Organic-inorganic Hybrid Perovskite Research Articles

Atomic-Scale Friction and Adhesion at Ambient Pressure.

In this Perspective, we present the recent advancement and the prospects of atomic-scale friction and adhesion measurements across the pressure gap between ultrahigh vacuum and ambient pressure environments using variable-pressure atomic force microscopy (VP-AFM). We introduce the VP-AFM that enables nanotribological studies under various gas conditions with partial pressure ranging from UHV (1.0 × 10-10 mbar) to 1 bar. We highlight the frictional behaviors of ultrananocrystalline diamond surface in oxygen and water gas environments, as well as the chemical states probed with near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS). The atomic scale degradation processes of MA(CH3NH3)PbBr3, which is an organic-inorganic hybrid perovskite (OHP) investigated with VP-AFM are introduced. Finally, we discuss the potential works on catalytic model systems including bimetallic Pt3Ni(111) and TiO2(110) and the future perspective of nanotribology under ambient conditions.

Effect of organic spacer cations on the stability of organic–inorganic hybrid perovskite thin film transistors

Effect of organic spacer cations on the stability of organic–inorganic hybrid perovskite thin film transistors

Accurate Crystal Structure Prediction of New 2D Hybrid Organic-Inorganic Perovskites.

Low-dimensional hybrid organic-inorganic perovskites (HOIPs) are promising electronically active materials for light absorption and emission. The design space of HOIPs is extremely large, as a variety of organic cations can be combined with different inorganic frameworks. This not only allows for tunable electronic and mechanical properties but also necessitates the development of new tools for in silico high throughput analysis of candidate materials. In this work, we present an accurate, efficient, and widely applicable machine learning interatomic potential (MLIP) trained on 86 diverse experimentally reported HOIP materials. This MLIP was tested on 73 experimentally reported perovskite compositions and achieves a high accuracy, relative to density functional theory (DFT). We also introduce a novel random structure search algorithm designed for the crystal structure prediction of 2D HOIPs. The combination of MLIP and the structure search algorithm reliably recovers the crystal structure of 14 known 2D perovskites by specifying only the organic molecule and inorganic cation/halide. Performing this crystal structure search with ab initio methods would be computationally prohibitive but is relatively inexpensive with the MLIP. Finally, the developed procedure is used to predict the structure of a totally new HOIP with cation (cis-1,3-cyclohexanediamine). Subsequently, the new compound was synthesized and characterized, which matches the predicted structure, confirming the accuracy of our method. This capability will enable the efficient and accurate screening of thousands of combinations of organic cations and inorganic layers for further investigation.

High performance self-powered photodetection and X-ray detection realized by CH3NH3PbI3 single crystal with planar asymmetric Schottky structure

Organic-inorganic hybrid perovskite CH3NH3PbI3 (MAPbI3) single crystals (SCs) have been widely investigated in photodetection and X-ray detection. However, external electric-field-driven ion migration seriously affect the stability of MAPbI3 SCs based optoelectronic devices. Self-powered device can operate without any external power supply, which is suitable for mitigating the ion migration of MAPbI3 SCs. To realize self-powered MAPbI3 SC based photodetector and X-ray detector, an asymmetric Au/CH3NH3PbI3 SC/Au planar Schottky structure is employed in this work. At 0 V, the self-powered photodetector can achieve the responsivity of 11.1 mA/W at the wavelength of 795 nm, and the sensitivity of the self-powered X-ray detector can reach 477.1 μC Gy-1cm-2 with the detection limit of as low as 140.3 nGy s-1. Moreover, the self-powered optoelectronic device exhibits good stability in both photodetection and X-ray detection. Most importantly, high-quality near-infrared bioimaging and X-ray imaging are successfully realized by the above self-powered optoelectronic device.

Enhancing precursor stability with suitable additives to enable blade-coating of organic-inorganic hybrid perovskites at room temperature for efficient perovskite solar modules

In this study, room temperature blade coating organic-inorganic hybrid perovskite (OIHP) films with the precursors made of adding additives such as dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), and N-methyl-2-pyrrolidone (NMP) to the volatile solvent of 2-methoxylethanol (2-ME) were explored. Unlike NMP, DMSO and DMF interact with the perovskites to form Lewis adducts, suggesting important factors beyond the Gutmann donor number and dielectric constant, such as molecular structure, influence adduct formation. The OIHP solar cells made of the precursors with optimized amount of DMSO, DMF and NMP showed the efficiency of 16.5 %, 16.1 % and 8.3 %, respectively. After optimizing the blade-coating process for OIHP film formation by using the Taguchi's method, the optimized OIHP solar modules (active area = 25.2 cm2) achieve PCEs of 14.6 % and 14.1 % with the precursor added 20 mol% DMSO and 30 mol% DMF, respectively. Moreover, the precursor added with DMF demonstrates better storage stability than that of DMSO, achieving the best module PCE of 13.4 % fabricated from the 3-day stored DMF-added precursors, while the module fabricated from the DMSO-added precursor shows a PCE of 9.1 %.

A Hybrid Perovskite-Based Electromagnetic Wave Absorber with Enhanced Conduction Loss and Interfacial Polarization through Carbon Sphere Embedding.

Electronic equipment brings great convenience to daily life but also causes a lot of electromagnetic radiation pollution. Therefore, there is an urgent demand for electromagnetic wave-absorbing materials with a low thickness, wide bandwidth, and strong absorption. This work obtained a high-performance electromagnetic wave absorption system by adding conductive carbon spheres (CSs) to the CH3NH3PbI3 (MAPbI3) absorber. In this system, MAPbI3, with strong dipole and relaxation polarization, acts dominant to the wave absorber. The carbon spheres provide a free electron transport channel between MAPbI3 lattices and constructs interfacial polarization loss in MAPbI3/CS. By regulating the content of CSs, we speculate that this increased effective absorption bandwidth and reflection loss intensity are attributed to the conductive channel of the carbon sphere and the interfacial polarization. As a result, when the mass ratio of the carbon sphere is 7.7%, the reflection loss intensity of MAPbI3/CS reaches -54 dB at 12 GHz, the corresponding effective absorption bandwidth is 4 GHz (10.24-14.24 GHz), and the absorber thickness is 2.96 mm. This work proves that enhancing conduction loss and interfacial polarization loss is an effective strategy for regulating the properties of dielectric loss-type absorbing materials. It also indicates that organic-inorganic hybrid perovskites have great potential in the field of electromagnetic wave absorption.

Progress of Hole-Transport Layers in Mixed Sn-Pb Perovskite Solar Cells.

Hybrid organic-inorganic lead halide perovskite solar cells (PSCs) have rapidly emerged as a promising photovoltaic technology, with record efficiencies surpassing 26%, approaching the theoretical Shockley-Queisser limit. The advent of all-perovskite tandem solar cells (APTSCs), integrating Pb-based wide-bandgap (WBG) with mixed Sn-Pb narrow-bandgap (NBG) perovskites, presents a compelling pathway to surpass this limit. Despite recent innovations in hole transport layers (HTLs) that have significantly improved the efficiency and stability of lead-based PSCs, an effective HTL tailored for Sn-Pb NBG PSCs remains an unmet need. This review highlights the essential role of HTLs in enhancing the performance of Sn-Pb PSCs, focusing on their ability to mitigate non-radiative recombination and optimize the buried interface, thereby improving film quality. The distinct attributes of Sn-Pb perovskites, such as their lower energy levels and accelerated crystallization rates, necessitate HTLs with specialized properties. In this study, the latest advancements in HTLs are systematically examined for Sn-Pb PSCs, encompassing organic, self-assembled monolayer (SAM), inorganic materials, and HTL-free designs. The review critically assesses the inherent limitations of each HTL category, and finally proposes strategies to surmount these obstacles to reach higher device performance.

Self-Assembled Monolayer Suppresses Interfacial Reaction between NiOx and Perovskite for Efficient and Stable Inverted Inorganic Perovskite Solar Cells.

Inorganic NiOx has attracted tremendous attention in organic-inorganic hybrid perovskite solar cells (PSCs) in recent years but is relatively less used in all-inorganic PSCs. In this study, we have discovered and confirmed the detrimental interfacial reaction between NiOx and DMAI-containing CsPbI3 inorganic perovskites. Thus, a self-assembled monolayer, Br-2PACz, is employed to modify the NiOx surface to obstruct the adverse interfacial reaction and further improve the device performance. The results demonstrate that Br-2PACz modification on NiOx can also improve interface contact, perovskite film morphology, and energy level alignments. Consequently, a champion power conversion efficiency (PCE) of 19.34% with a high open-circuit voltage (VOC) of 1.15 V is obtained for inverted NiOx/Br-2PACz-based CsPbI3 PSCs compared to the reference NiOx-based PSC with a moderate PCE of 15.16% (VOC 1.05 V). Moreover, the stabilities of both CsPbI3 films and devices exhibited significant enhancement after Br-2PACz modification. The unpacked PSCs could maintain 80, 73, and 89% of the initial efficiency after aging in 30-35% RH for 960 h, heating at 60 °C for 48 h, and continuous illumination for 284 h, respectively, highly superior to the reference devices. Our work offers a facile and effective approach for developing high-performance inverted NiOx-based CsPbI3 PSCs.

Highly stable and self-powered ultraviolet photodetector based on Dion-Jacobson phase lead-free double perovskite

Metal halide perovskite materials present a wide array of opportunities for the development of high-performance optoelectronic devices, owing to their outstanding photoelectric properties. Compared with the lead-containing perovskites, stable and non-toxic organic-inorganic hybrid perovskites exhibit enhanced potential for future commercial applications. In this work, we developed a self-powered UV photodetector based on 2D Dion−Jacobson (DJ) phase lead-free double perovskite HAAg0.5Bi0.5Br4 (HA2+ = histammonium) perovskite with an on-off ratio up to 2.66 × 106, excellent specific detectivity of 6 × 1012 Jones, and response speed of 1.32 ms/118.4 μs. The light intensity related pyro-phototronic effect on 2D perovskite is thoroughly investigated. Temperature and light detection are realized through multi-energy coupling, which greatly improves the detection performance. Coupled pyro-phototronic current is calculated nearly 75 folds higher than that from the photoelectronic merely. As-prepared photodetector film shows excellent stability in normal environment, maintaining a value of 90 % to the initial performance after 500 cycles and 90 days. This work provides a new self-powered, stable and non-toxic candidate for the future UV photodetectors.

Thermal-triggered healing strategy for efficient and stable perovskite solar cells with efficiency over 25 %

The power conversion efficiency (PCE) of organic-inorganic hybrid perovskite solar cells (PSCs) is hindered by the abundant defects within the grain boundaries (GBs) of perovskite films. Herein, a directed thermal-triggered healing strategy based on phthalide-3-acetic acid (P3AC) is proposed, aiming to mitigate GBs defects and optimize energy level arrangement by utilizing the strong polarity effect of P3AC and its thermal-triggered interaction with perovskite. The introduced dual-sites molecular (P3AC) anchors at the GBs of perovskite, which can passivate the uncoordinated Pb2+ and form hydrogen bonds with FA+, yielding dense, uniform and low-defects and large-grain perovskite film. Compared to the pristine devices, the P3AC-modified devices achieved a champion PCE of 25.28 % (certified PCE of 24.46 %) and impressive operational stability. This work provides an effective and direct solution for enhancing the performance of PSCs.

Performance and stability of different all-inorganic and hybrid organic-inorganic perovskites in p-n planar device structure FTO/SnO2/Perovskite/Cu2O/Carbon using SCAPS-1D simulation

Performance and stability of different all-inorganic and hybrid organic-inorganic perovskites in p-n planar device structure FTO/SnO2/Perovskite/Cu2O/Carbon using SCAPS-1D simulation

Geometric optimisation and structural properties of organic−inorganic halide perovskites from van der Waals density functional theory calculations

Organic–inorganic hybrid perovskites have attracted extensive attention in the photovoltaic field due to their unique photoelectric properties and low production costs. Using the density functional theory-based first-principles calculations, we reported the geometric optimisation and structural properties of halide perovskites using van der Waals density functional theory calculations. The strongly constrained and appropriately normed (SCAN) meta-GGA with the revised Vydrov-van Voorhis no-local correlation functional (SCAN + rVV10) are promising van der Waals density functional for solving van der Waals (vdW) interaction problems that many non-empirical semilocal functionals fail to include. We found the optimised structure parameters of halide perovskites based on the SCAN + rVV10 functionals are much closer to the experimental results than other functional including PBE and PBE + vdW-TS functionals, which provides the fundamental aspect for the theoretical calculations of surfaces, interfaces, optical properties, and structure-properties relationship.

Investigation of the temperature-dependent photoluminescence characteristics in Mn2+-doped (PEA)2PbBr4 perovskite

The two-dimensional organic-inorganic hybrid perovskites demonstrate significant potential for use in photodetectors and white light-emitting diodes. In this study, we successfully synthesized pure and Mn2+-doped (PEA)2PbBr4 perovskite via rapid crystallization. The morphology, structure, magnetic properties, and optical characteristics of them were comprehensively characterized. The unusual behavior of free exciton emission is mainly attributed to electron-phonon coupling and negative thermal quenching effects. The self-trapped exciton emission results from self-trapped excited states and electron-phonon coupling. Moreover, energy transfer phenomena are observed between free exciton emission, self-trapped exciton emission, and Mn2+ emission. These findings offer valuable insights into the luminescence mechanism of two-dimensional layered perovskites.

Rare earth Nd3+-doped organic-inorganic hybrid perovskite quantum dots for white LED

Lead halide perovskite quantum dots (QDs) have garnered significant attention due to their tunable band gaps, unique quantum confinement effects, and high photoluminescence quantum yields (PLQYs). Among them, Organic-inorganic QDs make them promising candidates for optoelectronic devices such as quantum dot light-emitting diodes (QLEDs), solar cells, lasers, and photodetectors. However, the toxicity of lead (Pb) has raised environmental and health concerns, hindering their industrial application. To alleviate concerns about heavy metals Pb, extensive research has been conducted on B-site doping and the development of lead-free perovskites. Herein, we firstly developed B-site doping strategy on organic-inorganic hybrid perovskite QDs via rare-earth elements. Neodymium (III) (Nd3+) doped FAPbBr3 QDs were prepared through the ligand-assisted reprecipitation method at room temperature. The B-site doping strategy could alleviate the heavy metal problem of Pb and modulate the band gap of FAPbBr3 QDs facilely. The results demonstrated that increasing the concentration of Nd³⁺ can change the emission of FAPbBr₃ QDs from pure green to deep blue. Specifically, we achieved highly pure blue emission (∼438 nm) with a full width at half maximum (FWHM) of 13 nm for Nd³⁺-doped FAPbBr₃ QDs. Time-resolved photoluminescence (TRPL) spectroscopy revealed a decrease in the lifetime of FAPbBr₃ QDs from 22.86 to 15.46 ns as the doping concentration increased. Additionally, we fabricated a white LED (WLED) utilizing blue-emitting Nd³⁺-doped FAPbBr₃, green-emitting FAPbBr₃ QDs, and red QDs, achieving a white emission color coordinate of (0.33, 0.36). This study pioneers the application of B-site rare-earth doping in organic-inorganic hybrid perovskite QDs, demonstrating that B-site composition engineering is a reliable strategy to further exploit the perovskite family for wider optoelectronic applications.

Reducing Dielectric Confinement Effect Enhances Carrier Separation in Two‐Dimensional Hybrid Perovskite Photocatalysts

AbstractTwo‐dimensional organic–inorganic hybrid perovskites (OIHPs) with alternating structure of the organic and inorganic layers have a natural quantum well structure. The difference of dielectric constants between organic and inorganic layers in this structure results in the enhancement of dielectric confinement effect, which exhibits a large exciton binding energy and hinders the separation of electron‐hole pairs. Herein, a strategy to reduce the dielectric confinement effect by narrowing the dielectric difference between organic amine molecule and [PbBr6]4− octahedron is put forward. The Ethanolamine (EOA) contains hydroxyl groups, resulting in the positive and negative charge centers of O and H non‐overlapping, which generated a larger polarity and dielectric constant. The reduced dielectric constant produces a smaller exciton binding energy (71.03 meV) of (C2H7NO)2PbBr4 ((EOA)2PbBr4) than (C8H11N)2PbBr4 ((PEA)2PbBr4 (156.07 meV), and promotes the dissociation of electrons and holes. The increasing of lifetime of photogenerated carrier in (EOA)2PbBr4 are proved by femtosecond transient absorption spectra. Density functional theory (DFT) calculations have also indicated that the small energy shift of the total density of states (DOS) between the C/H/N and the Pb/Br in (EOA)2PbBr4 favors the separation of electrons and holes. In addition, this work demonstrates the application of (PEA)2PbBr4 and (EOA)2PbBr4 in the field of photocatalytic CO2 reduction.

Lead-free Cs3Bi2I9 perovskite hexagonal microplates: A promising material solution-processed for ultraviolet self-powered photodetectors

In recent times, hybrid organic-inorganic lead halide perovskites have garnered significant attention in the realm of optoelectronic devices. Metal halide perovskites are extensively researched for photodetection due to their exceptional optical and electrical properties. However, the toxicity of lead and the unstable nature of organic components are limiting its potential. Lead-free perovskites, on the other hand, have low toxicity and are being explored as a promising material for photodetector applications. However, achieving self-powered perovskite photodetectors with high photoresponse, broad spectral sensitivity, and long-term stability remains challenging Among them, Cs3Bi2I9 perovskites have emerged as standout, garnering attention for their environmentally friendly nature, impressive stability, and heightened photosensitivity. Herein, FTO/ Al-doped ZnO (AZO)/Cs3Bi2I9/P3HT/C self-powered ultra-violet (UV) photodetector. This device demonstrated outstanding self-powered photodetection capabilities with a photoresponsivity of 29 mA/W, a specific detectivity of 1.05×1011 Jones, and an impressive response rise and decay time of 90 ms /140 ms. Furthermore, the PDs device can function as a bias-based UV photodetector.

Encapsulating Halide Perovskite Quantum Dots in Metal–Organic Frameworks for Efficient Photocatalytic CO2 Reduction

Halide perovskite has shown great potential in photocatalysis owing to its diversity, suitable energy band alignment, rapid charge transfer, and excellent optical properties. However, poor stability, especially under humid conditions, hinders their practical application in photocatalysis. In this work, we report the encapsulation of inorganic–organic hybrid perovskite QDs into MIL-101(Cr) through an in situ growth strategy to prepare a series of MAPbBr3@MIL-101(Cr) (MA = CH3NH3+) composites. The perovskite precursors, i.e., MABr and PbBr2, were successively introduced into the pores of MOF, where the perovskite quantum dots were self-assembled in the confined environment. In photocatalytic CO2 reduction, 11%MAPbBr3@MIL-101(Cr) composite displayed the best performance among the composites with a total CO and CH4 yield of 875 μmol g−1 in 9 h, which was 8 times higher than that of the pure MAPbBr3. Such high gas production efficiency could be maintained for 78 h at least without structural and morphologic decomposition. The remarkable stability and catalytic activity of composites are mainly due to the synergistic effect and improved electron transfer between MAPbBr3 and MIL-101(Cr). Moreover, these composites revealed a novel mechanism, showing switched CH4 selectivity with the controlling of the perovskite location and contents. Those with perovskites encapsulated in the mesopores of MIL-101(Cr) were more preferential for CO production, while those with perovskites encapsulated in both meso- and micropores could produce CH4 dominantly.

Energy harvesting and human motion sensing of a 2D piezoelectric hybrid organic–inorganic perovskite

Two-dimensional (2D) hybrid organic–inorganic perovskites (HOIPs) have garnered plentiful attention as a result of their exceptional structural flexibility and multiple applications. In this study, we present a 2D HOIP (CHA)2PbBr4 (CHA = cyclohexylamine), for its potential applications in piezoelectricity, such as strain energy sensing and harvesting. Flexible composite films of (CHA)2PbBr4/PDMS (PDMS = polydimethylsiloxane) with a sequence of weight ratios (0, 5, 10, 15, 20 wt %) of (CHA)2PbBr4 were fabricated to analyze the energy harvesting properties. Experimental results demonstrated that a device with 15% composition exhibited the most optimized performance in energy harvesting, producing a peak magnitude of output voltage of 11.6 V, a short-circuit current of 0.38 µA, and a power density of 6.77 µW/cm2, along with notable stability exceeding 4000 cycles. Furthermore, this device exhibited high sensitivity in monitoring many varieties of human movements, such as finger bending and tapping, elbow bending, and gentle foot stamping. The findings of this study indicate that this 2D HOIP holds significant potential for use in flexible sensing and intelligent wearable devices.

Fluorinated Organic Cations Derived Chiral 2D Perovskite Enabling Enhanced Spin-Dependent Oxygen Evolution Reaction.

Chirality-induced spin selectivity observed in chiral 2D organic-inorganic hybrid perovskite holds promise to achieve spin-dependent electrochemistry. However, conventional chiral 2D perovskites suffer from low conductivity and hygroscopicity, limiting electrochemical performance and operational stability. Here, a cutting-edge material design is introduced to develop a stable and efficient chiral perovskite-based spin polarizer by employing fluorinated chiral cation. The fluorination approach effectively promotes the charge carrier transport along the out-of-plane direction by mitigating the dielectric confinement effect within the multi-quantum well-structured 2D perovskite. Integrating the fluorinated cation incorporated spin polarizer with BiVO4 photoanode considerably boosts the photocurrent density while reducing overpotential through a spin-dependent oxygen evolution reaction. Furthermore, the hydrophobic nature of fluorine in spin polarizer endows operational stability to the photoanode, extending the durability by 280% as compared to the device with non-fluorinated spin polarizer.

Enhanced Phase Stability and Reduced Bandgap for CsPbI3 Perovskite through Bi3+ and Cl– Co-Doping

All-inorganic perovskite CsPbI3 is emerging as a thermally more stable alternative to organic-inorganic hybrid perovskites. However, CsPbI3 perovskite suffers from poor phase stability at ambient temperature, and its bandgap is a bit too large as light-harvesting materials in both single-junction and perovskite-on-silicon tandem solar cells. In this study, we propose an electrically neutral co-doping strategy that equimolar Bi3+ (occupying the Pb site) and Cl– (occupying the interstitial site) are incorporated into CsPbI3. Unlike the individual Bi3+ or Cl– doping, the neutral co-doping can avoid stimulating the formation of the detrimental native defects. Our first-principles calculations suggest that the co-doped systems are stable at ambient temperature and possess narrower bandgaps compared with the undoped CsPbI3. Moreover, the electron and hole states are spatially separated in these multiple-ion compounds.