Perovskite Composition Research Articles

In situ Blending For Co-Deposition of Electron Transport and Perovskite Layers Enables Over 24% Efficiency Stable Conventional Solar Cells.

Simplifying the manufacturing processes of multilayered high-performance perovskite solar cells (PSCs) is yet of vital importance for their cost-effective production. Herein, an in situ blending strategy is presented for co-deposition of electron transport layer (ETL) and perovskite absorber by incorporating (3-(7-butyl-1,3,6,8-tetraoxo-3,6,7,8-tetrahydrobenzo- [lmn][3,8]phenanthrolin-2(1H)-yl)propyl)phosphonic acid (NDP) into the perovskite precursor solutions. The phosphonic acid-like anchoring group coupled with its large molecular size drives the migration of NDP toward indium tin oxide (ITO) surface to form a distinct ETL during perovskite film forming. This strategy circumvents the critical wetting issue and simultaneously improves the interfacial charge collection efficiencies. Consequently, n-i-p PSCs based on in situ blended NDP achieve a champion power conversion efficiency (PCE) of 24.01%, which is one of the highest values for PSCs using organic ETLs. This performance is notably higher than that of ETL-free (21.19%) and independently spin-coated (21.42%) counterparts. More encouragingly, the in situ blending strategy dramatically enhances the device stability under harsh conditions by retaining over 90% of initial efficiencies after 250h in 100°C or 65% humidity storage. Moreover, this strategy is universally adaptable to various perovskite compositions, device architectures, and electron transport materials (ETMs), showing great potential for applications in diverse optoelectronic devices.

Growth and photoelectrical properties of CsPbBr3-xIx (0 ≤ x < 1) single crystals

The all-inorganic halide perovskite CsPbBr3 possesses excellent optoelectronic characteristics and has a high opportunity for application in a variety of photoelectric devices. CsPbBr3 is known for its relatively low ionic migration and higher resistivity compared to other perovskite compositions. In addition, the performance in X-ray detectors can be further improved by the addition of I- dopants. The addition of I- dopants has been shown to be an effective way to improve these properties. The vertical Bridgman method was used to grown I--doped CsPbBr3 crystals. The crystal structure, optical characteristics, electrical characteristics, and X-ray detection capabilities of CsPbBr3-xIx (0 ≤ x < 1) single crystals were all systematically investigated. The results indicate that I--doping can adjust the band gap, increase the resistivity and carrier mobility, and reduce the trap density and dark current, providing the possible application of halide perovskite in various optoelectronic devices.

Bromine Incorporation Affects Phase Transformations and Thermal Stability of Lead Halide Perovskites.

Mixed-cation and mixed-halide lead halide perovskites show great potential for their application in photovoltaics. Many of the high-performance compositions are made of cesium, formamidinium, lead, iodine, and bromine. However, incorporating bromine in iodine-rich compositions and its effects on the thermal stability of the perovskite structure has not been thoroughly studied. In this work, we study how replacing iodine with bromine in the state-of-the-art Cs0.17FA0.83PbI3 perovskite composition leads to different dynamics in the phase transformations as a function of temperature. Through a combination of structural characterization, cathodoluminescence mapping, X-ray photoelectron spectroscopy, and first-principles calculations, we reveal that the incorporation of bromine reduces the thermodynamic phase stability of the films and shifts the products of phase transformations. Our results suggest that bromine-driven vacancy formation during high temperature exposure leads to irreversible transformations into PbI2, whereas materials with only iodine go through transformations into hexagonal polytypes, such as the 4H-FAPbI3 phase. This work sheds light on the structural impacts of adding bromine on thermodynamic phase stability and provides new insights into the importance of understanding the complexity of phase transformations and secondary phases in mixed-cation and mixed-halide systems.

Rubidium ion incorporation: Suppression of halide ion diffusion in perovskite films

In recent years, organic-inorganic metal halide perovskite solar cells have made significant progress in energy conversion efficiency. However, their long-term stability and performance are often affected by the diffusion of halide ions within the perovskite structure. Inhibiting the migration of halide ions is very important to improve the operational stability and efficiency of solar cells. This study proposes a new method to characterize the diffusion of halide ions in perovskite films and demonstrates the effectiveness of incorporation of Rb+ into CsMAFA perovskite compositions. The addition of Rb+ reduces the concentration of mobile ions and the conductivity of ions in the perovskite film, thus eliminating the hysteresis phenomenon of perovskite solar cells. It is found that the efficiency and stability of the device are improved after optimization.

Thermal Stability of Encapsulated Carbon-Based Multiporous-Layered-Electrode Perovskite Solar Cells Extended to Over 5000 h at 85 °C.

The key to the practical application of organometal-halide crystals perovskite solar cells (PSCs) is to achieve thermal stability through robust encapsulation. This paper presents a method to significantly extend the thermal stability lifetime of perovskite solar cells to over 5000 h at 85 °C by demonstrating an optimal combination of encapsulation methods and perovskite composition for carbon-based multiporous-layered-electrode (MPLE)-PSCs. We fabricated four types of MPLE-PSCs using two encapsulation structures (over- and side-sealing with thermoplastic resin films) and two perovskite compositions ((5-AVA)x(methylammonium (MA))1-xPbI3 and (formamidinium (FA))0.9Cs0.1PbI3), and analyzed the 85 °C thermal stability followed by the ISOS-D-2 protocol. Without encapsulation, FA0.9Cs0.1PbI3 exhibited higher thermal stability than (5-AVA)x(MA)1-xPbI3. However, encapsulation reversed the phenomenon (that of (5-AVA)x(MA)1-xPbI3 became stronger). The combination of the (5-AVA)x(MA)1-xPbI3 perovskite absorber and over-sealing encapsulation effectively suppressed the thermal degradation, resulting in a PCE value of 91.2% of the initial value after 5072 h. On the other hand, another combination (side-sealing on (5-AVA)x(MA)1-xPbI3 and over- and side-sealing on FA0.9Cs0.1PbI3) resulted in decreased stability. The FACs-based perovskite was decomposed from these degradation mechanisms by the condensation reaction between FA and carbon. For side-sealing, the space between the cell and the encapsulant was estimated to contain approximately 1,260,000 times more H2O than in over-sealing, which catalyzed the degradation of the perovskite crystals. Our results demonstrate that MA-based PSCs, which are generally considered to be thermally sensitive, can significantly extend their thermal stability after proper encapsulation. Therefore, we emphasize that finding the appropriate combination of encapsulation technique and perovskite composition is quite important to achieve further device stability.

Biocompatible Perovskite Nanocrystals with Enhanced Stability for White Light-Emitting Diodes.

Recently emerged lead halide perovskite CsPbX3 (X = Cl, Br, and I) nanocrystals (PNCs) have attracted tremendous attention due to their excellent optical properties. However, the poor water stability, unsatisfactory luminescence efficiency, disappointing lead leakage, and toxicity have restricted their practical applications in photoelectronics and biomedical fields. Herein, a controllable encapsulated strategy is investigated to realize CsPbX3 PNCs/PVP @PMMA composites with superior luminescence properties and excellent biocompatibility. Additionally, the synthesized CsPbBr3 and CsPbBr0.6I2.4 PNCs/PVP@PMMA structures exhibit green and red emissions with a maximal photoluminescence quantum yield (PLQY) of about 70.24% and 98.26%, respectively. These CsPbX3 PNCs/PVP@PMMA structures show high emission efficiency, excellent stability after water storage for 18 months, and low cytotoxicity at the PNC concentration at 500 μg mL-1. Moreover, white light-emitting diode (WLED) devices based on mixtures of CsPbBr3 and CsPbBr0.6I2.4 PNCs/PVP@PMMA perovskite structures are investigated, which exhibit excellent warm-white light emissions at room temperature. A flexible manipulation method is used to fabricate the white light emitters based on these perovskite composites, providing a fantastic platform for fabricating solid-state white light sources and full-color displays.

Bridging-Solvent Strategy for Quasi-Single-Crystal Perovskite Films and Stable Solar Cells.

Controllable fabrication of formamidinium (FA)-based perovskite solar cells (PSCs) with both high efficiency and long-term stability is the key to their further commercialization. However, the diversity of PbI2 complexes and perovskite compositions usually leads to light sensitive PbI2 residues and phase impurities in the film, which can accelerate the device degradation. Here, the crystallization kinetics of FA-based perovskite films are studied and a bridging-solvent strategy is proposed to modulate the reaction kinetics between PbI2 and ammonium salts by prohibiting the formation of undesired intermediates. N-methylpyrrolidone (NMP) solvent is introduced into the PbI2 precursor solution to obtain stable and homogeneous PbI2-NMP complex films. The strong interaction between NMP and formamidinium iodide (FAI) molecules promotes the conversion from PbI2-NMP into (001)-oriented quasi-single-crystal perovskite films with negligible impurities, long carrier lifetime of 1.5µs and a large grain size of 3µm. The optimized PSCs exhibit a high power conversion efficiency of 24.1%, as well as superior shelf stability which maintains 95% initial efficiency after storage in air for 1200h (T95=1200h), and operating stability with T96=300h under continuous working at the maximum power point. This work offers a simple and reproducible method for fabricating phase-pure and uniaxially oriented perovskite films.

Age and composition of perovskite in ultramafic lamprophyres from the Zima alkaline-ultramafic carbonatite complex, the southern margin of the Siberian craton: Petrogenetic implications

This paper presents data on the age and trace element composition of perovskites from dykes of ultramafic lamprophyres (aillikites) of the Zima alkaline-ultramafic carbonatite complex (Bolshaya Tagna and Bushkanay) located within the Urik-Iya graben, Eastern Sayan region, southern margin of the Siberian craton. The studied samples exhibit similar textural and structural features but differ slightly in the mineral composition of the groundmass. They have a porphyritic structure, a massive texture, and consist of olivine macrocrystals embedded in a fully crystallized groundmass composed of perovskite, apatite, spinel, phlogopite, garnet, carbonates, clinopyroxene and other minerals. The macrocrystals quantity varies between 40 and 50 vol%. With the exception of a single sample from the Bushkanay dyke, olivine is entirely replaced by serpentine and/or talc.Perovskites from aillikites of the Bolshaya Tagna intrusion exhibit crystals with normal zoning showing a decrease in Na, REE, and Nb contents with center-to-rim increasing Ca content. In contrast, minerals from the aillikites of the Bushkanay dyke demonstrate reverse zoning, with an increase in Na, REE, and Sr and decrease in Ca contents from the center to the rim. We suggest that during crystallization of perovskites, the magma parental to the aillikites of the Bolshaya Tagna intrusion and the Bushkanay dyke had nearly similar trace element composition, but after crystallization of the cores of perovskite crystals each melt portion evolved independently. The samples from the Bushkanay dyke show an increase in fO2 and the residual magma enrichment in REE, Na, and Sr as evidenced by their elevated contents at the rims of perovskite grains. In the Bolshaya Tagna aillikites after crystallization of perovskite cores, the melt was depleted in REE, Na, and Nb.Based on U-Pb dating of perovskites, the age of aillikites from the Bolshaya Tagna intrusion is 583–654 Ma. Perovskite from aillikites of the Bushkanay dyke is relatively young, with an age of 575 ± 39 Ma. The obtained ages are consistent with the age of formation of Neoproterozoic alkaline-ultramafic carbonatite complexes of the Siberian craton and other occurrences of aillikites in a response to extension of the Rodinia lithosphere.

Advances in chalcogenide perovskites: Fundamentals and applications

Chalcogenide perovskites are a family of compounds related to perovskite structures or compositions, which have witnessed rapid advances in recent years. They possess favorable properties such as high stability, low toxicity, direct band gaps, good carrier transport abilities, strong light absorption, and potential luminescent properties, making them stand out in emerging applications, such as photovoltaics, photodetectors, light-emitting devices, and photocatalysts, among others. In this review, we aim to provide a comprehensive overview of the properties, synthesis, and applications of chalcogenide perovskites. First, we first survey the reported material structures/compositions and current understanding of their structural/optical/electrical properties, mechanics, magnetics, and stabilities. Furthermore, we discuss the synthesis strategies of these materials covering various material types such as powders, pellets, thin films, nanocrystals, and single crystals, with a focus on their potential applications, including photovoltaics, photodetectors, and other devices. Finally, we outline a brief conclusion and some prospects for the further research of chalcogenide perovskites, thus promoting more studies and developments in this field. This review can provide new insights into the fundamental properties and potential applications of chalcogenide perovskites, and thereby facilitating their further studies and developments.

Interfacial host-guest complexation for inverted perovskite solar cells.

Perovskite solar cells have demonstrated exceptional development over the past decade, but their stability remains a challenge toward the application of this technology. Several strategies have been used to address this, and the use of host-guest complexation has recently attracted more interest. However, this approach has primarily been exploited in conventional perovskite solar cells based on n-i-p architectures, while its use in inverted p-i-n devices remains unexplored. Herein, we employ representative crown ether, dibenzo-24-crown-8, for interfacial host-guest complexation in inverted perovskite solar cells based on methylammonium and methylammonium-free formamidinium-cesium halide perovskite compositions. Upon post-treatment of the perovskite films, we observed nanostructures on the surface that were associated with the reduced amount of trap states at the interface with the electron transport layer. As a result, we demonstrate improved efficiencies and operational stabilities following ISOS-D-2I and ISOS-L-2I protocols, demonstrating the viability of this approach to advance device stability.

Thermal Stability Analysis of Formamidinium–Cesium‐Based Lead Halide Perovskite Solar Cells Fabricated under Air Ambient Conditions

The instability of perovskite solar cells (PSCs) remains a major bottleneck for their commercialization, with thermal instability posing a major concern, given the inevitable presence of heat in photovoltaic devices. Mixed‐cation/halide perovskites demonstrate enhanced stability and efficiency compared to single‐cation/halide perovskites. Identifying the optimal perovskite composition capable of withstanding high temperatures for longer durations is crucial for the development of thermally stable PSCs. This study provides valuable insights into the optimization of mixed‐cation/halide perovskites to enhance the thermal and structural stability of perovskite films. By systematically varying the Cs content in FA1−yCsyPb(I0.85Br0.15)3 (0 &lt; y &lt; 25)‐based perovskite, it is observed that controlling the Cs content allows precise modulation of crystal orientation in perovskite film with 10% Cs obtained as the optimal value. The perovskite film containing 10% Cs not only exhibits reduced microstrain but also demonstrates enhanced thermal stability during testing at 85 °C under controlled humidity. Furthermore, planar PSCs are fabricated using FA0.90Cs0.10Pb(I0.85Br0.15)3 as the absorber layer and TOP‐3 as the hole‐transporting material, achieving a promising power conversion efficiency (PCE) of 17.70%. Impressively, the unencapsulated devices retain 95% of their initial PCE after 1000 h of dark storage under ambient conditions.

Ultrasonic-assisted hydrothermal synthesis of MNCNT-decorated SmCoO3 perovskite composite: a facile approach for high-performance energy storage applications

Ultrasonic-assisted hydrothermal synthesis of MNCNT-decorated SmCoO3 perovskite composite: a facile approach for high-performance energy storage applications

Improving perovskite solar cell efficiency and prolonging durability via interface modification with guanidinium iodide by post treatment method

The performance of perovskite solar cells (PSCs) can be significantly compromised by the presence of halide vacancies on the perovskite surface, leading to defects and a decline in stability and efficiency. Effectively addressing this challenge, the application of Guanidinium iodide (GAI) as a post dopant treatment (POST) has demonstrated success. GAI (POST) not only reduces surface defects but also minimizes halide deficiencies and mitigates losses due to interfacial charge recombination. When incorporating a GAI additive at a solution concentration of 1.5 mg/ml in the modification layer with the perovskite composition Cs0.1FA0.8MA0.1PbI3, the PSC showed a notable power conversion efficiency (PCE) of 20.7%, surpassing the 16.3% efficiency of the control device. Moreover, the adapted device demonstrated an impressive fill factor (FF) of 80.1%. Notably, the enhanced film of the modified device maintained over 80% of its initial efficiency for more than 312 h, highlighting the prospect of creating affordable, effective, and durable PSCs.

Detection of alkaline phosphatase activity with a CsPbBr3/Y6 heterojunction-based photoelectrochemical sensor.

An ultra-sensitive photoelectrochemical (PEC) sensor based on perovskite composite was developed for the determination of alkaline phosphatase (ALP) in human serum. In contrast toCsPbBr3 or Y6 that generated anodic current, the heterojunction of CsPbBr3/Y6 promoted photocarriers to separate and generated cathodic photocurrent. Ascorbic acid (AA) was produced by ALP hydrolyzing L-ascorbic acid 2-phosphate trisodium salt (AAP), which can combine with the holes on the photoelectrode surface, accelerating the transmission of photogenerated carriers, leading to enhanced photocurrent intensity. Thus, the enhancement of PEC current was linked to ALP activity. The PEC sensor exhibits good sensitivity for detection of ALP owing to the unique photoelectric properties of the CsPbBr3/Y6 heterojunction. The detection limit of the sensor was 0.012 U·L-1 with a linear dynamic range of 0.02-2000 U·L-1. Therefore, this PEC sensing platform shows great potential for the development of different PEC sensors.

Perovskite solar cells with ferroelectricity

AbstractHalide perovskites show excellent optoelectronic properties for solar cell application. Notably, perovskite crystalline structures have been widely reported to deliver superior ferroelectric properties. As a result, the integration of the ferroelectric process with the photon‐to‐electron energy conversion process becomes feasible to generate interesting photo‐physical properties and further boost the device performance of perovskite solar cells (PSCs), which have started to attract more and more attention in recent years. Here, we have reviewed the recent progress in PSCs with ferroelectricity (FE‐PSCs), by classifying them into three regimes according to the degree of phase segregation, for example, the layer‐structured ferroelectric/halide perovskite composite, micro phase‐separated ferroelectric/halide perovskite composite, and the intrinsic ferroelectric halide perovskite composite. The different composite structures enable a large range of interesting optoelectronic properties and the specific structure significantly enhances the device performance of PSCs. The most prominent contribution of ferroelectricity is that it can provide an extra electrical field to drive charge generation, transport, and collection. Further, key challenges and opportunities of the integration of ferroelectricity with photovoltaics are discussed. We hope our work can draw intensive attention in this field to accelerate the establishment of the basic theories in ferroelectricity and the commercialization of PSCs.

Imbalanced Surface Charge Induced Phase Segregation in Mixed Halide Perovskites

AbstractAlloying the metal halide perovskite composition has become a key strategy for engineering the optoelectronic properties for various applications. However, the difference in complexation between ions poses a threat to crystal stability. In particular, the phase segregation in wide‐bandgap perovskites (WBG) with mixed halides is the major challenge in multi‐junction photovoltaic devices. Here, a systematic study is reported on the origin of phase segregation in a prototypical mixed halide perovskite (MHP) MAPbI2Br. It is found that the crystallinity and surface morphology are not associated with the lattice stability. Using highly sensitive external quantum efficiency (s‐EQE) measurement, it is found that the defects in the MHP are mainly associated with the Pb2+ and I−/Br− ions. Consistently, density‐function‐theory (DFT) calculation confirms that the MAPbI2Br surface is dominated by the metal‐halide components, and the imbalanced surface charge is responsible for the lattice instability. The role of physical and chemical passivation approaches in MHP is further investigated. The former limits the ion migration and allows dissociated ions to recover to their corresponding defective sites, whereas the latter lowers the surface energy by neutralizing the charge density on the lattice surface. This work brings insight into the phase segregation and passivation mechanisms in MHP.

Significance of Formamidinium Incorporation in Perovskite Composition and Its Impact on Solar Cell Efficiency: A Mini‐Review

Perovskite solar cells (PSCs) have gained tremendous research interest recently owing to several advantages, including low material cost, facile solution processability, bandgap tunability, and alluring device efficiency. The organic formamidinium (FA) cation‐based perovskites are mainly considered as one of the potential candidates for charge carrier generation due to their excellent properties, such as bandgap and thermal stability than traditional perovskites. However, the inevitable unfavorable polymorphism (i.e., α to δ) at room temperature still forms the basis for numerous research works to allow the fabrication of a high‐quality absorber and enhances the PSCs performance. The studies to resolve the polymorphism and several contemporary techniques (e.g., passivation strategy) with several recent novel fabrication methods presented in this review form the essence of the improvements in PSCs. The absorber morphology also influences the charge‐transfer behavior and the device's lifetime. Therefore, understanding these properties is essential to improve the absorber quality and avoid many defects. This review focuses on the structure and properties of pure and mixed FA perovskites with various halides, mainly the FA cation's role in the absorber composition. And a comprehensive overview of recent FA cation‐based double, triple, and quadrupole PSCs results with proper scientific explanations to understand the device physics.

Experimental Study on the Magnetic and Magnetocaloric Properties of Two Perovskite Compositions, La0.7Nd0.1Sr0.2MnO3 and La0.7Nd0.1Sr0.2Mn0.96In0.04O3, and Their Effect on Chemical Stability in Memory Devices

Experimental Study on the Magnetic and Magnetocaloric Properties of Two Perovskite Compositions, La0.7Nd0.1Sr0.2MnO3 and La0.7Nd0.1Sr0.2Mn0.96In0.04O3, and Their Effect on Chemical Stability in Memory Devices

Surface Energy-Assisted Patterning of Vapor Deposited All-Inorganic Perovskite Arrays for Wearable Optoelectronics.

Solution-based methods for fabricating all-inorganic perovskite film arrays often suffer from limited control over nucleation and crystallization, resulting in poor homogeneity and coverage. To improve film quality, advanced vapor deposition techniques are employed for continuous film. Here, the vapor deposition strategy to the all-inorganic perovskite films array, enabling area-selective deposition of perovskite through substrate modulation is expanded. It can yield a high-quality perovskite film array with different pixel shapes, various perovskite compositions, and a high resolution of 423dpi. The resulting photodetector arrays exhibit remarkable optoelectronic performance with an on/off ratio of 13 887 and responsivity of 47.5AW-1. The device also displays long-term stability in a damp condition for up to 12h. Moreover, a pulse monitoring sensor based on the perovskite films array demonstrates stable monitoring for pulse signals after being worn for 12h and with a low illumination of 0.055mWcm-2, highlighting the potential application in wearable optoelectronic devices.

Embedding Perovskite in Polymer Matrix Achieved Positive Temperature Response with Inversed Temperature Crystallization

Organic perovskites are promising semiconductor materials for advanced photoelectric applications. Their fluorescence typically shows a negative temperature coefficient due to bandgap change and structural instability. In this study, a novel perovskite‐based composite with positive sensitivity to temperature was designed and obtained based on its inverse temperature crystallization, demonstrating good flexibility and solution processability. The supercritical drying method was used to address the limitations of annealing drying in preparing high‐performance perovskite. Optimizing the precursor composition proved to be an effective approach for achieving high fluorescence and structural integrity in the perovskite material. This perovskite‐based composite exhibited a positive temperature sensitivity of 28.563% °C−1 for intensity change and excellent temperature cycling reversibility in the range of 25–40 °C in an ambient environment. This made it suitable for use as a smart window with rapid response. Furthermore, the perovskite composite was found to offer temperature‐sensing photoluminescence and flexible processability due to its components of perovskite‐based compounds and polyethylene oxide. The organic precursor solvent could be a promising candidate for use as ink to print or write on various substrates for optoelectronic devices responding to temperature.