One-dimensional Perovskite Research Articles

In-Situ Growth of One-Dimensional Blocking Layer to Mitigate Deficient Surface of Single-Crystal Perovskites.

Organic-inorganic halide perovskite (OIHP) single crystals are promising for optoelectronic application, but their high surface trap density and associated ion migration hinders device performance and stability. Herein, a one-dimensional (1D) perovskites are designed and proposed as blocking layer at the crystal/electrode interface to mitigate the surface issues. As a model system, the interface ion migration in Cs0.05FA0.95PbI3 (FA=formamidinium) single-crystal perovskite solar cells (PSCs) is obviously suppressed, leading to increase of T90 lifetime from 260 to 1000 hours, five times better than previously reported results. Besides, the reduction of surface iodide ion vacancies inhibits nonradiative recombination, thus increasing the efficiency from 22.1 % to 23.8 %, which is one of the highest values for single-crystal PSCs. Since the deficient crystal surface is a universal and open issue, our strategy is instructive for optimizing diverse single-crystal perovskite devices.

Ultrafast Interfacial Charge Transfer in Anisotropic One-Dimensional CsPbBr3/Pt Epitaxial Heterostructure.

Colloidal one-dimensional (1D) perovskite nanorods (NRs) and metal epitaxial heterostructures (HSs) are the promising class of new materials for efficient photovoltaic and photocatalytic applications. Besides, fundamental photophysical properties and its device applications of 1D perovskite-metal HSs are limited due to their challenging synthetic protocols and difficulties in forming epitaxial growth between covalent and ionic bonds. Herein, we have synthesized the CsPbBr3 perovskite NRs-platinum (Pt) nanoparticles (NPs) (CsPbBr3/Pt) epitaxial HS using cation exchange followed by chemical reduction methods with the orthorhombic Cs2CuBr4 NRs. Here, the tertiary ammonium ions extensively helped to form the 1D Cs2CuBr4, CsPbBr3 NRs, and CsPbBr3/Pt HSs. For CsPbBr3/Pt HSs an epitaxial relationship has been established in the (020) plane of orthorhombic CsPbBr3 with the (020) plane of cubic Pt. Further, femtosecond transient absorption (TA) spectroscopy was employed to study the charge carrier dynamics of CsPbBr3/Pt HS. Upon 420 nm photoexcitation, excitons in the conduction band of CsPbBr3 NRs dissociate by electron transfer (with an ultrafast time of 1.1 ps) to the Pt domain. In addition, charge transfer (CT) was also demonstrated in the CsPbBr3/Pt HS, which is ascribed to strong electron coupling and epitaxial growth between CsPbBr3 and Pt states. This extensive understanding of the electron transfer dynamics of CsPbBr3/Pt epitaxial HS may pave the way to designing highly efficient photovoltaic and photocatalytic applications.

Conjugated diamine cation based halide perovskitoid enables robust stability and high photodetector performance

Low-dimensional lead halide materials have proved to be intrinsically stable semiconductor materials. However, the development of one-dimensional (1D) perovskites or perovskitoids with both robust water stability and high optoelectronic performance still faces significant challenges. Here, we report a new class of 1D (TzBIPY)Pb2X6 (X = Cl, Br, I) perovskitoids featuring a π-conjugated diamine cation (TzBIPY = 2,5-di(pyridin-4-yl)thiazolo[5,4-d]thiazole). The TzBIPY2+ cation with delocalized electrons directly contributes to the electronic structure and hence reduces the band gap. Especially, the Br-based material exhibits enhanced carrier separation and transport capacity, benefiting from the improved electronic conjugation together with a type II intramolecular heterojunction between conjugated organic cations and Pb–X octahedra. The (TzBIPY)Pb2Br6 photodetector exhibits an impressive photocurrent on/off ratio of 8.1 × 105, which is much superior to the previous three-dimensional (3D) perovskite benchmark. Additionally, the π-conjugated cations serve as dense protective shields for vulnerable Pb–X inorganic lattice against being attacked by water, thus demonstrating exceptional stability even immersed in water for over 3000 h.

Pressure-induced abnormal blue-shift emission enhancement and phase transition of perovskite DMAPbI3

Designing low-dimensional hybrid organic–inorganic perovskites (HOIPs) with enhanced broadband emission under ambient conditions remains a pressing challenge. Here, interesting results of emission blueshift and enhancement were successfully achieved by pressure modulation of the (NH2(CH3)2PbI3 ((NH2(CH3)2 = DMA) structure. The observed rapid blueshifted emission is closely related to the distortion of PbI6 octahedron induced by phase transition from the P63/mc phase to the P1 phase at 0.8 GPa, which has been confirmed by in situ high-pressure PL, UV–vis absorption, synchrotron XRD and Raman spectroscopy. The pressure-induced PL enhancement of DMAPbI3 can be ascribed to the mechanism that the distorted PbI6 octahedrons promote the radiative recombination of self-trapped excitons by increasing the activation barrier energy for detrapping. The PL intensity enhancement was retained at 4 times the initial value after the pressure was released. These findings deepen the understanding of the structure-property relationships of one-dimensional perovskite and reveal the roles of pressure in regulating the optical properties of perovskites.

(Invited) Phase Engineering for Enhanced Stability of Perovskite Nanowire Optoelectronics

The crystallization of halide perovskites (HPs) into one-dimensional structures has generated considerable research interest for their promising prospects in studying electron transport characteristics and multifunctional nanoscale devices. Various strategies have been developed to achieve in-plane growth of one-dimensional (1D) structures, including epitaxy, capillary-bridge-manipulated graphoepitaxy, and van der Waals epitaxy. Typically, the VLS growth mode, which involves the initial seeding of metallic catalytic nanoparticles to facilitate the process, has realized the out-of-plane and bottom-up synthesis route, opening up a new pathway for the one-dimensional perovskite electronics and optoelectronics.Among many recent advances, Zinc (Zn) has become a significant suppressor of vacancy formation in halide perovskites, establishing its pivotal role in defect engineering for these materials. Herein, we report the Zn-catalyzed vapor-liquid-solid (VLS) route to render black-phase CsPbI3 nanowires operationally stable at room temperature. Based on first-principle calculations, the doped Zn2+ can not only lead to the partial crystal lattice distortion but also reduce the formation energy value from the black phase to the yellow phase, improving the stability of the desired black phase. A series of contrast tests further confirm the stabilization effect of the Zn-doped strategy. Besides, the polarization-sensitive characteristics of black phase CsPbI3 nanowires were revealed. Our work highlights the importance of phase stabilization engineering for CsPbI3 nanowires and their potential applications in anisotropic optoelectronics.

Narrow Bandgap 1D Lead Iodide Perovskite with Aminophenyl Viologen.

One-dimensional (1D) perovskites (perovskitoids) occupy an important place among modern semiconducting materials, offering design flexibility together with a wide range of properties. However, most such materials have a large bandgap, which limits their application in photovoltaics. Here, we present a new 1D hybrid perovskite containing the functional cation aminophenyl viologen (APhV). Similar to other materials from the viologen perovskite family, aminophenyl viologen iodidoplumbate(II) (APhV[Pb2I6]·2NMP) exhibits a broad absorption with a narrow and direct bandgap of 1.66 eV, which was calculated from the experimental data and is supported also by our first-principles simulations. Close contact between electron-rich inorganic chains and electron-accepting viologen molecules suggests charge transfer within the hybrid, which is also visible in the density of states. Considering its reasonable thermal stability, aminophenyl viologen iodidoplumbate can find a wide application in photovoltaics.

Eliminating Hole Extraction Barrier in 1D/3D Perovskite Heterojunction for Efficient and Stable Carbon-Based CsPbI3 Solar Cells with a Record Efficiency.

Carbon-based perovskite solar cells (C-PSCs) have the advantages of low-cost and high-stability, but their photovoltaic performance is limited by severe defect-induced recombination and low hole extraction efficiency. 1D perovskite is proven to effectively passivate the defects on the perovskite surface, therefore reducing non-radiative recombination loss. However, the unsuitable energy level of most 1D perovskite renders an undesired downward band bending for 3D perovskite, resulting in a high hole extraction barrier and reduced hole extraction efficiency. Therefore, rational design and selection of 1D perovskites as the modifiers are essential in balancing defect passivation and hole extraction. In this work, based on simulation calculations, thiocholine iodide (TchI) is selected to prepare 1D perovskite with high work function and then constructs TchPbI3/CsPbI3 1D/3D perovskite heterojunction. Experimental results show that this strategy eliminates the hole extraction barrier at the perovskite/carbon interface, which improves the hole extraction efficiency of corresponding devices. Meanwhile, the strong interaction between the thiol group and Pb suppresses defect-induced recombination effectively and improves the stability of CsPbI3. The assembled C-PSCs exhibit a champion efficiency of 19.08% and a certified efficiency of 18.7%. To the best of the knowledge, this is a new efficiency record for inorganic C-PSCs.

Pyridine substitution strategy for one-dimensional perovskite: Toward efficient and stable mixed-dimensional photovoltaics

Surface passivation via one-dimensional (1D) perovskite has emerged as a promising method to suppress trap states and enhance charge extraction and transportation, leading to improved efficiency and long-term stability. Ionic liquid engineering, characterized as environmental-green additive, has shown particular promise in this regard. Herein, we explore the influence of the electronegativity and dipole moment of two different ionic liquids, benzamidine hydrochloride (BZ) and 2-amidinopyridine hydrochloride (2AP), on the formation of 1D perovskite and the performance of resulting devices. An effective passivation 1D layer has been formed through post-treatment, resulting in nano-rod crystal modified morphology with effectively passivated defects at grain boundaries, enhanced hydrophobicity, prolonged charge carrier lifetime, tailored energy level, and decreased trap density. Notably, the perovskite film treated with 2AP exhibited superior performance due to its stronger interaction with 3D perovskite and better passivation ability on defects originating from the presence of a pyridine ring. As a result, the PSCs incorporating 2AP achieved a champion power conversion efficiency of 24.55 % and retain 90 % of their initial efficiency after storage for over 1000 h at room temperature under ∼ 50 % RH conditions without encapsulation. This study provides valuable insights for expanding the selection of ionic liquids applied in 1D perovskite-assisted surface passivation towards efficient and stable photovoltaics.

Three-State Dielectric Switching within a Narrow Temperature Range in Isopropylammonium Lead Iodide, a One-Dimensional Perovskite with Polar Phase.

The phenomenon of dielectric switching has garnered considerable attention due to its potential applications in electronic and photonic devices. Typically, hybrid organic-inorganic perovskites, HOIPs, exhibit a binary (low-high) dielectric state transition, which, while useful, represents only the tip of the iceberg in terms of functional relevance. One way to boost the versatility of applications is the discovery of materials capable of nonbinary switching schemes, such as three-state dielectric switching. The ideal candidate for that task would exhibit a trio of attributes: two reversible, first-order phase transitions across three distinct crystal phases, minimal thermal hysteresis, and pronounced, step-like variations in dielectric permittivity, with a substantial change in its real part. Here, we demonstrate a one-dimensional lead halide perovskite with the formula (CH3)2C(H)NH3)PbI3, abbreviated as ISOPrPbI3, that fulfills these criteria and demonstrates three-state dielectric switching within a narrow temperature range of ca. 45 K. Studies on ISOPrPbI3 also revealed the polar nature of the low-temperature phase III below 266 K through pyrocurrent experiments, and the noncentrosymmetric character of the intermediate phase II and low-temperature phase III is confirmed via second harmonic generation measurements. Additionally, luminescence studies of ISOPrPbI3 have demonstrated combined broadband and narrow emission properties. The introduction of ISOPrPbI3 as a three-state dielectric switch not only addresses the limitations posed by the wide thermal gap between dielectric states in previous materials but also opens new avenues for the development of nonbinary dielectric switchable materials.

Dimensional Regulation from 1D/3D to 2D/3D of Perovskite Interfaces for Stable Inverted Perovskite Solar Cells.

Constructing low-dimensional/three-dimensional (LD/3D) perovskite solar cells can improve efficiency and stability. However, the design and selection of LD perovskite capping materials are incredibly scarce for inverted perovskite solar cells (PSCs) because LD perovskite capping layers often favor hole extraction and impede electron extraction. Here, we develop a facile and effective strategy to modify the perovskite surface by passivating the surface defects and modulating surface electrical properties by incorporating morpholine hydriodide (MORI) and thiomorpholine hydriodide (SMORI) on the perovskite surface. Compared with the PI treatment that we previously developed, the one-dimensional (1D) perovskite capping layer derived from PI is transformed into a two-dimensional (2D) perovskite capping layer (with MORI or SMORI), achieving dimension regulation. It is shown that the 2D SMORI perovskite capping layer induces more robust surface passivation and stronger n-N homotype 2D/3D heterojunctions, achieving a p-i-n inverted solar cell with an efficiency of 24.55%, which retains 87.6% of its initial efficiency after 1500 h of operation at the maximum power point (MPP). Furthermore, 5 × 5 cm2 perovskite mini-modules are presented, achieving an active-area efficiency of 22.28%. In addition, the quantum well structure in the 2D perovskite capping layer increases the moisture resistance, suppresses ion migration, and improves PSCs' structural and environmental stability.

Cation-π interactions enabled water-stable perovskite X-ray flat mini-panel imager

Sensitive and stable perovskite X-ray detectors are attractive in low-dosage medical examinations. The high sensitivity, tunable chemical compositions, electronic dimensions, and low-cost raw materials make perovskites promising next-generation semiconductors. However, their ionic nature brings serious concerns about their chemical and water stability, limiting their applications in well-established technologies like crystal polishing, micro-processing, photolithography, etc. Herein we report a one-dimensional tryptamine lead iodide perovskite, which is stable in water for several months as the strong cation-π interactions between organic cations. The one-dimensional and two-dimensional tryptamine lead iodide perovskite tablets are switchable through thermal-annealing or water-soaking treatments to relax microstrains. The water-stable and microstrain-free one-dimensional perovskite tablets yield a large sensitivity of 2.5 × 106 μC Gyair−1 cm−2 with the lowest detectable dose rate of 5 nGyair s−1. Microelectrode arrays are realized by surface photolithography to construct high-performance X-ray flat mini-panels with good X-ray imaging capability, and a record spatial resolution of 17.2 lp mm−1 is demonstrated.

Stability-enhanced perovskite heterointerfaces and solar cells via strongly anchored and sterically hindered ligands

The inherent dynamic behavior observed in 2D‐3D interfaces in perovskite solar cells (PSC), driven by ion diffusion and migration, poses a significant challenge in establishing a stable passivation and barrier interface that can fulfill the device's complete lifecycle requirements. In this work, we construct large sterically hindered one-dimensional (1D) perovskite crystals integrated with the perovskite surface and observed their evolution during accelerated aging for the first time. The results show that this strong interfacial bonding not only effectively passivates surface defects but also prevents interface reconstruction due to migration, even under elevated temperatures. Moreover, it serving as an effective barrier can significantly suppress the interdiffusion between the copper electrode and the perovskite layer. Resultantly, our approach attained a remarkable efficiency of 23.3% via a scalable coating process in FA0.3MA0.7PbI3 PSC device. Notably, these devices exhibited significantly enhanced operational stability (T95 ≈1200 h, 55 ± 5 °C) and thermal stability (T90 ≈700 h, 85 °C).

Dimension-Dependent Phase Transitions, Ferroelasticity, and Photoluminescence in Hybrid Organic-Inorganic Materials.

[(CH3)3P(CH2)2OH]2Cd3(SCN)8 (1) and [(CH3)3P(CH2)2OH]Cd(SCN)3 (2) were obtained with completely different structures and properties under the same synthesis conditions. Compound 1, showing green fluorescence, has a rare three-dimensional 4,6-connected fsh topology having (43.63)2(46.66.83) Schläfli notation, while compound 2 with blue-violet phosphorescence displays a one-dimensional perovskite structure with an infinite {[Cd(SCN)3]-}∞ chain and exhibits both ferroelastic and dielectric switching characteristics.

Unraveling the Ultrafast Coherent Dynamics of Exciton Polariton Propagation at Room Temperature.

Exciton polaritons are widely considered as promising platforms for developing room-temperature polaritonic devices, owing to the high-speed propagation and nonlinear interactions. However, it remains challenging to explore the dynamics of exciton polaritons specifically at room temperature, where the lifetime could be as small as a few picoseconds and the prevailing time-averaged measurement cannot give access to the true nature of it. Herein, by using the time-resolved photoluminescence, we have successfully traced the ultrafast coherent dynamics of a moving exciton polariton condensate in a one-dimensional perovskite microcavity. The propagation speed is directly measured to be ∼12.2 ± 0.8 μm/ps. Moreover, we have developed a time-resolved Michelson interferometry to quantify the time-dependent phase coherence, which reveals that the actual coherence time of exciton polaritons could be much longer (nearly 100%) than what was believed before. Our work sheds new light on the ultrafast coherent propagation of exciton polaritons at room temperature.

Perovskite grain wrapping by converting interfaces and grain boundaries into robust and water-insoluble low-dimensional perovskites.

Stabilizing perovskite solar cells requires consideration of all defective sites in the devices. Substantial efforts have been devoted to interfaces, while stabilization of grain boundaries received less attention. Here, we report on a molecule tributyl(methyl)phosphonium iodide (TPI), which can convert perovskite into a wide bandgap one-dimensional (1D) perovskite that is mechanically robust and water insoluble. Mixing TPI with perovskite precursor results in a wrapping of perovskite grains with both grain surfaces and grain boundaries converted into several nanometer-thick 1D perovskites during the grain formation process as observed by direct mapping. The grain wrapping passivates the grain boundaries, enhances their resistance to moisture, and reduces the iodine released during light soaking. The perovskite films with wrapped grains are more stable under heat and light. The best device with wrapped grains maintained 92.2% of its highest efficiency after light soaking under 1-sun illumination for 1900 hours at 55°C open-circuit condition.

High grain boundary recombination velocity in polycrystalline metal halide perovskites.

Understanding carrier recombination processes in metal halide perovskites is fundamentally important to further improving the efficiency of perovskite solar cells, yet the accurate recombination velocity at grain boundaries (GBs) has not been determined. Here, we report the determination of carrier recombination velocities at GBs (SGB) of polycrystalline perovskites by mapping the transient photoluminescence pattern change induced by the nonradiative recombination of carriers at GBs. Charge recombination at GBs is revealed to be even stronger than at surfaces of unpassivated films, with average SGB reaching 2200 to 3300 cm/s. Regular surface treatments do not passivate GBs because of the absence of contact at GBs. We find a surface treatment using tributyl(methyl)phosphonium dimethyl phosphate that can penetrate into GBs by partially dissolving GBs and converting it into one-dimensional perovskites. It reduces the average SGB by four times, with the lowest SGB of 410 cm/s, which is comparable to surface recombination velocities after passivation.

Homochiral Hybrid Organic-Inorganic Cadmium Chlorides Directed by Enantiopure Amino Acids.

Homochiral cadmium chlorides were prepared under mild conditions using enantiopure amino acids as structure-directing agents. They feature a lacunary hexagonal CdCl2 lattice as well as a one-dimensional perovskite structure. The coexistence of protonated and zwitterionic amino acids between cadmium chloride chains is quite rare. These compounds are nonlinear optically active solids showing a moderate second-harmonic-generation response. Theoretical calculations were performed to reveal the origin of their nonlinear-optical properties.

Temperature-Dependent Luminescence and Anisotropic Optical Properties of Centimeter-Sized One-Dimensional Perovskite Trimethylammonium Lead Iodide Single Crystals.

Low-dimensional hybrid halide perovskite materials with self-trapped exciton (STE) emissions and anisotropic properties are highly attractive for their great potential in many applications. However, to date, reports on large one-dimensional (1D) perovskite single crystals have been limited. Here, centimeter-sized 1D single crystals of trimethylammonium lead iodide (TMAPbI3) with typical STE emission are synthesized by an antisolvent vapor-assisted crystallization method. Thermal quenching and antiquenching with a high relative sensitivity of photoluminescence (PL) are observed and studied via temperature-dependent photoluminescence spectroscopy. Further analysis indicates that the temperature-dependent PL behaviors are influenced by the self-trapping of the free exciton and the migrations between self-trapped excitons and intermediate nonradiative states. The TMAPbI3 single crystal also exhibits a linearly polarized emission and a large birefringence that is higher than those of commercial birefringent crystals. This 1D perovskite with high structural anisotropy has promise for applications in versatile optical- and luminescence-related fields.

A one-dimensional perovskite with ferroelectric and switchable nonlinear optical properties: [azetidinium]CdCl3

A new ferroelectric 1-D perovskite (C3H8N)[CdCl3] was synthesized and characterized.

Multi-functional hybrid perovskites with triple-channel switches and optical properties

Triple-channel (dielectric/SHG/PL) switches with a one-dimensional perovskite structure are successfully obtained through the halogen substitution strategy. This work might inspire the further exploration of multi-functional switching materials.