Inorganic Halide Perovskite Research Articles

Continuous Nanomanufacturing of Inorganic Lead Halide Perovskite Nanocrystals with High-Concentration Precursors.

The microscale flow preparation scheme has been widely used in the preparation of inorganic perovskite nanocrystals (NCs). It is considered to be the most promising method for large-scale production. Recently, it has been suggested that increasing the precursor concentration can further improve efficiency, but there is still a lack of understanding of high-concentration synthesis. Here, we develop a microscale flow synthesis scheme using high-concentration precursors, and the typical concentration value in the reaction phase reaches 0.035 mol/L using cesium acetate. The CsPbBr3 NCs with sharp photoluminescence (PL) at 515.7 nm can be obtained, and their PL quantum yield after post-treatment exceeds 90%. The effect of the molar ratio of Pb/Cs (Rm), reaction time, reaction temperature, and excess ligands on this flow reaction is studied. Several new phenomena are observed in our experiment. At 120 °C, some Cs4PbBr6 NCs exist in addition to the usual CsPbBr3 nanoplatelets. Excess ligands lead to the formation of numerous Cs4PbBr6 NCs with a bright green PL, and these NCs will spontaneously transform into a nonemission form in the film. Moreover, mixed-halide CsPbBrxI3-x NCs and CsPbI3 NCs are also prepared in this scheme, and then they are used to obtain LEDs in a range of colors.

Device modelling and numerical analysis of high-efficiency double absorbers solar cells with diverse transport layer materials

Recently, a lot of focus has been placed on cesium lead iodide (CsPbI3) since it is considered a potentially useful inorganic halide perovskite with improved stability. Moreover, another potential absorber material is the mixed chalcogenide CZTSSe, which is abundant on Earth, cheap, environmentally acceptable, and has excellent photovoltaic performance. This research numerically simulated a novel double absorber solar cell structure employing CsPbI3 and CZTSSe absorbers in the active layer in SCAPS-1D. The current study analyses the effects of various electron and hole transport materials, back contact material's work functions, working temperatures, variations in defect concentration, and absorber thickness on the performance of photovoltaic devices. After researching a variety of distinct arrangements of double absorber solar cells, it was realized that the FTO/STO/CsPbI3/CZTSSe/NiO/W cell configuration exhibited the best overall performance with an open circuit voltage (Voc) at 1.0207 V, a short circuit current density (Jsc) at 41.815426 mA/cm2, Fill Factor (FF) at 87.50 %, and a Power Conversion Efficiency (PCE) at 37.35 %. The modeling of the device showed that a thickness of around 1.4 µm for the CZTSSe absorber is optimal. This simulation shows that when the working temperature in the cell and the defect concentration in the absorber increase, the efficiency of the device reduces uniformly, and the device is stable at 300 K temperature. In conclusion, if the material's work function is greater than 5.20 eV, then it is suitable for use as an anode.

Novel One-Dimensional Organic–Inorganic Hybrid Halide Perovskite Material with Coexistence of High Phase Transition Temperature and Corresponding Dielectric Response

Novel One-Dimensional Organic–Inorganic Hybrid Halide Perovskite Material with Coexistence of High Phase Transition Temperature and Corresponding Dielectric Response

Highly luminescent CsPbX3/PMMA (X=Br, I) composites with improved stability for full-color Micro-LED displays

Inorganic metal halide perovskite quantum dots (PQDs) have recently emerged as promising candidates for color conversion materials in Micro-LED displays, due to their outstanding color purity, high absorption coefficient, tunable emission wavelength. However the inferior stability and undesirable photoluminescence quantum yield (PLQY) restrict their particle applications. Herein, CsPbX3/PMMA (X = Br, I) composites with improved stability and optical performance were successfully prepared by a general and mild in-situ polymerization strategy. The ester carbonyl (CO) group in MMA formed complexes with Pb2+, leading to the in-situ thermal polymerization of polymethyl methacrylate (PMMA) under the action of the initiator. The multifunctional PMMA can efficiently passivate halogen vacancies while acting as a barrier against the degradation caused by heat, water, and oxygen. As a result, the PLQYs and stability of PMMA-coated CsPbX3 PQDs have been significantly improved. When implementing CsPbX3/PMMA/PDMS composites as color conversion layers in Micro-LEDs, they achieve an impressive color gamut of 127.23% with excellent stability. We believe our work will stimulate the exploration of perovskite/polymer composites for industrial Micro-LED applications.

Room temperature polaritonic soft-spin XY Hamiltonian in organic–inorganic halide perovskites

Abstract Exciton–polariton condensates, due to their nonlinear and coherent characteristics, have been employed to construct spin Hamiltonian lattices for potentially studying spin glass, critical dephasing, and even solving optimization problems. Here, we report the room-temperature polariton condensation and polaritonic soft-spin XY Hamiltonian lattices in an organic–inorganic halide perovskite microcavity. This is achieved through the direct integration of high-quality single-crystal samples within the cavity. The ferromagnetic and antiferromagnetic couplings in both one- and two-dimensional condensate lattices have been observed clearly. Our work shows a nonlinear organic–inorganic hybrid perovskite platform for future investigations as polariton simulators.

Ester‐Functionalized Polythiophene Interlayers for Enhanced Performance and Stability of Perovskite Solar Cells

AbstractInterfacial defects between the organic–inorganic lead halide perovskite and hole‐transporting layers are one significant factor limiting the performance of the perovskite solar cells (PSCs). These defects typically result from either lead or halide atom vacancies or under‐coordinated Pb2+ atoms, which act as recombination centers for holes. To address this, it is demonstrated that a thin layer of a poly(bithiophene ester) (PBTE) or a poly(terthiophene diester) (PTTDE) introduced between the FA0.92MA0.08Pb(I0.92Br0.08)3 (MA+ = methylammonium; FA+ = formamidinium) perovskite and spiro‐OMeTAD hole transporting material (HTM) layers improves the device stability and power‐conversion efficiency (PCE). The PCE improvements are primarily associated with enhanced open‐circuit voltage and fill factor arising from Lewis‐base passivation of under‐coordinated Pb2+ through interaction with the polymer carbonyl groups, as well as enhanced charge transfer between the perovskite and HTM layers facilitated by the conjugated thiophene functionalities of the polymeric interlayer. Furthermore, the examined polymers improve the thermal and moisture stability of the devices. Encapsulated PSCs with PBTE and PTTDE retain 89 ± 1 and 94 ± 3% of their initial PCE after 1440 h at 65 °C under 0.5‐sun irradiation, respectively, while PSCs without a polymeric interlayer lose almost half of the performance. These results can guide future designs of polymeric interlayers for high‐performance PSCs.

Deep insight into structural and optoelectronic properties of mixed anion perovskites

Abstract Here we present the optoelectronic properties of pure inorganic lead-free halide perovskites in the form of Cs2AgBiX 6 (X = Br, Cl, F, I) using the density functional theory calculations on cubic phase (Fm 3 ̅ m) and tetragonal phase (I4/m). First, all the structures of the two phases were optimized at the PBE level. Structural, electronic, optical properties, phonon, and thermal properties of Cs2AgBiX 6 in cubic (Fm 3 ̅ m) and tetragonal phases (I4/m) were obtained using the VASP code. Tetragonal phases of all compounds of the form Cs2AgBiX 6, except Cs2AgBiBr6, are reported here for the very first time. Among all the Cs2AgBiX 6 (X = F, Cl, Br, I) structures, the cubic phase of Cs2AgBiBr6 was seen to have the highest absorption coefficient along with prominent electronic features that are favorable for optoelectronic applications. Thus, the cubic phase of Cs2AgBiBr6 was selected as the host lattice and bromine atoms were partly replaced with chlorine and iodine atoms. Electronic and optical properties of these mixed halide compounds of Cs2AgBiBr6−xFx, Cs2AgBiBr6−xClx, and Cs2AgBiBr6−xIx where x = 1, 2, 3, 4, 5 are investigated with hybrid functional HSE06 level. The electronic structure revealed that these mixed compounds exhibited indirect band gap nature regardless of the halide substitution (different x concentration) and the band gap of Cs2AgBiBr6 could be varied with the substitutions of fluorine, chlorine, and iodine atoms. Our in-depth analysis shows that Cs2AgBiBr6 and their mixed halides have the potential to become active double perovskite materials for photovoltaic applications and as photocatalysts for water splitting.

Alkali-Metal-Assisted Green-Solvent Synthesis for In Situ Growth of Perovskite Nanocrystals in Porous Materials.

Inorganic metal halide perovskite CsPbX3 (X = I, Br, and Cl) nanocrystals (NCs) are rapidly developed due to their excellent photophysical properties and potential applications in lighting, lasers, and scintillators. However, the materials for growing perovskite NCs are insoluble or hydrolyzed in most green solvents, limiting their further development. Based on rational chemical analysis, an alkali-metal-assisted green-solvent synthesis method for in situ growth of CsPbBr3 NCs within SAPO-34 zeolite with bright luminescence is developed. Water is the only solvent used in the whole process. Surprisingly, by the synergistic effect of the channel structure of SAPO-34 and alkali-metal ions crystallization regulation, the CsPbBr3 NCs embedded in SAPO-34 assisted by Na+ emit bright blue light under ultraviolet illumination, with a 30nm blue shift comparing to the CsPbBr3 NCs assisted by K+. Moreover, CsPbBr3 NCs can also be grown in mesoporous SiO2 SBA-15 and zeolites including ZSM-5, AlPO-5, and SOD, indicating that the method is universal for in situ growth of luminescent perovskite NCs in porous materials. This alkali-metal-assisted green-solvent synthesis provides a new strategy for developing high-quantum-yield, tunable-emission, and stable perovskite luminescent materials.

Efficient Deep‐Blue Light‐Emitting 2D (100)‐Oriented Perovskites and Spectral Broadening by Exciton Self‐Trapping for White‐light Emissions

AbstractEfficient narrow deep‐blue and broadband emissions in layered 2D organic–inorganic hybrid metal halide perovskites (MHPs) are attracting more attention and need further study. In this work, two (100)‐oriented 2D organic‐inorganic hybrid MHPs of (TFI)2PbBr4 and (TFI)2PbCl4·H2O (TFI = 4‐(trifluoromethyl)‐1H‐imidazole) with efficient deep‐blue and bluish‐white emissions are synthesized and the photoluminescence quantum yields (PLQYs) reached up to 81.21% and 20.23%, respectively. As both intrinsic lattice distortions of two crystals with similar crystal structure are almost negligible, they have theoretical deep‐blue emissions empirically. However, the halogen substitution of chlorine (Cl) by bromine (Br) broadened the deep‐blue photoluminescence to a bluish‐white area. Here, the spectral broadening phenomenon is discussed in detail. The (TFI)2PbBr4 film shows a narrow emission with a 16 nm full width at half maximum (FWHM) peaking at 435 nm upon excitation, and an ultraviolet‐pumped light‐emitting diode (LED) prepared by bluish‐white (TFI)2PbCl4·H2O phosphor shows a color rendering index (CRI) of ≈93 and a related color temperature (CCT) of 4162K, indicating their potential applications in deep‐blue and white LEDs, respectively.

Narrowing band gap and enhanced optoelectronic properties in methylammonium lead chloride perovskite under pressure

In this study, we explore the impact of hydrostatic pressure on the structural stability, elastic properties, mechanical behavior, thermodynamics, and optoelectronic characteristics of lead halide perovskite, specifically focusing on CH3NH3PbCl3. Through high-level ab initio simulation techniques, we investigate the lattice squeezing effects on this methylammonium lead chloride perovskite. Our findings reveal that applying hydrostatic pressure squeezes lattice parameters, influences the electronic profile, and results in spin-split band edges. The band gaps in compressed perovskites are observed to be narrower, with the potential for pressure-induced closures, offering new electronic features under various thermodynamic conditions. Because of the high-quality crystal and its optimal optical band gap, we successfully construct an efficient UV-photodetector, highlighting its promising applications in optoelectronics. This work contributes to a deeper atomistic understanding of inorganic halide perovskite behavior under external pressure and demonstrates the potential for realizing enhanced electronic functionalities through pressure conditions.

Machine learning guided rapid discovery of narrow-bandgap inorganic halide perovskite materials

Machine learning guided rapid discovery of narrow-bandgap inorganic halide perovskite materials

Optoelectronic and thermoelectric properties of novel double halide perovskites Na2AgAsX6 (X = Cl, Br) for efficient green solar cells

Inorganic lead-free double halide perovskites have emerged as promising materials in photovoltaic and renewable energy applications. This study investigates the optoelectronic and thermoelectric properties of novel inorganic lead-free double halide perovskite Na2AgAsX6 (X = Cl, Br) materials using accurate PBEsol and nKTB-mBJ schemes within the powerful full potential linear augmented plane wave (FP-LAPW) method. Structural ground state parameters were optimized, and the structural stability of these materials was assessed by evaluating their formation energy, phonon frequencies, and tolerance factor. Analysis of the electronic structure reveals that Na2AgAsX6 exhibit an indirect gap character, with energy values of 2.0 (for Cl) and 1.29 eV (for Br). Additionally, we computed various optical properties including dielectric functions (ε1, ε2), absorption coefficient (α), refractive index (n), extinction coefficient (k), and reflectivity (R), demonstrating a broad absorption spectrum spanning from visible to ultraviolet wavelengths. Furthermore, the investigation extends to determine the electronic transport properties—Seebeck coefficient (S), electrical conductivity (σ/τ), power factor (PF), thermal conductivity (κe/τ), and figure of merit (ZT) for Na2AgAsX6 (X = Cl, Br), using BoltzTraP code. These findings underscore the substantial potential of Na2AgAsX6 (X = Cl, Br) halide perovskites as efficient light absorption layers in the development of high-performance perovskite solar cells (PCSs) and also hold promise for future eco-friendly thermoelectric generator applications.

A signal polarity conversion photoelectrochemical immunosensor for neuron-specific enolase detection based on MgIn2S4-sensitized CsPbBr3.

Aphotoelectrochemical (PEC) immunosensor was designed based on MgIn2S4-decorated inorganic halide perovskite CsPbBr3 combined with the signal polarity conversion strategy for neuron-specific enolase (NSE) detection. CsPbBr3 was applied as the basic photoactive material owing to its excellent optical and electronic properties, which provide a good PEC performance for sensor construction. In order to improve the stability of this perovskite, the three-dimensional flower-like MgIn2S4 with a desirable direct band gap was applied to enhance the PEC response. Also, the excellent structure of MgIn2S4 provides large surface-active sites for CsPbBr3 loaded. For enhancing the detection sensitivity of PEC immunosensor, p-type CuInS2 was used as a signal probe which fixed on detection antibody (Ab2). When the target NSE was present, the photogenerated electrons produced by CuInS2 were transferred to the test solution, and the polarity of PEC signal changes. Based on the above photosensitive materials and signal conversion strategy, the proposed PEC immunosensor showed favorable detection performance, and the lineardetection range is 0.0001 ~ 100ng/mL with a 38fg/mL of detection limit. The proposed strategy improved the adhibition of CsPbBr3 in the analytical chemistry field as well as provided a reference method for other protein detections.

Investigation strain effects on the electronic, optical, and output performance of the novel inorganic halide perovskite Sr3SbI3 solar cell

Inorganic perovskite materials have drawn more interest in solar technology because of their outstanding structural, optical, and electrical features. Utilizing first-principles density-functional theory, this work sought to determine how compressive and tensile strain affected the structural, optical, and electrical properties of Sr3SbI3, an inorganic cubic perovskite (FP-DFT). A direct bandgap of 1.307/1.95 eV was detected with PBE/HSE method at the point in the unstrained planar Sr3SbI3 molecule. But when the relativistic spin-orbital coupling (SOC) effect was taken into consideration, the bandgap of Sr3SbI3 perovskite dropped to 0.862 eV Additionally, the structure's bandgap showed a tendency to decrease under compressive pressure and slightly increase under tensile strain. According to the optical parameters, including dielectric functions, absorption coefficient, reflectivity, and electron loss functions, the band characteristics suggested that the material had substantial absorption capabilities in the visible area. The dielectric constant spikes of Sr3SbI3 moved towards lower photon energy (redshift) during compressive strain, however, the material showed an increase in photon energy changing behavior under tensile strain (blueshift). Finally, the photovoltaic (PV) performance of novel Sr3SbI3 absorber-based cell structures with SnS2 as Electron Transport Layer (ETL) was systematically investigated at varying compressive and tensile strain using SCAPS-1D simulator. The maximum power conversion efficiency (PCE) was found 29.91 % with JSC of 46.22 mA/cm2, FF of 79.50 %, VOC of 0.8139 V for maximum 4 % compressive strain. Therefore, the strain-dependent electronic and optical properties of Sr3SbI3 studied here would facilitate its future use in the design of photovoltaic cells and optoelectronics.

Discovery of Rb-based auric–aurous halide perovskites as promising narrow bandgap semiconductors for energy conversion applications

Inorganic gold halide perovskites, owing to their excellent stability and tunable bandgaps, are poised to serve as environmentally benign alternatives to lead halide perovskites in the field of energy conversion applications.

Investigating Pressure-Driven Semiconductor-to-Metal Transition in Lead-Free Perovskites AlGeX3 (X= F, Cl, and Br): Insights from First-Principles Calculations

In the pursuit of commercializing electronic and optoelectronic devices, researchers have turned their attention to non-toxic inorganic cubic metal halide perovskites. This study focuses on novel lead-free compounds—specifically AlGeX3 (where...

Doping strategies for inorganic lead-free halide perovskite solar cells: progress and challenges.

In recent years, remarkable advancements have been achieved in the field of halide perovskite solar cells (PSCs). However, the commercialization of PSCs has been impeded by challenges such as Pb leakage and the instability of hybrid organic-inorganic perovskites (HOIPs). Hence, the future lies in the development of environmentally friendly inorganic lead-free halide perovskites (LFHPs) based on elements like Sn, Ge, Bi, Sb, and Cu, which show great promise for photovoltaic applications. However, LFHP photovoltaic cells still face challenges such as low efficiency, poor film quality, and stability in comparison to HOIPs. These limitations significantly hinder their further development. To address these issues, element doping strategies, including cationic and anionic doping, as well as the use of additives, are frequently employed. These strategies aim to improve film quality, passivate defects, reduce the band gap, and enhance device performance and stability. In this paper, we aim to provide a comprehensive review of the recent research progress in doping strategies for LFHPs.

Crystallization kinetic engineering for growth of thin metal halide perovskite platelets

Thin Cs2AgBiBr6 platelets possessing optimized optical and photo-response properties are obtained via a crystallization kinetic regulation strategy.

Pressure enables high-standard white light emission and significant emission enhancement in a 2D halide perovskite

A 2D OIHP, (CHA)2PbBr4, exhibits significant pressure-induced emission enhancement at 2.0 GPa. The luminescence color of the crystal changes from yellow to white under pressure.

A layering technique for achieving pinhole-free organic–inorganic halide perovskite thin films through the vapor–solid reaction

A multi-stage vapor–solid reaction technique was introduced to form segmented perovskite thin films. The triple-layer film exhibited a dense, pinhole-free structure. Solar cells made from it achieved a champion power conversion efficiency of 21.09%.