic properties of this material were found to be mechanically stable, anisotropic, and ductile. In the photon energy range suitable for solar cells, the spikes in the dielectric constant of Mg3NI3 are seen. Our findings point to the prospect of Mg3NI3 as a non-toxic, high-performance, low-cost material for implementation in solar cells and different semiconductor devices.

Microscopic mechanism of water-assisted diffusional phase transitions in inorganic metal halide perovskites.

The stability of perovskite materials is profoundly influenced by the presence of moisture in the surrounding environment. While it is well-established that water triggers and accelerates the black-yellow phase transition, leading to the degradation of the photovoltaic properties of perovskites, the underlying microscopic mechanism remains elusive. In this study, we employ classical molecular dynamics simulations to examine the role of water molecules in the yellow-black phase transition in a typical inorganic metal halide perovskite, CsPbI3. We have demonstrated, through interfacial energy calculations and classical nucleation theory, that the phase transition necessitates a crystal-amorphous-crystal two-step pathway rather than the conventional crystal-crystal mechanism. Simulations for CsPbI3 nanowires show that water molecules in the air can enter the amorphous interface between the black and yellow regions. The phase transition rate markedly increases with the influx of interfacial water molecules, which enhance ion diffusivity by reducing the diffusion barrier, thereby expediting the yellow-black phase transition in CsPbI3. We propose a general mechanism through which solvent molecules can greatly facilitate phase transitions that otherwise have prohibitively high transition energies.

Electrochemical performance of rGO anchored with inorganic halide perovskite LiZrBr3 composite for effective supercapacitor electrodes

Electrochemical performance of rGO anchored with inorganic halide perovskite LiZrBr3 composite for effective supercapacitor electrodes

Design and performance exploration of Pb-free low-cost all-inorganic perovskite-inspired CuAgBi2I8 solar cells: theoretical approach

Abstract Organic–inorganic halide perovskites have demonstrated great potential for photovoltaic applications owing to their unprecedented optoelectronic properties and low manufacturing costs. However, the commercialization of this technology is hindered by its thermal instability and inherent toxicity. In this study, SCAPS-1D simulation software was used to study the performance of solar cell based on CuAgBi2I8, which is a novel inorganic non-toxic lead-free perovskite-inspired material. Different electron transport layers (TiO2, In2S3, ZnO, Zn0.75Mg0.25O,SnO2 and SrTiO3) and hole transport layers (CuI, PEDOT:PSS, CuSCN and Cu2O) were studied, our research indicated that SnO2 and NiO formed the optimal combination. Further analysis revealed that the optimal absorption layer thickness was 900 nm, the absorption layer doping concentration should be less than 1 × 1013 cm−3 and the defect density should be less than 1 × 1014 cm−3. The optimal thickness of SnO2 and NiO was 30 nm, the optimal doping concentration of SnO2 and NiO was 1 × 1020 cm−3, the defect density of absorber layer/SnO2 and absorber layer/NiO interfaces should be less than 1 × 1012 cm−3, C was the optimal back electrode material. Consequently, the optimal device configuration was identified as FTO/SnO2/CuAgBi2I8/NiO/C, the efficiency was improved from original 2.76% to 19.10% after above optimization. These results indicate that solar cell with CuAgBi2I8 as the absorber layer is a potential alternative to organic–inorganic lead halide perovskite solar cells.

Determination of the particle size distribution of cube-shaped colloidal perovskite quantum dots from photoluminescence spectra: A combined theoretical-experimental approach.

A theoretical-experimental approach is proposed to convert the photoluminescence spectra of colloidal perovskite quantum dot ensembles into accurate estimates for their intrinsic particle size distribution functions. Two main problems were addressed and properly correlated: the size dependence of the first excitonic transition in a single cube-shaped quantum dot and the inhomogeneous broadening of the fluorescence line shape due to the size nonuniformity of the chemically prepared quantum dot suspension in addition to the single-dot homogeneous broadening. By applying the reported methodology to CsPbBr3 quantum dot samples belonging to the strong and intermediate confinement regimes, the calculated size distributions exhibited close agreement with those obtained from transmission electron microscopy, with precise estimates for the average particle size and standard deviation. Specifically for strongly confined ultrasmall CsPbBr3 quantum dots, the presented spectroscopic model for size distribution computation is based on a new analytical expression for the size-dependent bandgap, which was developed within the framework of the finite-depth square-well effective mass approximation accounting for band nonparabolicity effects. Such a quantum mechanical approach correctly predicts the expected transition to the intermediate confinement regime in sufficiently large quantum dots, which are traditionally described by the well-known bandgap equation in the infinite potential barrier limit with a spatially correlated electron-hole wavefunction and nonparabolic carrier effective masses. The proposed calculation scheme originates from general theoretical considerations so that it can be readily adapted to semiconductor quantum dots of many other systems, from all inorganic metal halides to hybrid perovskite materials, regardless of the adopted chemical synthesis route.

Synthesis and stability of one-dimensional red-emitting manganese-based Organic–inorganic halide

Pb-based halides are a highly promising class of materials due to their exceptional optoelectronic and magnetic properties. However, lead-based halides’ high toxicity and instability have detrimentally affected their actual applications. To address these issues, we investigated a lead-free one-dimensional manganese (Mn)-based organic–inorganic halide (TZI)MnCl3 (TZI = thiazolidin-3-ium). The red-emitting (TZI)MnCl3 demonstrated photoluminescence quantum yields of up to 46.4 % and 30.6 % when excited by light at wavelengths of 373 nm and 446 nm, respectively. Furthermore, (TZI)MnCl3 exhibited high stability under various conditions, highlighting its potential for optoelectronic applications.

Rod‐Like Microcrystal Scintillators Based on Organic–Inorganic Hybrid Copper Halides for X‐Ray Imaging

AbstractCopper‐based organic–inorganic hybrid halides (OIHHs) have garnered significant interest in X‐ray imaging due to their flexible structural adjustability, efficient light emission, strong X‐ray absorption, etc. Herein, four copper‐based OIHH crystals composed of the same organic ligands (isopropyl triphenylphosphonium cations, IPP+) and inorganic parts (Cu2I42−) are synthesized by varying the ratios of raw materials and types of reaction solvents. Although these crystals share identical structures, they exhibit different luminescent behaviors (blue, green, white, and yellow) attributed to vacancy defects originating from CuI. Notably, the novel copper‐based OIHH (CP2) with green emission shows the best luminescence efficiency (99.54%) and excellent scintillation performance (50675 photons MeV−1). The traditional technology of scintillation screens mixing scintillator powders and polymers often results in light scattering due to powder aggregation and inhomogeneity. To address this challenge, the dispersant polyvinyl pyrrolidone is introduced to prepare uniform rod‐like microcrystals of CP2. The scintillation screen based on CP2 microcrystals achieves a high spatial resolution of 16–18 lp mm−1, surpassing the resolution of most copper‐based OIHH scintillators. Furthermore, it is imaging capabilities are validated using a commercial X‐ray flat panel detector, demonstrating imaging performance comparable to that of commercial scintillators.

Multimode Luminescence Tailoring in PMA4Na(In,Sb)Cl8 Organic–inorganic Hybrid Metal Halide via Rigid Benzene Ring Induced Local Lattice Distortion

AbstractLow dimensional organic‐inorganic hybrid metal halide materials have attracted extensive attention due to their superior optoelectronic properties. However, low photoluminescence quantum yields (PLQYs) caused by parity‐forbidden transition hinder their further application in optoelectronic devices. Herein, a novel yellow‐emitting PMA4Na(In,Sb)Cl8 (C7H10N+, PMA+) low‐dimensional OIMHs single crystal with a PLQY as high as 88 % was successfully designed and synthesized, originating from the fact that the doping of Sb3+ effectively relaxes the parity‐forbidden transition by strong spin‐orbit (SO) coupling and Jahn‐Teller (JT) interaction. The as‐prepared crystal shows an efficient dual emission peaking 495 and 560 nm at low temperature, which are ascribed to different levels of 3P1→1S0 transitions of Sb3+ in [SbCl6]3− octahedral caused by JT deformation. Moreover, wide‐range luminescence tailoring from cyan to orange can be achieved through adjusting excitation energy and temperature because of flexible [SbCl6]3− octahedral in the PNIC lattice. Based on a relative stiff lattice environment, the 560 nm yellow emission under 350 nm light excitation exhibits abnormal anti‐thermal quenching from 8 to 400 K owing to the suppression of non‐radiative transition. The multimode luminescence regulation enriches PMA4Na(In,Sb)Cl8 great potential in the field of optoelectronics such as temperature sensing, low temperature anti‐counterfeiting and WLED applications.

Customizing Aniline-Derived Molecular Structures to Attain beyond 22 % Efficient Inorganic Perovskite Solar Cells.

The characteristics of the soft component and the ionic-electronic nature in all-inorganic CsPbI3-xBrx perovskite typically lead to a significant number of halide vacancy defects and ions migration, resulting in a reduction in both photovoltaic efficiency and stability. Herein, we present a tailored approach in which both anion-fixation and undercoordinated-Pb passivation are achieved in situ during crystallization by employing a molecule derived from aniline, specifically 2-methoxy-5-trifluoromethylaniline (MFA), to address the above challenges. The incorporation of MFA into the perovskite film results in a pronounced inhibition of ion migration, a significant reduction in trap density, an enhancement in grain size, an extension of charge carrier lifetime, and a more favorable alignment of energy levels. These advantageous characteristics contribute to achieving a champion power conversion efficiency (PCE) of 22.14 % for the MFA-based CsPbI3-xBrx perovskite solar cells (PSCs), representing the highest efficiency reported thus far for this type of inorganic metal halide perovskite solar cells, to the best of our knowledge. Moreover, the resultant PSCs exhibits higher environmental stability and photostability. This strategy is anticipated to offer significant advantages for large-area fabrication, particularly in terms of simplicity.

Atomistic insight into the device engineering of inorganic halide perovskite solar cells

Perovskites provide a promising pathway for fabricating efficient and lightweight solar cells, which could be game-changers in the renewable energy landscape. Yet, the phase stability and device design are still the key issues of perovskite-based photovoltaics. Herein, we evaluated the phase stability of CsPbX3 (X = I, Br, and Cl) upon analyzing the lattice dynamics from first-principles and then predicted fundamental properties including bandgap, carrier mobility, and optical absorption as input to optimize the device design of solar cell. A maximum power conversion efficiency (PCE) of 12.36 % was achieved for a CsPbBr3-based solar cell. Those findings highlight the potential of CsPbX3 perovskites for high-efficiency solar cells. The computational approach provides a comprehensive understanding of the material's structural stability, charge-carrier dynamics, and optoelectronic characteristics. The collective analysis enables a holistic understanding of CsPbX3 perovskites and provides a roadmap for future advancements in perovskite solar-cell technology.

Efficient Blue Emission in Organic–Inorganic Metal Halide (TEA)2InCl5 Triggered by Bi3+‐Doping

AbstractLead‐free 0D In‐based organic–inorganic metal halides (OIMHs) have attracted tremendous attention because of their nontoxicity, environmental stability, and excellent photoluminescence properties. However, it remains controversial and unclear whether the luminous division exists in ns2 doping In‐based materials, as the majority of In‐based materials are considered non‐luminous. Herein, a series of Bi3+‐doped (TEA)2InCl5 (TEA = tetraethylammonium) crystals are synthesized and it is determined that the blue emission stemmed from Bi ions. Remarkably, the photoluminescence quantum yield (PLQY) of the blue emission at 469 nm reached 69.69% under 371 nm excitation, exceeding those of previously reported Bi3+‐doped OIMHs. In addition, pristine and Bi3+‐doped compounds exhibited excellent structure and optical stability under humid conditions. This study provides new insights into the photoluminescence properties of In‐based OIMHs, especially regarding the high‐efficiency emission of Bi3+‐doped materials.

High‐Stability Hybrid Antimony Halides for Thermometry in Power System Component or Circuit Monitoring

AbstractOrganic–inorganic metal halides (OIMHs) possess low preparation costs and high photoluminescence quantum yield. Within a specific range, the temperature‐dependent nature of OIMHs' luminescent lifetime facilitates temperature sensing and thermal imaging functionalities. In this study, a non‐toxic (C10H22N)6SbBr9·H2O ([C10H22N]+ is 4‐(tert‐buty)cyclohexanamine cation) with a 0D structure crystallized in the Pbcn space group is obtained. Under blue light excitation at room temperature, it demonstrates intense broad emission centered at 635 nm. Further investigation into the correlation between temperature and photoluminescence lifetime has unveiled exceptional temperature sensing precision. The relative sensitivities within the range of power system temperature alert 30–70 °C lie between 2.5% and 4.5% K−1. This matches the typical high‐temperature warning threshold for power systems. Moreover, after immersion in water and alcohol, the compound maintains remarkable stability, with multiple heating/cooling cycles confirming its reliability under test temperatures. Additionally, a composite thin‐film device composed of (C10H22N)6SbBr9·H2O, showcasing its potential as a stable and durable thermal imaging temperature sensing device is fabricated.

How to Apply Raman Spectroscopy for Single Crystals and Thin Films of Organic–Inorganic Lead Halide Perovskite

How to Apply Raman Spectroscopy for Single Crystals and Thin Films of Organic–Inorganic Lead Halide Perovskite

Roles of defects in perovskite CsPbX3 (X=I, Br, Cl): a first- principles investigation

Inorganic lead halide perovskite CsPbX3 (X=I, Br, Cl) have a promising application in optoelectronic fields due to their excellent photovoltaic properties. The defects, which have a significant impact on the performance of materials, are often introduced during the synthesis process. However, there is still a lack of systematic theoretical investigation of the effects of these defects. In this study, the effects of vacancies and H-atom interstitial point defects on the structural, electronic and optical properties of CsPbX3 are systematically investigated by using first-principles approach based on density-functional theory. The calculated results show that the introduction of different defects have significantly effect on the band gap, effective mass, semiconductor properties, ion migration and optical absorption coefficient of the perovskite materials. It is also found that VCs and VPb defects introduce shallow transition levels that do not negatively impact the optoelectronic properties. However, VX and interstitial H defects generate deep transition levels within the bandgap, which acts as non-radiative recombination centers and reduce the optoelectronic performance of the perovskite material. This study contributes to the understanding of the nature of halide chalcogenides and optimally regulating the performance of optoelectronic devices.

Exploring the inorganic perovskite materials Mg3SbX3 (Where, X=I, Br, Cl and F) through the perspective of density functional theory: Adjustment of physical characteristics as consequence of strain

The solar technology industry has lately given inorganic perovskite materials an abundance of thought because of their unique optical, electrical and structural characteristics. Issues pertaining to lead (Pb) toxicity and instability require being referred to promptly, making lead-free atomically designed metal halide perovskites of foremost importance to the photovoltaic and optoelectronic industries. Perovskites, a class of inorganic metal halide semiconductors, have variant similarities with Mg3SbX3 (X = I, Br, Cl and F). According to the space group Pm-3m Mg3SbX3 (X = I, Br, Cl and F) has a cubic perovskite crystal structure. Utilizing first-principles density-functional theory (FPDFT), The intention of this investigation is to analyze how strain and spin-orbit coupling (SOC) impact the structural, electrical, optical and mechanical features of the inorganic cubic perovskite of Mg3SbX3 (X = I, Br, Cl and F). At the point between R and Γ, the Mg3SbI3,Mg3SbBr3,Mg3SbCl3 molecule displays an indirect bandgap of 0.105 eV, 0.957 eV, 1.728 eV. At the Γ point, the Mg3SbF3 molecule displays a direct bandgap of 3.184 eV. The bandgaps of the Mg3SbI3,Mg3SbBr3,Mg3SbCl3 and Mg3SbF3 perovskites are 0.198 eV, 1.203 eV, 1.901 eV and 3.723 eV respectively, when considering the spin-orbital coupling (SOC) quantum influence. A wider bandgap is investigated for increasing compressive strain while a smaller bandgap is observed for increasing tensile strain. Apart from the elastic constants and anisotropic factors, other factors that are anticipated include Pugh's ratio, Poisson's ratio, bulk modulus and others. Isotropic, ductile and mechanically stable are the words that best describe these materials, according to the elastic property evaluations. In the photon energy range that is appropriate for solar cells, the dielectric constant spikes of Mg3SbX3 are found to be visible. Therefore, Mg3SbX3 (X = I, Br, Cl and F) perovskite is a good material to use in solar cells for managing light and producing electricity.

Probing the Impact of Four BSF Layers on MASnI3‐Based Lead‐Free Perovskite Solar Cells for >33% Efficiency

AbstractThis study systematically investigates the impact of various layers of the back surface field (BSF) on the performance of CH₃NH₃SnI₃ (MASnI₃)‐based lead‐free mixed organic–inorganic halide perovskite solar cells. By employing SCAPS‐1D (Solar Cell Capacitance Simulator in One Dimension) simulation software, the behavior of solar cells is analyzed incorporating BSF layers of CuI, NiO, ZnTe, and CBTS. The findings indicate that the inclusion of these BSF materials significantly enhances power conversion efficiency (PCE), with CBTS showing the highest PCE of 33.57%. The energy band diagrams reveal that the BSF layers effectively reduce recombination losses at the rear interface and improve charge carrier collection. Detailed analysis of photovoltaic parameters, such as open‐circuit voltage (Voc), short‐circuit current density (Jsc), fill factor (FF), and overall PCE, underscores the superiority of CBTS as optimal BSF materials. Temperature variation studies demonstrate that CBTS maintains superior performance across a range of temperatures, highlighting its potential for high‐efficiency, thermally stable perovskite solar cells. This comprehensive investigation provides valuable insights for optimizing the design and performance of MASnI₃‐based perovskite solar cells, with the aim of efficiencies greater than 33%.