Organic-inorganic Hybrid Perovskite Research Articles

Prediction of Organic-Inorganic Hybrid Perovskite Band Gap by Multiple Machine Learning Algorithms.

As an indicator of the optical characteristics of perovskite materials, the band gap is a crucial parameter that impacts the functionality of a wide range of optoelectronic devices. Obtaining the band gap of a material via a labor-intensive, time-consuming, and inefficient high-throughput calculation based on first principles is possible. However, it does not yield the most accurate results. Machine learning techniques emerge as a viable and effective substitute for conventional approaches in band gap prediction. This paper collected 201 pieces of data through the literature and open-source databases. By separating the features related to bits A, B, and X, a dataset of 1208 pieces of data containing 30 feature descriptors was established. The dataset underwent preprocessing, and the Pearson correlation coefficient method was employed to eliminate non-essential features as a subset of features. The band gap was predicted using the GBR algorithm, the random forest algorithm, the LightGBM algorithm, and the XGBoost algorithm, in that order, to construct a prediction model for organic-inorganic hybrid perovskites. The outcomes demonstrate that the XGBoost algorithm yielded an MAE value of 0.0901, an MSE value of 0.0173, and an R2 value of 0.991310. These values suggest that, compared to the other two models, the XGBoost model exhibits the lowest prediction error, suggesting that the input features may better fit the prediction model. Finally, analysis of the XGBoost-based prediction model's prediction results using the SHAP model interpretation method reveals that the occupancy rate of the A-position ion has the greatest impact on the prediction of the band gap and has an A-negative correlation with the prediction results of the band gap. The findings provide valuable insights into the relationship between the prediction of band gaps and significant characteristics of organic-inorganic hybrid perovskites.

Recent Advances in Room-Temperature Phosphorescence Metal-Organic Hybrids: Structures, Properties, and Applications.

Metal-organic hybrid (MOH) materials with room-temperature phosphorescence (RTP) have drawn attention in recent years due to their superior RTP properties of high phosphorescence efficiency and ultralong emission lifetime. Great achievement has been realized in developing MOH materials with high-performance RTP, but a systematic study on MOH materials with RTP feature is lacking. This review highlights recent advances in metal-organic hybrid RTP materials. The molecular packing, the photophysical properties, and their applications of metal-organic hybrid RTP materials are discussed in detail. Metal-organic hybrid RTP materials can be divided into six parts: coordination polymers, metal-organic frameworks (MOFs), metal-halide hybrids, organic ionic crystals, organic ionic polymers, and organic-inorganic hybrid perovskites. These RTP materials have been successfully applied in time-resolved data encryption, fingerprint recognition, information logic gates, X-ray imaging, and photomemory. This review not only provides the basic principles of designing RTP metal-organic hybrids, but also propounds the future research prospects of RTP metal-organic hybrids. This review offers many effective strategies for developing metal-organic hybrids with excellent RTP properties, thus satisfying practical applications.

Compositional Engineering of Hybrid Organic-Inorganic Lead-Halide Perovskite and PVDF-Graphene for High-Performance Triboelectric Nanogenerators.

Triboelectric nanogenerators (TENGs) have attracted a great deal of attention since they can convert ubiquitous mechanical energy into electrical energy and serve as a continuous power source for self-powered sensors. Optimization of the dielectric material composition is an effective way to improve the triboelectric output performance of TENGs. Herein, the hybrid organic-inorganic lead-iodide perovskite Cs0.05FA0.95-xMAxPbI3 was prepared by blade coating and used as a positive friction layer material. Moreover, PVDF-graphene (PG) nanofibers were prepared as negative friction layer materials by electrostatic spinning. The output performance of the TENG was enhanced by varying the MA content of the pervoskite films and the graphene content of the PG nanofibers. The champion output TENG based on Cs0.05FA0.9MA0.05PbI3/PG-0.15 achieved an open-circuit voltage of 245 V, a short-circuit current of 24 μA, and a charge transfer of 80.2 nC. Meanwhile, a maximum power density of 11.23 W m-2 was obtained at 100 MΩ. Moreover, the device exhibits excellent energy-harvesting properties, including excellent stability and durability, rapidly charges capacitors, and lights commercial LEDs and digital tubes.

The Modulation of the Optical Properties of Low‐Dimensional Hybrid Perovskite by Using Anchoring Groups and Biaxial Strain: A First‐Principles Study

AbstractIn this paper, using CsMA2Sn2I7 as an example, first‐principles calculations are performed to thoroughly investigate the crystal structures, electronic properties, and optical properties of 11 representative anchoring group/low‐dimensional hybrid perovskite systems. The results show that the addition of benzene, 4‐iodoaniline, aniline, and benzenethiol anchoring groups causes a blueshift phenomenon in the absorption spectra of CsMA2Sn2I7 perovskite. Furthermore, the involvement of the benzoic acid anchoring group has a minimal effect on the absorption spectra of the CsMA2Sn2I7 hybrid perovskites, which show better absorption intensity only in the ultraviolet. The addition of other anchoring groups leads to varying degrees of redshift in the absorption spectra of CsMA2Sn2I7 perovskite, which not only enhances absorption intensity but also lends to the improvement of the absorption efficiency in the visible range. In addition, the bandgap can be tuned by applying biaxial strain, which further effectively modulates the absorption intensity of the adsorption systems in different optical bands. Therefore, the selection of suitable anchoring groups has great potential for modulating the photovoltaic performance of organic–inorganic hybrid perovskites, which is helpful for the application of organic–inorganic perovskites in photovoltaics.

THz‐Wave Absorption Properties of Organic–Inorganic Hybrid Perovskite Materials: A New Candidate for THz Sensors

Over the past two decades, organic–inorganic hybrid perovskite materials (OHP) have been extensively explored across various scientific disciplines, including physics, chemistry, and materials science, with a primary focus on solar cells. Building on numerous studies, the development of OHP‐based solar cells has transitioned into practical product realization, instilling the anticipation of novel solar cell advancements. Notably, OHP demonstrates versatility beyond its conventional application in solar cell materials. The physical properties of OHP materials exhibit a unique signature, thereby underscoring their potential utility as innovative functional materials, encompassing light‐emitting diodes, lasers, and photodetectors. Recent reports on terahertz (THz)‐wave absorption properties of OHP materials indicate a high possibility of their potential application as THz sensors. From the viewpoint of medical devices, which hold the most promising application potential, the exploration of optical phonon vibrational modes in the 0.5–3 THz frequency range is important. Moreover, understanding the correlations between atomic structure and lattice vibration modes is indispensable. In this concise review, the THz‐wave absorption properties exhibited by 3D OHP materials are meticulously explored. Furthermore, future research directions for THz sensors using OHP materials are suggested.

In-Situ Polymer Framework Strategy Enabling Printable and Efficient Perovskite Solar Cells by Mitigating "Coffee Ring" Effect.

Organic-inorganic hybrid perovskites are considered ideal candidates for future photovoltaic applications due to their excellent photovoltaic properties. Although solution-printed manufacturing has shown inherent potential for the low-cost, high-throughput production of thin-film semiconductor electronics, the high-quality and high-reproducibility deposition of large-area perovskite remains a bottleneck that restricts their commercialization due to the droplet coffee-ring effect (CRE). In this study, these issues are addressed by introducing an in situ polymer framework. The 3D framework formed by spontaneous cross-linking improves the precursor viscosity and homogenizes its heat diffusion coefficient, counteracting the lateral capillary flow of the colloidal particles and anchoring their flocculent movement. Thus, the Marangoni convection intensity is properly controlled to ensure high-quality perovskite films, which significantly enhances reproducibility in printing efficient photovoltaics by mitigating the CRE. Subsequently, the perovskite solar cells and modules achieve power conversion efficiencies of 23.94 and 17.53%, and exhibit positive environmental stability, retaining over 90 and 78% efficiency after storage for 2500 and 1600h, respectively. This work may serves as a foundation for exploring precursor rheology to match the homogeneous deposition requirements of perovskite photovoltaics and facilitating the advancement of their printing manufacturing and commercialization transition.

Stable and Highly Efficient Photocatalysis with Two-Dimensional Organic-Inorganic Hybrid Perovskites.

Two-dimensional organic-inorganic hybrid perovskites (OIHPs) have excellent photoelectric properties, such as high charge mobility and a high optical absorption coefficient, which have attracted enormous attention in the field of optoelectronic devices and photochemistry. However, the stability of 2D OIHPs in solution is deficient. In particular, the lack of stability in polar solutions hinders their application in photochemistry. In this work, (iso-BA)2PbI4 was used as a model to explore the three possibilities of the stable existence of a 2D perovskite in aqueous solution. And two of these systems that stabilize the presence of (iso-BA)2PbI4 were further investigated through electrochemical testing. Moreover, (iso-BA)2PbI4 2D hybrid perovskites exhibited an outstanding degradation rate. The chiral perovskite (R/S-MBA)2PbI4 is able to degrade a 30 mg/L methyl orange solution completely within 5 min, making it one of the fastest catalysts for this particular organic reaction. Further, based on the electron spin resonance test, a degradation mechanism by the halide perovskite was proposed. Based on the great catalytic performance as well as good reusability and stability, (R/S-MBA)2PbI4 perovskites are expected to be a new generation of catalysts, making a great impact on the application of asymmetrically catalyzed photoreactions.

Ferroics in Hybrid Organic-Inorganic Perovskites: Fundamentals, Design Strategies, and Implementation.

Hybrid organic-inorganic perovskites (HOIPs) afford highly versatile structure design and lattice dimensionalities; thus, they are actively researched as material platforms for the tailoring of ferroic behaviors. Unlike single-phase organic or inorganic materials, the interlayer coupling between organic and inorganic components in HOIPs allows the modification of strain and symmetry by chirality transfer or lattice distortion, thereby enabling the coexistence of ferroic orders. This review focuses on the principles for engineering one or multiple ferroic orders in HOIPs, and the conditions for achieving multiferroicity and magnetoelectric properties. The prospects of multilevel ferroic modulation,chiral spin textures,and spin orbitronics in HOIPs are also presented.

A Different, Nondestructive Method of Investigating In Situ Degradation in Hybrid Perovskite Solar Cells

One of the most significant impediments to the upscaling of hybrid organic-inorganic perovskite (HOIP) solar cells is poor stability. So, to effectively establish precautionary strategies, it is necessary to have a comprehensive grasp of the mechanisms that contribute to their degradation. Conventional characterization techniques used for in situ degradation assessment of perovskite solar cells either track just universal parameters, which yields poor insights about localized degradation processes, or the technique itself induces degradation, which may confound results. Developed in this study is a nondestructive technique of analyzing in situ active layer degradation in HOIP solar cells’ active layer utilizing a combination of optical modelling and ageing device’s reflectance tracking. The optical dielectric functions of the solar cell’s functional layers were modelled using the layers’ transmitted and reflected light spectra. The transfer matrix approach was used to fit the reflectance spectrum of entire solar cell layer stacks utilizing the computed dielectric functions for individual materials and accounting for the possibility of lead iodide gradient layer formation in the model. Leveraging no other characterization method, the presence of a lead iodide gradient layer was identified within the solar cell layer stack, an unmistakable indicator of methyl ammonium lead iodide perovskite (MAPI) degradation, probing with only photons.

Inducing 2D Structure at Grain‐Boundary via Triazinane Molecular Modification to Improve Stability of Inverted Perovskite Solar Cells

Active layers of p–i–n organic–inorganic hybrid perovskite solar cells (PSCs) are passivated by star‐shape, multifunctional triazinane molecules, cyanuric acid (CA), and Tris(dibutylhydroxy‐ benzyl)isocyanuric acid (TPCA). The most interesting is that CA is used as a bulk additive is able to induce a two‐dimensional (2D) structure at grain boundaries (GBs) of the perovskite when excess PbI2 is present. TPCA is also important to use as a perovskite surface modifier and to reduce the defects in perovskite layer further. The reduced ideality factors, enhanced photoluminescence, and prolonged lifetimes all indicate suppression of non‐radiative recombination. The combination of the two substantially improves fill‐factors and open‐circuit voltages of the devices. This leads to markedly enhanced stabilities of the devices.

Atomic Structure and Dynamics of Organic-Inorganic Hybrid Perovskite Formamidinium Lead Iodide.

The atomic dynamic behaviors of formamidinium lead iodide [HC(NH2)2PbI3] are critical for understanding and improving photovoltaic performances. However, they remain unclear. Here, we investigate the structural phase transitions and the reorientation dynamics of the formamidinium cation [HC(NH2)2+, FA+] of FAPbI3 using neutron scattering techniques. Two structural phase transitions occur with decreasing temperature, from cubic to tetragonal phase at 285 K and then to another tetragonal at 140 K, accompanied by gradually frozen reorientation of FA cations. The nearly isotropic reorientation in the cubic phase is suppressed to reorientation motions involving a two-fold (C2) rotation along the N···N axis and a four-fold (C4) rotation along the C-H axis in the tetragonal phase, and eventually to local disordered motion as a partial C4 along the C-H axis in another tetragonal phase, thereby indicating an intimate interplay between lattice and orientation degrees of freedom in the hybrid perovskite materials. The present complete atomic structure and dynamics provide a solid standing point to understand and then improve photovoltaic properties of organic-inorganic hybrid perovskites in the future.

Ionizing Radiation Responsive Anomalous Photovoltage Drives Sensitive Self‐Powered X‐Ray Detection

AbstractThe anomalous photovoltaic (APV) effect in organic–inorganic hybrid perovskites (OIHPs) has attracted massive interest for developing high‐performance optoelectronic devices. However, exploring the ionizing radiation responsive APV effect remains blank, let alone its potential applications. Herein, the unprecedented APV behavior in a 1D lead‐free OIHP, (4‐AMP)BiI5 (ABI, 4‐AMP = 4‐(aminomethyl)pyridine) under X‐ray irradiation is reported, exhibiting a large above‐bandgap bulk photovoltage of ≈10 V. Such a strong APV effect is closely related to the intrinsic electric polarization in polar ABI, which acts as the driving force for X‐ray‐generated carriers’ separation and transport, thus allowing it to be self‐powered. As a result, sensitive self‐powered X‐ray detectors based on high‐quality ABI single crystals are successfully fabricated, possessing a high sensitivity of 66.84 µC Gy−1 cm−2, a low detection limit of 482 nGy s−1, and superior operational stability. This work first demonstrates the ionizing radiation‐responsive APV effect in OIHPs, which further enables passive radiation detection.

ZnO/SnO2 bilayer electron transport layer strategy to improve the performance of FAPbI3 solar cell

In recent years, organic–inorganic hybrid perovskite (PVK) devices have attracted widespread attention with their high absorption coefficient and low-cost fabrication process. Formamidinium lead iodide (FAPbI3) perovskite solar cells (PSCs) have been reported to obtain high power conversion efficiencies (PCEs) due to the narrow bandgap. Zinc oxide (ZnO) has better electrical conductivity and high transmittance than tin (IV) dioxide (SnO2). However, the deprotonation behavior of ZnO limits its use in formamidinium (FA) or methylammonium (MA) devices, so it is mostly used in all-inorganic PSCs. In this work, to avoid the deprotonation behavior of ZnO, we prepared FAPbI3 PSCs using ZnO/SnO2 as bilayer electron transporting layers (ETLs), which improved the conductivity of the ETLs and promoted electron extraction and transfer. In addition, the decrease in the oxygen vacancy (Ov) on the bilayer ETLs contributed to the suppression of the non-radiative recombination of the device, thus enabling the achievement of a higher fill factor. As a result, the modified ETLs increased the PCE of FAPbI3 PSCs from 20.24% to 21.42% and improved the stability of the devices. The PCE of unpackaged devices increased steadily to 21.91% when stored in an N2 atmosphere for 183 days.

Universal machine learning aided synthesis approach of two-dimensional perovskites in a typical laboratory

The past decade has witnessed the significant efforts in novel material discovery in the use of data-driven techniques, in particular, machine learning (ML). However, since it needs to consider the precursors, experimental conditions, and availability of reactants, material synthesis is generally much more complex than property and structure prediction, and very few computational predictions are experimentally realized. To solve these challenges, a universal framework that integrates high-throughput experiments, a priori knowledge of chemistry, and ML techniques such as subgroup discovery and support vector machine is proposed to guide the experimental synthesis of materials, which is capable of disclosing structure-property relationship hidden in high-throughput experiments and rapidly screening out materials with high synthesis feasibility from vast chemical space. Through application of our approach to challenging and consequential synthesis problem of 2D silver/bismuth organic-inorganic hybrid perovskites, we have increased the success rate of the synthesis feasibility by a factor of four relative to traditional approaches. This study provides a practical route for solving multidimensional chemical acceleration problems with small dataset from typical laboratory with limited experimental resources available.

Tunable Periodic Nanopillar Array for MAPbI3 Perovskite Photodetectors with Improved Light Absorption.

In the field of optoelectronic applications, the vigorous development of organic-inorganic hybrid perovskite materials, such as methylammonium lead triiodide (MAPbI3), has spurred continuous research on methods to enhance the photodetection performance. Periodic nanoarrays can effectively improve the light absorption of perovskite thin films. However, there are still challenges in fabricating tunable periodic patterned and large-area perovskite nanoarrays. In this study, we present a cost-effective and facile approach utilizing nanosphere lithography and dry etching techniques to create a large-area Si nanopillar array, which is employed for patterning MAPbI3 thin films. The scanning electron microscopy (SEM) and X-ray diffraction (XRD) results reveal that the introduction of nanopillar structures did not have a significant adverse effect on the crystallinity of the MAPbI3 thin film. Light absorption tests and optical simulations indicate that the nanopillar array enhances the light intensity within the perovskite films, leading to photodetectors with a responsivity of 11.2 A/W and a detectivity of 7.3 × 1010 Jones at 450 nm in wavelength. Compared with photodetectors without nanostructures, these photodetectors exhibit better visible light absorption. Finally, we demonstrate the application of these photodetector arrays in a prototype image sensor.

Mechanochemically-induced glass formation from two-dimensional hybrid organic-inorganic perovskites.

Hybrid organic-inorganic perovskites (HOIPs) occupy a prominent position in the field of materials chemistry due to their attractive optoelectronic properties. While extensive work has been done on the crystalline materials over the past decades, the newly reported glasses formed from HOIPs open up a new avenue for perovskite research with their unique structures and functionalities. Melt-quenching is the predominant route to glass formation; however, the absence of a stable liquid state prior to thermal decomposition precludes this method for most HOIPs. In this work, we describe the first mechanochemically-induced crystal-glass transformation of HOIPs as a rapid, green and efficient approach for producing glasses. The amorphous phase was formed from the crystalline phase within 10 minutes of ball-milling, and exhibited glass transition behaviour as evidenced by thermal analysis techniques. Time-resolved in situ ball-milling with synchrotron powder diffraction was employed to study the microstructural evolution of amorphisation, which showed that the crystallite size reaches a comminution limit before the amorphisation process is complete, indicating that energy may be further accumulated as crystal defects. Total scattering experiments revealed the limited short-range order of amorphous HOIPs, and their optical properties were studied by ultraviolet-visible (UV-vis) spectroscopy and photoluminescence (PL) spectroscopy.

Physical and chemical properties and degradation of MAPbBr3 films on transparent substrates.

To date, the potential exploitation of hybrid organic-inorganic perovskites (HOIPs) in photovoltaic technologies has been significantly hampered by their poor environmental stability. HOIP degradation can be triggered by conventional operational environments, with excessive heating and exposure to oxygen and moisture significantly reducing the performances of HOIP-based solar cells. An imperative need emerges for a thorough investigation on the impact of these factors on the HOIP stability. In this work, the degradation of methylammonium lead bromide (CH3NH3PbBr3) thin films, deposited via spin-coating on indium tin oxide (ITO) and strontium titanate (STO) substrates, was investigated by combining Raman and ultraviolet-visible (UV-Vis) absorption spectroscopy, as well as optical and fluorescence microscopy. We assessed the physical and chemical degradation of the films occurring under diverse preservation conditions, shedding light on the byproducts emerging from different degradation pathways and on the optimal HOIP preservation conditions.

Leveraging ordered voids in microporous perovskites for intercalation and post-synthetic modification.

We report the use of porous organic layers in two-dimensional hybrid organic-inorganic perovskites (HOIPs) to facilitate permanent small molecule intercalation and new post-synthetic modifications. While HOIPs are well-studied for a variety of optoelectronic applications, the ability to manipulate their structure after synthesis is another handle for control of physical properties and could even enable use in future applications. If designed properly, a porous interlayer could facilitate these post-synthetic transformations. We show that for a series of copper-halide perovskites, a crystalline arrangement of designer ammonium groups allows for permanently porous interlayer space to be accessed at room temperature. Intercalation of the electroactive molecules ferrocene and tetracyanoethylene into this void space can be performed with tunable loadings, and these intercalated perovskites are stable for months. The porosity also enables reactivity at the copper-halide layer, allowing for facile halide replacement. Through this, we access previously unobserved reactivity with halogens to perform halide substitution, and even replace halides with pseudohalides. In the latter case, the porous structure allows for stabilization of new phases, specifically a novel copper-thiocyanate perovskite phase, only accessible through post-synthetic modification. We envision that this broad design strategy can be expanded to other industrially relevant HOIPs to create a new class of highly adjustable perovskites.

A DFT study on CH3NH3MnBr3: a novel multiferroic organic–inorganic hybrid perovskite

Nowadays, ferroelectric organic–inorganic hybrid perovskite represents a crucial issue since it exhibits a huge potential to enhance solar cell efficiency significantly.

Stronger Polar Ferromagnetism and Narrower Optical Band Gaps in Two-Dimensional Hybrid Copper Perovskites Induced by Bromine-Substitution

Two-dimensional (2D) organic–inorganic hybrid perovskites are attracting great interest due to their structural tunability and rich functional characteristics. Here, we report a series 2D layered hybrid copper (II) halide perovskites...