Halide Perovskite Research Articles

Photoluminescence and Stability of Dion–Jacobson Tin-Based Halide Perovskites with Different Spacer Cation Chain Length

Two-dimensional tin halide perovskites are of significant interest for light emitting applications. Here, we investigate the effect of organic cation A on the stability of different Dion–Jacobson tin-based halide perovskites. The ASnBr4 materials using diammonium cation A with shorter alkyl chains are found to exhibit improved stability, exhibiting dramatic stability difference between the most stable HDASnBr4, where HDA denotes 1,6-hexanediammonium, and two materials with 8- and 10-carbon alkyl chain ammonium cations. The HDASnBr4 powders were thermally stable at 100 °C in an argon environment but exhibited decreasing photoluminescence with time in ambient air at 100 °C. The sample degradation at 100 °C is accelerated compared to room temperature, but it proceeds along similar pathways, namely phase transformation followed by perovskite decomposition. Light emission from HDASnBr4 thin films could be further enhanced by methanol vapor treatment, and warm white emission with Commission Internationale de l’Eclairage (CIE) coordinates (0.37, 0.34) could be obtained by combining HDASnBr4 with a blue-emitting polymer film, while direct mixing of blue phosphor and HDASnBr4 powder yields white emission with CIE coordinates of (0.34, 0.32).

Ion-Gel Gated Perovskite Field-Effect Transistors with Low Power Consumption and High Stability for Neuromorphic Applications.

Ruddlesden-Popper (RP) tin halide perovskites (THPs), exemplified by PEA2SnI4, are promising two-dimensional semiconductors for optoelectronic applications, yet their field-effect transistors (FETs) often suffer from high operating voltages and stability issues. Addressing these challenges, we developed a novel approach for integrating ion gel dielectrics composed of PVDF-HFP and [EMIM+][TFSI-] with PEA2SnI4, achieving FETs with record-low operating voltages as low as 2 V. Additionally, by substituting PEA+ with BA+ in BA2SnI4 FETs, we achieve enhanced device stability, with these devices exhibiting prolonged functionality exceeding 100 days. Uniform performance was also observed across 30 randomly tested devices fabricated on a 2 inch silicon wafer. These FETs also demonstrated synaptic behavior with ultralow energy consumption (5 × 10-11 J per operation). Leveraging these advancements, we constructed artificial neural networks for item classification, achieving high accuracy (97%). Moreover, the energy consumption for a single training process based on ion-gel gated BA2SnI4 FETs is approximately 2 orders of magnitude lower than that of similar networks based on the NVIDIA GeForce RTX 4060 GPU. Our results highlight the potential of ion-gel gated BA2SnI4 FETs for low-power, high-stability applications, paving the way for the next generation of perovskite-based electronic and neuromorphic devices.

Ambient Stable CsCu2I3 Flexible Gas Sensors for Reliable NO2 Detection at Room Temperature.

The advancement of the Internet of Things and artificial intelligence has increased the demand for air quality monitoring to protect human health. Nitrogen dioxide (NO2), a hazardous pollutant, causes inflammatory responses, even at low concentrations, necessitating sensitive gas sensors. Although metal oxide semiconductor sensors are commonly used, their high-operating temperature and reliance on additional heaters limit miniaturization and increase power consumption. Here, a lead-free, transparent, and flexible CsCu2I3 halide perovskite gas sensor was developed, demonstrating high sensitivity (1509% to 5 ppm) and selectivity for NO2 detection at room temperature with full recovery. The sensor exhibited high stability in ambient air and high-humidity environments, which is not achievable with traditional halide perovskite sensors. First-principles density functional theory calculations revealed the mechanisms underlying its stability and sensitivity. This study highlights the potential of halide perovskites for low-power gas sensing at room temperature, addressing critical challenges for commercially viable wearable applications.

Optical time-lapsed in situ mechanochemical studies on metal halide perovskite systems.

Metal halide perovskites are attractive for optoelectronic applications, but the existing solution-based synthetic methods rely on hazardous solvents and lack reproducibility. To overcome these challenges, solvent-free mechanochemical synthesis of perovskites can be conducted, although traditional opaque ball milling equipment hinder real-time monitoring of the reaction progress. Herein, mechanochemistry was performed with time-lapsed in situ (TLIS) measurements to elucidate the optical properties during the synthesis. The TLIS spectrometer enabled real-time observation of the impact of varying the compositions on the absorption properties of formamidinium/methylammonium lead iodide (FAxMA1-xPbI3, x = 0 to 1) and facilitated optimization of the synthesis duration. Moreover, we can accelerate the evaluation and directly observe the effects of different synthetic strategies for enhancing the photoluminescence quantum yield and stability of the perovskites, providing near-infrared (NIR) emitting tin-based perovskites FASnIzBr3-z (where z = 0 to 3) with core-shell structures. Intriguingly, halide ion migration was deduced in lead-free double perovskites Cs2NayAg1-yBiCl6 (y = 0 to 1.0) at room temperature during aging after mechanochemical activation. Our work provides insights into the mechanochemistry of compounds with low thermodynamic barriers.

Photoluminescence lifetime of perovskites on modified substrates

Lead halide perovskites have gained attention for their potential in optoelectronic applications, including photovoltaics and light-emitting devices, due to their remarkable optical and electronic properties. However, performance of these materials is highly dependent on morphological properties of the underlying substrates. In this study, the effects of substrate modifications on the photoluminescence lifetimes of CsPbBr₃ perovskites deposited on TiO2 substrates that were annealed at various temperatures were investigated. TiO2 substrates were characterized using glancing-angle x-ray diffraction and spectroscopic ellipsometry to assess changes in crystallinity and surface roughness. Time-correlated single photon counting spectroscopy was employed to measure the photoluminescent lifetimes of the perovskites. Scanning electron microscopy and x-ray diffraction were used to determine morphology and crystallinity. Results show a clear relationship between substrate annealing temperature and the photoluminescent lifetime of perovskite microcrystals. Substrates annealed at temperatures below 300 °C exhibited increased surface roughness with increased annealing temperature (22.4 Ȧ at room temperature and 48.05 Ȧ at 300 °C) and correspondingly shorter photoluminescent lifetimes (3.5 ns at room temperature and 0.4 ns at 300 °C) suggesting more rapid charge carrier recombination. In contrast, substrates annealed at 350 °C exhibited the longest lifetimes at 4.19 ns indicating a decrease in trap-mediated nonradiative recombination. Substrates annealed at 400 °C showed a further increase in crystallinity but did not extend the lifetime beyond that seen at 350 °C, suggesting an optimal balance between surface roughness and crystallization. These findings provide insights into the role of morphological substrate modifications in optimizing the optoelectronic properties of perovskite materials.

Perovskite-driven solar C2 hydrocarbon synthesis from CO2

Abstract Photoelectrochemistry (PEC) presents a direct pathway to solar fuel synthesis by integrating light absorption and catalysis into compact electrodes. Yet, PEC hydrocarbon production remains elusive due to high catalytic overpotentials and insufficient semiconductor photovoltage. Here we demonstrate ethane and ethylene synthesis by interfacing lead halide perovskite photoabsorbers with suitable copper nanoflower electrocatalysts. The resulting perovskite photocathodes attain a 9.8% Faradaic yield towards C2 hydrocarbon production at 0 V against the reversible hydrogen electrode. The catalyst and perovskite geometric surface areas strongly influence C2 photocathode selectivity, which indicates a role of local current density in product distribution. The thermodynamic limitations of water oxidation are overcome by coupling the photocathodes to Si nanowire photoanodes for glycerol oxidation. These unassisted perovskite–silicon PEC devices attain partial C2 hydrocarbon photocurrent densities of 155 µA cm−2, 200-fold higher than conventional perovskite–BiVO4 artificial leaves for water and CO2 splitting. These insights establish perovskite semiconductors as a versatile platform towards PEC multicarbon synthesis.

One-step Centimeter-Scale Growth of Sub-100-nm Perovskite Single-Crystal Arrays in Ambient Air for Color Painting.

Halide perovskite single crystals have demonstrated enormous potential for next-generation integrated optoelectronic devices. However, there is a lack of a facile method to realize the controllable growth of large-scale, high-quality, and high-resolution perovskite single crystal arrays on diverse types of substrates, which hinders their application in practical scenarios. Here, a one-step wettability-guided blade coating approach is reported for the rapid in situ crystallization of large-scale, multicolor, and sub-100 nm perovskite single-crystal arrays in the ambient environment. By this strategy, the physical dimensions of perovskite single crystals can be precisely regulated from 90 to 260 nm, with a size variation coefficient < 10% and an area of over 900 mm2. All three typicalhalogen perovskites for multi-color luminescence, CsPbX3 (X = Cl, Br, I) and their mixtures (Cl/Br or Br/I systems), are appliable to this fabrication process through the demonstration of complex RGB patterns with remarkable photoluminescence properties. Moreover, various rigid substrates such as silicon oxide (SiO2), silicon (Si), and glass can also be used to construct the wettability-constrast templates where perovskite crystal nucleate and grow. After that, the perovskite single-crystal arrays or complex patterns can be transferred onto flexible substrates, for instance, COC. This method combines convenient solution processing with conventional photolithography to prepare the high-resolution, large-area, and superior-quality perovskite single crystal arrays in a high-throughput manner, showing great potential in the integration of perovskite nano-optoelectronic devices and chips.

Stimulated Exciton–Polariton Scattering in Hybrid Halide Perovskites

Stimulated Exciton–Polariton Scattering in Hybrid Halide Perovskites

MAPbX3 Perovskite Single Crystals for Advanced Optoelectronic Applications: Progress, Challenges, and Perspective.

Perovskite single crystals have garnered significant attention due to their impressive properties in optoelectronic applications, including long carrier diffusion lengths, low trap-state densities, and enhanced stability. Methylamino lead halide perovskite (MAPbX3, where X is a halogen such as Cl, Br, or I) is a notable example of a metal halide perovskite with desirable properties and ideal cubic perovskites with a tolerance factor between 0.9 and 1.0. MAPbX3 has adjustable bandgap, high thermal and chemical stability, and excellent light absorption capacity. Here the unique characteristics of MAPbX3, including molecular structure, optical absorption properties, and carrier transport of MAPbX3 single crystals are summarized. Universal growth technologies for MAPbX3 single crystals, including inverse temperature crystallization, anti-solvent evaporation crystallization, solvent evaporation method, and single-crystalline thin film, including epitaxial method and space limiting method, are briefly introduced. Additionally, a comprehensive review of MAPbX3 single crystals in various optoelectronic device applications, including photodetectors, X-ray detectors, light-emitting diodes, lasers, and solar cells is mainly discussed. Finally, the current challenges and future prospects of the large-scale preparation and growth of MAPbX3 single crystals are put forward. With the continuous progress of photoelectric technology, more innovative photoelectric applications in the future are expected to bring more convenience and progress.

A2AlInI6 (A = K, Rb, Cs) Double Perovskite Halides for Renewable Energy Applications: A DFT Study on Stability, Light Absorption, and Thermoelectric Performance

A2AlInI6 (A = K, Rb, Cs) Double Perovskite Halides for Renewable Energy Applications: A DFT Study on Stability, Light Absorption, and Thermoelectric Performance

Theoretical Design of 2D Hybrid Lead-Free Halide Perovskites for Photovoltaic Applications

Theoretical Design of 2D Hybrid Lead-Free Halide Perovskites for Photovoltaic Applications

Machine learning, theoretical exploration and device simulation of Cs2NaXCl6 (X = Bi, In, Sb, Sc) double halide perovskites with spatial applications

Machine learning, theoretical exploration and device simulation of Cs2NaXCl6 (X = Bi, In, Sb, Sc) double halide perovskites with spatial applications

Room-temperature continuous-wave pumped exciton polariton condensation in a perovskite microcavity.

Microcavity exciton polaritons (polaritons) as part-light part-matter quasiparticles garner considerable attention for Bose-Einstein condensation at elevated temperatures. Recently, halide perovskites have emerged as promising room-temperature polaritonic platforms because of their large exciton binding energies and superior optical properties. However, currently, inducing room-temperature nonequilibrium polariton condensation in perovskite microcavities requires optical pulsed excitations with high excitation densities. Here, we demonstrate continuous-wave optically pumped polariton condensation with an exceptionally low threshold of ~0.53 W cm-2 and a narrow linewidth of ~0.5 meV. Polariton condensation is unambiguously demonstrated by characterizing the nonlinear behavior and coherence properties. We also unveil the trapping potential landscape strategy to facilitate polariton relaxation and accumulation. Our findings lay the foundation for the next-generation energy-efficient polaritonic devices operating at room temperature.

Pulsed Laser Deposition of Halide Perovskites with over 10-Fold Enhanced Deposition Rates.

The potential of the vapor-phase deposition of metal halide perovskites (MHPs) for solar cells remains largely untapped, particularly in achieving rapid deposition rates. In this study, we employ in situ photoluminescence (PL) to monitor the growth dynamics of MHPs deposited via pulsed laser deposition (PLD), with rates ranging from 6 to 80 nm/min. Remarkably, the PL intensity evolution remains consistent across both low- and high-deposition rates, indicating that increased deposition rates do not significantly alter the fundamental mechanisms driving MHP formation via PLD. However, microstructural analysis and time-resolved microwave conductivity (TRMC) measurements reveal that increasing deposition rates lead to randomly oriented films on contact layers and reduced charge mobility compared with films grown at lower deposition rates. These findings emphasize the critical role of controlling initial nucleation and the value of in situ PL monitoring in optimizing the vapor-phase deposition of MHPs for enhanced photovoltaic performance at high deposition rates.

Recent Advances and Challenges in Metal Halide Perovskite Quantum Dot-Embedded Hydrogels for Biomedical Application

Metal halide perovskite quantum dots (MHP QDs), as a kind of fluorescent material, have attracted much attention due to their excellent photoluminescence (PL) quantum yield (QY), narrow full width at half maximum (FWHM), broad absorption, and tunable emission wavelength. However, the instability and biological incompatibility of MHP QDs greatly hinder their application in the field of biomedicine. Hydrogels are three-dimensional polymer networks that are widely used in biomedicine because of their high transparency and excellent biocompatibility. This review not only introduces the latest research progress in improving the mechanical and optical properties of hydrogels/MHP QDs but also combines it with the existing methods for enhancing the stability of MHP QDs in hydrogels, aiming to provide new ideas for researchers in material selection and methods for constructing MHP QD-embedded hydrogels. Finally, their application prospects and future challenges are introduced.

Temperature‐Responsive Photoluminescence of 1D Chiral Lead Halide Perovskites with Highly Anisotropic Second Harmonic Generation

Temperature‐Responsive Photoluminescence of <scp>1D</scp> Chiral Lead Halide Perovskites with Highly Anisotropic Second Harmonic Generation

Inhibiting ion migration in strontium-lead halide perovskite for pure-blue emission: a first-principle and experimental study.

Bromide-chloride mixed perovskites have garnered significant attention as a direct and efficient material for achieving pure-blue emission. However, the complex problem of halide migration in mixed halide perovskites presents a significant obstacle to achieving stable electroluminescence (EL) spectra. Here, we investigate the mechanism of partially replacing the B-site Pb2+ with the non-toxic Sr2+ to achieve pure-blue emission based on first principles. The ion mobility activation energy of Sr2+ is 1.23 eV, which is an order of magnitude greater than that of halogens. Meanwhile, the incorporation of Sr2+ triples the activation energy for halogen migration. Furthermore, the halide defect formation energy increases from 4.75 eV to 5.62 eV, thereby reducing ion migration channels. Transient absorption spectroscopy demonstrates that suppressing the ion mobility pathway and enhancing ion mobility activation energy promotes the perovskite film to exhibit excellent spectral stability under laser pumping. Our work provides insights for the development of highly stable and eco-friendly perovskite devices.

Oxygen Activation Biocatalytic Precipitation Strategy Based on a Bimetallic Single-Atom Catalyst for Photoelectrochemical Biosensing.

The traditional biocatalytic precipitation (BCP) strategy often required the participation of H2O2, but H2O2 had the problem of self-decomposition, which prevented its application in quantitative analysis. This work first found that a bimetallic single-atom catalyst (Co/Zn-N-C SAC) could effectively activate dissolved O2 to produce reactive oxygen species (ROS) due to its superior oxidase (OXD)-like activity. Experimental investigations demonstrated that Co/Zn-N-C SAC preferred to produce highly active hydroxyl radicals (•OH), which oxidized 3-amino-9-ethyl carbazole (AEC) to produce reddish-brown insoluble precipitates. Based on this property, a unique oxygen-activated photoelectrochemical (PEC) biosensor was developed for chloramphenicol (CAP) detection. Cesium platinum bromide nanocrystals (Cs2PtBr6 NCs) were a new type of halide perovskite with lead-free, narrow band gaps, and water-oxygen resistance. Cs2PtBr6 NCs showed excellent cathodal PEC performance without an exogenous coreactant and were first used for PEC detection. As a "proof-of-concept application", Co/Zn-N-C SAC was introduced onto the surface of Cs2PtBr6 NCs by using the CAP dual-aptamer sandwich strategy. Co/Zn-N-C SAC activated dissolved O2 to produce ROS, which oxidized AEC to produce precipitates, quenching the cathodal PEC signal of Cs2PtBr6 NCs for CAP detection. In summary, this work first used SAC to overcome the restriction of the traditional enzymatic BCP strategy requiring H2O2, improved the stability and accuracy of quantitative analysis, and also broadened the application range of coreactant-free perovskite-type PEC biosensors.

Noble Metal Coating on Perovskite Microcrystals for Robust and Plasmonic Lasing Applications

AbstractLead halide perovskites (LHP) are solution‐processable semiconductor materials with high optical gain and broad wavelength tunability, making them well‐suited for laser applications. Here, a solution‐based method for the 3D conformal coating of LHP microcrystals with noble metals is presented. A nanoscale metal coating layer is found to significantly enhance both laser performance and environmental stability. This enables gold‐coated CsPbBr3 microcrystals to be delivered into live cells, achieving single‐mode plasmonic lasing under optical pumping. Silver‐coated CsPbBr3 particles demonstrate stable plasmonic lasing in the air. This one‐pot synthesis method opens new possibilities for leveraging LHPs to implant micro‐laser sources into physical, biological, and industrial systems.

Investigating the effects of a high boiling point solvent in slot die-coated halide perovskite solar cells.

To commercialize perovskite solar cells and advance beyond lab-scale comparisons, understanding large-area film formation using slot-die coating is essential to improve film homogeneity. Adding high-boiling-point solvents like NMP to the perovskite ink extends film's processing window, but the effects of varying NMP levels on gas-quenched slot-die coatings remain unclear. This article examines how different NMP ratios impact film quality, showing that a moderate amount of NMP as a co-solvent reduces defects, as observed through photoluminescence, hyperspectral absorbance, and back-illuminated optical absorptions. However, the decreased vapor pressure with the addition of NMP impairs crystallization and film coverage, highlighting the need for balanced amounts. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis indicate that the most volatile option tested at DMF:NMP ratio of 8:1 yields the most homogeneous and compact films. Slot-die-coated devices fabricated with this optimized ratio were subsequently compared with using NMP as an additive to increase the volatility of the perovskite inks further. The additive method demonstrates improved performance and uniformity, suggesting that minimizing high-boiling-point solvents to maintain ink volatility supports effective large-area coatings and fabrication of perovskite solar cells. Furthermore, this article provides insights on important metrics to narrow down suitable perovskite inks for large-area coatings.