Inorganic Perovskite Materials Research Articles

Investigations of high-Performance Ultrasonic Transducers based on PMN-PT Single Crystals

Ultrasonic transducers for NDE applications are commonly based on Lead Zirconate Titanate or PZT, an inorganic compound and ceramic perovskite material. Until now the advantages of PMN-PT are used in medical applications, but are not implemented in NDE. Lead Magnesium Niobate-Lead Titanate (PMN-PT) is well known for its high sensitivity and broad frequency spectrum. While conventional PZT materials have an electromechanical coupling factor K33 (a measure of the conversion between electrical and acoustic energy) of about 0.72, PMN-PT materials reach peak values of more than 0.93. For applications with low signal amplitudes, high electronic noise and small transducer elements, the performance of ultrasonic probes can be significantly enhanced by using Lead Magnesium Niobate-Lead Titanate (PMN-PT) instead of PZT. This single-crystal material offers significantly better piezo parameters and leads to a higher sensitivity and larger bandwidth. There is a better depth resolution possible with this transducers as practical tests have shown. Similar to PZT it can also be fabricated in 1-3 piezo- composite technology. In a cooperation between Fraunhofer IKTS, iBULe Photonics, and IFU Diagnostic Systems, PMN-PT ultrasonic transducers are developed and optimized. The performance of phased array probes and single element transducers was measured by a so called PCUS® pro electronic front end from Fraunhofer and compared with equivalent PZT-based probes. As a result various single element and phased array transducers with im-proved performances are available for NDT of typical aerospace materials and applications. These test setups were used to weigh up the advantages and disadvantages, such as achievable precision or costs, for the implementation of a PMN-PT-based UT matrix probe. Based on this, a wiring variant adapted to the PMN-PT was developed and optimised for the matrix setups by pre- assembling the matching layers. The most favourable setup turned out to be bonding the PMN- PT composites to the prefabricated matching layers together with a rigid-flexible PCB frame. This enabled direct wire bonding of 64 matrix elements to the matching PCB pads on the rigid frame.

Flexible, photoluminescent 0D Cs4PbX6 (X = Br, Br/I)–PMMA composite films for white LED via water-induced recrystallization

Abstract3D CsPbX3 inorganic perovskite materials have attracted much attention in optoelectronic devices because of their strong absorbance, high photoluminescent quantum yield, tunable band gap, and narrow emission bandwidth. However, their practical usefulness is limited due to their poor stability in ambient conditions. Here, we created photoluminescent 0D Cs4PbX6 (X = Br, Br/I) suspensions in toluene by adding a small amount of water. The photoluminescent 0D Cs4PbX6 perovskite was mixed with polymethylmethacrylate (PMMA) forming 0D Cs4PbX6/PMMA composite films with higher PL, stability, transparency, and transmittance than that of the 3D CsPbX3/PMMA composite films prepared separately. Moreover, the PL intensity maintains 90% of the initial value after 30 days in water, showing excellent water stability. The flexible white-light LED device prepared by the composite films illustrated good luminescence performance with color rendering index 74.77, chromaticity coordinates (0.32, 0.33), and color temperature 6997 K. Graphical abstract

CsPbBr3/Porous‐SiO2 Composite Film for Efficient Perovskite Light‐Emitting Diodes

AbstractThis study aims to enhance the performance of inorganic perovskite light‐emitting diodes (PeLEDs) by incorporating porous silica (p‐SiO2) to fabricate perovskite‐composite films for electroluminescence (EL) devices. This is because, in addition to the inorganic perovskite material, composites with inherently stable materials are needed for perovskite to ensure additional external stability. The introduced p‐SiO2 particles impede the crystal growth of perovskite during the anti‐solvent assisted crystallization process, resulting in the formation of smaller CsPbBr3 crystals in the CsPbBr3/p‐SiO2 composite film. Accordingly, compared to previous CsPbBr3 films, this composite film exhibits two folds with higher photoluminescence quantum yield (PLQY) due to improved crystalline formation. Surprisingly, the CsPbBr3/p‐SiO2 composite film additionally has good water‐resistant properties because the residual cetyltrimethylammonium bromide (CTAB) molecules are extracted from the p‐SiO2 particles and are oriented at the top surface of the CsPbBr3/p‐SiO2 composite film. The EL device fabricated with this composite film exhibits outstanding luminescence efficiency, with a current efficiency (CE) of 70.06 cd A−1 and an external quantum efficiency (EQE) of 16.97%, surpassing control samples by two folds of magnitude. Furthermore, the operational stability improves approximately sevenfold compared to the control, presenting a promising strategy for advancing the field of inorganic perovskite ELs.

Strain-induced changes in the electronic, optical and mechanical properties of the inorganic cubic halide perovskite Sr3PBr3 with FP-DFT

In recent years, inorganic perovskite materials have garnered significant attention in solar technology due to their outstanding structural, optical, mechanical, and electronic properties. A comprehensive investigation, employing first-principles density-functional theory, was conducted to assess the impact of compressive and tensile strain on the optical and electrical properties of cubic perovskite Sr3PBr3. The unstrained Sr3PBr3 exhibits a direct bandgap of 1.528 eV/2.32 eV with PBE/HSE functions at the Γ point. Under compressive strain, the bandgap decreases (1.23 eV at −4% strain), leading to a redshift in the absorption coefficient spikes, while tensile strain results in a slight bandgap increase (1.723 eV at +4 % strain) and a blueshift in absorption coefficient spikes. Total density of states was computed as 18.75 and 1.60 electrons/eV at VB and CB without strain. The value of static dielectric constant was measured as 5.24. The initial critical point of dielectric constant, large absorption peak, and maximum loss function were calculated at 1.47, 7.28, and 9.15 eV without strain. The material demonstrates excellent light absorption in the range of visible light, aligning with its electronic properties. The Sr3PBr3 perovskite is therefore thought to be perfect for usage in solar cells for the generation of power and light control.

A CsPbI3/PCBM Phototransistor with Low Dark Current by Suppressing Ion Migration

Perovskite-based metal oxide phototransistors have emerged as promising photodetection devices owing to the superior optoelectronic properties of perovskite materials and the high carrier mobility of metal oxides. However, high dark current has been one major problem for this type of device. Here, we studied the dark current behaviors of phototransistors fabricated based on the Indium Gallium Zinc Oxide (IGZO) channel and different perovskite materials. We found that depositing organic–inorganic hybrid perovskites materials (MAPbI3/FAPbI3/FA0.2MA0.8PbI3) on top of IGZO transistor can increase dark current from ~10−6 mA to 1~10 mA. By contrast, we observed depositing an inorganic perovskite material, CsPbI3, incorporated with PCBM additive can suppress the dark current down to ~10−6 mA. Our study of ion migration reveals that ion migration is pronounced in organic–inorganic perovskite films but is suppressed in CsPbI3, particularly in CsPbI3 mixed with PCBM additive. This study shows that ion migration suppression by the exclusion of organic halide and the incorporation of PCBM additive can benefit low dark current in perovskite phototransistors.

Tuning the physical properties of inorganic novel perovskite materials Ca3PX3 (X=I, Br and Cl): Density function theory

In photovoltaic technology, inorganic perovskite solar cells formed from halide have developed into a noteworthy prospect, primarily attributable to their exceptional efficiency, cost-effectiveness, and straightforward manufacturing techniques. Lead-free A3BX3 inorganic perovskites have generated significant attention within the environmentally friendly solar industry thanks to their extraordinary characteristics encompassing thermoelectricity, optoelectronics, and elasticity. This research focuses on the attributes of the structural, electrical, and optical inorganic halide perovskites Ca3PX3 (X = I, Br, and Cl) using the first-principles density-functional theory (FP-DFT). According to the electronic band structures, Ca3PI3, Ca3PBr3, and Ca3PCl3 show semiconductor characteristics with a straight bandgap of 1.4909 eV, 1.9502 eV, and 2.2058 eV, respectively, at the Γ(gamma)-point. Whenever one takes consideration into account the spin-orbital coupling (SOC) effect, the bandgap of the Ca3PI3, Ca3PBr3, and Ca3PCl3 perovskites is minimized to 1.2382 eV, 1.6456 eV, and 1.9056 eV. All these structures' bandgaps are compressed under compressive strain while they expand with tensile strain. The optical properties indicate that these materials have outstanding visible light consumption capabilities due to their distinct band features, comprising functions of dielectric, consumption coefficient, and function of electron collapse. Observations indicate that the dielectric constant peaks of Ca3PX3 (where X represents I, Br, or Cl) exhibit a redshift, moving towards lower photon energy levels as compressive strain increases. Conversely, they show a blueshift behavior, shifting to a greater amount of photon energy levels by applying tensile strain. Therefore, these characteristics render Ca3PX3 perovskites highly suitable for optimizing light guidance for solar power and energy retention tools.

Selective optosensing rutin and quercetin by novel hybrid organic–inorganic lead-free copper halide perovskite

An optical sensor based on fluorescence quenching has been developed for detecting Quercetin and Rutin. The signal source for this sensor is a hybrid organic–inorganic lead-free copper halide perovskite material, OA3Cu2I4Cl (OACuH), synthesized from octadecylamine C18H39N (OA), CuI, and CuCl. When excited at a wavelength of 355 nm, the resulting material exhibits stability and emits bright light. Characterization of the synthesized material was conducted using various methods including as X-ray powder diffraction, Fourier transform infrared (FT-IR) spectra, X-ray photoelectron spectroscopy (XPS), and fluorescent analysis. Addition of Quercetin and Rutin to OACuH resulted in a reduction in its fluorescence. The proposed sensor demonstrates excellent selectivity and a low limit of detection (70 nM for quercetin and 50 nM for rutin) within the range of 0.1–200 µM. The reliability of the proposed assay was validated by quantifying Rutin and Quercetin in fruit samples.

Impact of the structural interplay between methyl amine cation and inorganic lead-halide cage of organic perovskites on the optoelectronic properties

Energy harvesting systems using organic–inorganic metal perovskite materials are the subject of active research and development. The synthesis protocols as well as the composition, structure, and stability of these materials are still up for dispute. There are relatively few studies available correlating the relation between the optical band gap and the composition of bulk perovskite materials. Given this, the primary goal of this work is to investigate the influence of structural interplay between methyl amine cation and an inorganic lead-halide cage of organic perovskites by varying the halide functionality of lead halide. Three different products have been synthesised, namely: Methyl ammonium lead iodide-chloride (CH3NH3PbICl2), methyl ammonium lead iodide-bromide (CH3NH3PbIBr2) and methyl ammonium lead iodide (CH3NH3PbI3). This work is a first-hand report that sheds light on the importance of the interplay between the electrostatic forces generated by the methyl ammonium group and the metal halide framework of organic perovskite on its optoelectronic properties.

MAPbI3 perovskite photodetectors for high-performance optical wireless communication

High-sensitivity and fast-response photodetectors (PDs) are vital part of optical wireless communication (OWC) system. In this work, we develop an organic–inorganic hybrid perovskite material (MAPbI3) based p–i–n structured PD. By optimizing the precursor solution concertation, the PD showed a high responsivity of 0.98 A W−1, a fast response time t rise/t fall of 12/12.5 μs, a specific detectivity of 2.62 × 1013 Jones, and the f−3dB of 24 kHz under the 532 nm laser and −0.2 V bias voltage. Furthermore, we designed an OWC system based on the prepared PD. With the baud rate of 19200 bps, the system exhibits a bit error rate less than 10−6, and it can realize 9.63 m long-distance communication and quick transmission applications such as strings, texts, photos, and audios. Our work demonstrates the great application potential of perovskite PDs in the field of optical communication.

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

Modeling and enhancement of double perovskite solar cell using WO3 as electron transporting material and SrCu2O2 as hole transporting material

There is a growing necessity to develop renewable energy with cost-effective materials. In this work, a double perovskite-based solar cell design has been proposed. The proposed design is numerically simulated, and investigation of solar cell parameters has been carried out using SCAPS-1D simulation software. (FA)2BiCuI6 is an organic–inorganic double perovskite material employed as an absorber layer. SrCu2O2 is used as hole transporting material and WO3 is used as electron transporting material in proposed device model FTO/WO3/(FA)2BiCuI6/SrCu2O2/W. SrCu2O2 absorbs lower light due to its wide bandgap and provides better hole transport capability which reduces the recombination. WO3 has tunable bandgap and absorb light in visible spectrum and offer good conductivity and thus this combination improve the power conversion efficiency. The analysis and optimization of the various parameters of absorber layer such as thickness, shallow acceptor density, and operating temperature are done. At 500 nm absorber thickness for shallow acceptor density of 1.0 × 1018 cm−3 and 300 K operating temperature, the optimized results have been observed. The photo-voltaic parameters: open circuit voltage 1.04 V, short circuit current density 25.97 mA/cm2, fill factor 88.23 % and power conversion efficiency of the device 23.64 % are observed. The proposed configuration is a promising candidate for efficient, low-cost double perovskites-based solar cells.

Predicting the band gap of lead-free inorganic double perovskites using modified parallel residual network

The rapid and precise screening of appropriate inorganic perovskite materials poses a formidable challenge in the field of materials science. Traditional methods for material screening are not only time-consuming but also demand a substantial workforce. In this study, we introduce a modified parallel residual network (PRN) for the purpose of predicting the band gap of lead-free inorganic double perovskite materials, utilizing the atomic composition as the input data. The predictive performance of PRN is assessed using root mean square error (RMSE) and Pearson correlation coefficient ( r) as evaluation metrics. The PRN model yields a band gap prediction with an RMSE of 0.402 eV and an r value of 0.962, respectively. Notably, PRN outperforms various alternative models, including random forest regression (RFR), kernel ridge regression (KRR), support vector regression (SVR), extreme gradient boosting regression (XGBR), one-layer residual variant network (OLRN), and three-layer parallel residual variant network (TLPRN), clearly demonstrating its superior predictive accuracy.

Investigation of efficiency and temperature dependence in RbGeBr3-based perovskite solar cell structures

This study is centered on the exploration of the inorganic perovskite material RbGeBr3 as an absorbing layer in various configurations of perovskite solar cells (PSCs). The Poisson, continuity, and transport equations are solved using the finite element method for calculation. Systematic variations in the thicknesses of the RbGeBr3 absorber layer and the electron transfer layer are performed, with gold (Au) and silver (Ag) utilized as metal contacts for the electrodes. The study also delves into the impact of temperature variations on the efficacy of these structures. Among the tested configurations, the FTO/TiO2/RbGeBr3/P3HT/Au configuration emerges as the most efficient, achieving a power conversion efficiency of 11.89 %, with a short-circuit current of 14.47 mA/cm2 and an open-circuit voltage of 0.96 V. Additionally, two alternative structures, FTO/ITO/RbGeBr3/PEDOT:PSS/Au and FTO/ITO/RbGeBr3/PEDOT:PSS/Ag, are investigated, yielding comparable power conversion efficiencies of 11.374 %. The findings of this study can serve as valuable insights for the design of more advanced and efficient perovskite solar cells based on mineral perovskite layers.

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

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

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.

Layer-dependent spin texture and origins of Rashba splitting quenching in the 2D CsPbI3 perovskite.

The spin-orbit coupling in inorganic perovskite materials containing heavy elements causes interesting electronic characteristics such as Rashba and Dresselhaus effects. Several studies have reported significant band splitting in the presence of asymmetry, while the impacts of the external field strength, surface termination on the electronic structure still need to be resolved. In the current study, a systematic relation between the external parameters and the band splitting in CsPbI3 slabs is clarified through first-principles calculations. Here, we examine the band splitting and spin patterns of CsPbI3 slabs exposed to an external electric field ranging from zero to hundreds of kV cm-1. Our results indicate apparent non-linear behavior of the Rashba coefficient along with a turning point for the band splitting for a definite external field. Here, the origin of this quench in the band splitting is explained in terms of spatial localization of the wave functions and clear change in their center of charge going from low to high electric fields. The findings not only explain the origin of quenching band splitting but also reveal the external field's significance in the spin texture and recombination rate of 2D perovskites. The current research outcome paves the way for atomic scale engineering of perovskite materials for a wide range of applications.

Physically realistic, parametric model for excitonic critical point parabolic band oscillators

Critical point parabolic band (CPPB) oscillators are often useful to model the optical response of semiconductor materials, such as hybrid organic–inorganic lead halide-based perovskites, to incident photons in the form of the complex dielectric function (ε=ε1+iε2) spectra. Some models of ε using CPPB oscillators are not guaranteed Kramers–Kronig (KK) consistent (and therefore not physically realistic), may have excess or arbitrary parameter values, or may require prohibitively long computational time when used to fit ellipsometric spectra. For excitonic CPPBs, commonly used to describe the optical response of hybrid organic–inorganic lead halide-based perovskite materials, a physically realistic, parametric model of ε is developed from the KK relationship between ε1 and ε2 for a number of CPPB oscillators with an Urbach tail below the lowest direct transition. This parametric model is shown to produce the same line shape reported from previous works accurately and more quickly than other available KK-consistent CPPB models.

Exploring Data Augmentation and Dimension Reduction Opportunities for Predicting the Bandgap of Inorganic Perovskite through Anion Site Optimization

Significant focus has been directed towards inorganic perovskite solar cells because of their notable capabilities in converting sunlight to electricity effectively, their efficient light absorption, and their suitability for conventional semiconductor manufacturing methods. The identification of the composition of perovskite materials is an ongoing challenge to achieve high performing solar cells. Conventional methods of trial and error frequently prove insufficient, especially when confronted with a multitude of potential candidates. In response to this challenge, the suggestion is to employ a machine-learning strategy for more precise and efficient prediction of the characteristics of new inorganic perovskite materials. This work utilized a dataset sourced from the Materials Project database, consisting of 1528 ABX3 materials with varying halide elements (X = F, Cl, Br, Se) and information regarding their bandgap characteristics, including whether they are direct or indirect. By leveraging data augmentation and machine learning (ML) techniques along with a collection of established bandgap values and structural attributes, our proposed model can accurately and rapidly predict the bandgap of novel materials, while also identifying the key elements that contribute to this property. This information can be used to guide the discovery of new organic perovskite materials with desirable properties. Six different machine learning algorithms, including Logistic Regression (LR), Multi-layer Perceptron (MLP), Decision Tree (DT), Support Vector Machine (SVM), Extreme Gradient Boosting (XGBoost), and Random Forest (RF), were used to predict the direct bandgap of potential perovskite materials for this study. RF yielded the best experimental outcomes according to the following metrics: F1-score, Recall, and Precision, attaining scores of 86%, 85%, and 86%, respectively. This result demonstrates that ML has great potential in accelerating organic perovskites material discovery.

Short review on self-healing perovskite Materials: Advances and prospects

One primary area of research the world over is regarding the consumption of energy without causing harm to our environment. In this paper, a review of current advancements in the sphere of combining photovoltaic devices with self-healing technology is presented. The durability of solar cells is a crucial aspect for long-term usage. The two different categories of systems investigated herewith are polycrystalline self-healing perovskites and lead-free self-healing perovskites. There have been in-depth discussions on current trends in the selection of organic–inorganic lead halide perovskite materials for perovskite solar cells, as well as significant elements that affect the operations of solar cells. This article provides a thorough overview of current developments in the field of self-healing perovskites and presents a roadmap for creating lead-free self-healing perovskites that are more durable, stable, and effective.

Exploring the impact of strain on the electronic and optical properties of inorganic novel cubic perovskite Sr3PI3

Inorganic perovskite materials have drawn great attention in the realm of solar technology because of their remarkable structural, electronic, and optical properties. Herein, we investigated strain-modulated electronic and optical properties of Sr3PI3, utilizing first-principles density-functional theory (FP-DFT) in detail. The SOC effect has been included in the computation to provide an accurate estimation of the band structure. At its Г(gamma)-point, the planar Sr3PI3 molecule exhibits a direct bandgap of 1.258 eV (PBE). The application of the spin-orbit coupling (SOC) relativistic effect causes the bandgap of Sr3PI3 to decrease to 1.242 eV. Under compressive strain, the bandgap of the structure tends to decrease, whereas, under tensile strain, it tends to increase. Due to its band properties, this material exhibits strong absorption capabilities in the visible area, as evidenced by optical parameters including dielectric function, absorption coefficient, and electron loss function. The increase in compressive or tensile strain also causes a red-shift or blue-shift behavior in the photon energy spectrum of the dielectric function and absorption coefficient. Finally, the photovoltaic (PV) performance of novel Sr3PI3 absorber-based cell structures with SnS2 as an Electron Transport Layer (ETL) was systematically investigated at varying layer thicknesses using the SCAPS-1D simulator. The maximum power conversion efficiency (PCE) of 28.15% with JSC of 34.65 mA cm−2, FF of 87.30%, and VOC of 0.92 V was found for the proposed structure. Therefore, the strain-dependent electronic and optical properties of Sr3PI3 studied here would facilitate its future use in the design of photovoltaic cells and optoelectronics.