Colorless to black switching with high contrast ratio via the electrochemical process of a hybrid organic-inorganic perovskite

Colorless‐to‐black switching has attracted widespread attention for smart windows and multifunctional displays because they are more useful to control solar energy.However,it still remains a challenge owing to the tremendous difficulties in the design of completely reverse absorptions in transmissive and colored states.Herein,we report on an electrochemical device that can switch between colorless and black by using the electrochemical process of hybrid organic–inorganic perovskite MAPbBr_(3),which shows a high integrated contrast ratio of up to 73%from 400 to 800 nm.The perovskite solution can be used as the active layer to assemble the device,showing superior transmittance over the entire visible region in neutral states.By applying an appropriate voltage,the device undergoes reversible switching between colorless and black,which is attributed to the formation of lead and Br_(2)in the redox reaction induced by the electron transfer process in MAPbBr_(3).In addition,the contrast ratio can be modulated over the entire visible region by changing the concentration and the applied voltage.These results contribute toward gaining an insightful understanding of the electrochemical process of perovskites and greatly promoting the development of switchable devices.

Ferroelectric Properties and Applications of Hybrid Organic-Inorganic Perovskites

Hybrid organic-inorganic perovskites （e.g. CH;NH;PbI;） have attracted tremendous attention due to their promise for achieving next-generation cost-effective and high performance optoelectronic devices.These hybrid organic-inorganic perovskites possess excellent optical and electronic properties, including strong light absorption, high carrier abilities, optimized charge diffusion lengths, and reduced charge recombination etc., leading to their widespread applications in advanced solar energy technologies （e.g.high efficiency perovskite solar cells）. However, there is still a lack of investigations regarding fundamental properties such as ferroelectricity in these perovskites.As conventional ferroelectric ceramics are prepared at high temperature and have no mechanically flexibility,low-temperature proceed and flexible perovskite ferroelectrics have become promising candidates and should be exploited for future flexible ferroelectric applications. Here, ferroelectric properties in hybrid organic-inorganic perovskites and several state-of-the-art perovskite ferroelectrics are reviewed. Novel ferroelectric applications of hybrid organic-inorganic perovskites are discussed as well, providing guideline for realizing future high performance and flexible ferroelectric devices.

Anion storing,oxygen vacancy incorporated perovskite oxide composites for high-performance aqueous dual ion hybrid supercapacitors

Dual ion storage hybrid supercapacitors(HsCs)are considered as a promising device to overcome the limited energy density of existing supercapacitors while preserving high power and long cyclability.However,the development of high-capacity anion-storing materials,which can be paired with fast charg-ing capacitive electrodes,lags behind cation-storing counterparts.Herein,we demonstrate the surface faradaic OH-storage mechanism of anion storing perovskite oxide composites and their application in high-performance dual ion HsCs.The oxygen vacancy and nanoparticle size of the reduced LaMnO_(3)(r-LaMnO_(3))were controlled,while r-LaMnO_(3) was chemically coupled with ozonated carbon nanotubes(oCNTs)for the improved anion storing capacity and cycle performance.As taken by in-situ and ex-situ spectroscopic and computational analyses,OH-ions are inserted into the oxygen vacancies coordi-nating with octahedral Mn with the increase in the oxidation state of Mn during the charging process or vice versa.Configuring OH-storing r-LaMnO_(3)/oCNT composite with Na*storing MXene,the as-fabricated aqueous dual ion HSCs achieved the cycle performance of 73.3%over 10,000 cycles,delivering the max-imum energy and power densities of 47.5 w h kg^(-1) and 8 kw kg^(-1),respectively,far exceeding those of previously reported aqueous anion and dual ion storage cells.This research establishes a foundation for the unique anion storage mechanism of the defect engineered perovskite oxides and the advancement of dual ion hybrid energy storage devices with high energy and power densities.

Enhanced Redox Electrocatalysis in High‑Entropy Perovskite Fluorides by Tailoring d–p Hybridization

High-entropy catalysts featuring exceptional properties are,in no doubt,playing an increasingly significant role in aprotic lithium-oxygen batteries.Despite extensive effort devoted to tracing the origin of their unparalleled performance,the relationships between multiple active sites and reaction intermediates are still obscure.Here,enlightened by theoretical screening,we tailor a high-entropy perovskite fluoride(KCoMnNiMgZnF_(3)-HEC)with various active sites to overcome the limitations of conventional catalysts in redox process.The entropy effect modulates the d-band center and d orbital occupancy of active centers,which optimizes the d–p hybridization between catalytic sites and key intermediates,enabling a moderate adsorption of LiO_(2)and thus reinforcing the reaction kinetics.As a result,the Li–O2 battery with KCoMnNiMgZnF_(3)-HEC catalyst delivers a minimal discharge/charge polarization and long-term cycle stability,preceding majority of traditional catalysts reported.These encouraging results provide inspiring insights into the electron manipulation and d orbital structure optimization for advanced electrocatalyst.

Research progress on hybrid organic-inorganic perovskites for photo-applications

Hybrid organic-inorganic perovskite materials have attracted significant atte ntion of most re searchers in recently years,which is ascribed to the superior photoelectric properties,such as the suitable band gaps for harvesting sunlight,and exhibit high optical adsorption,high charge-carrier lifetimes and long diffusion lengths.The photodetectors,light-emitting diodes,solar cells and photocatalysts represent the remarkable applications for the hybrid organic-inorganic perovskite materials.Herein,we review the recent progress of hybrid organic-inorganic perovskite-based photodetectors,light-emitting diodes,solar cells and photocatalysts.The challenges and outlook for the hybrid organic-inorganic perovskitebased photodetectors,light-emitting diodes,solar cells and photocatalysts are considered.

Organic-inorganic halide perovskites for memristors

Organic-inorganic halides perovskites(OHPs)have drawn the attention of many researchers owing to their astonishing and unique optoelectronic properties.They have been extensively used for photovoltaic applications,achieving higher than 26%power conversion efficiency to date.These materials have potential to be deployed for many other applications beyond photovoltaics like photodetectors,sensors,light-emitting diodes(LEDs),and resistors.To address the looming challenge of Moore’s law and the Von Neumann bottleneck,many new technologies regarding the computation of architectures and storage of information are being extensively researched.Since the discovery of the memristor as a fourth component of the circuit,many materials are explored for memristive applications.Lately,researchers have advanced the exploration of OHPs for memristive applications.These materials possess promising memristive properties and various kinds of halide perovskites have been used for different applications that are not only limited to data storage but expand towards artificial synapses,and neuromorphic computing.Herein we summarize the recent advancements of OHPs for memristive applications,their unique electronic properties,fabrication of materials,and current progress in this field with some future perspectives and outlooks.

Giant magneto field effect in up-conversion amplified spontaneous emission via spatially extended states in organic-inorganic hybrid perovskites

Up-conversion lasing actions are normally difficult to realize in light-emitting materials due to small multi-photon absorp-tion cross section and fast dephasing of excited states during multi-photon excitation.This paper reports an easily ac-cessible up-conversion amplified spontaneous emission(ASE)in organic-inorganic hybrid perovskites(MAPbBr3)films by optically exciting broad gap states with sub-bandgap laser excitation.The broad absorption was optimized by adjust-ing the grain sizes in the MAPbBr3 films.At low sub-bandgap pumping intensities,directly exciting the gap states leads to 2-photon,3-photon,and 4-photon up-conversion spontaneous emission,revealing a large optical cross section of multi-photon excitation occurring in such hybrid perovskite films.At moderate pumping intensity(1.19 mJ/cm2)of 700 nm laser excitation,a significant spectral narrowing phenomenon was observed with the full width at half maximum(FWHM)de-creasing from 18 nm to 4 nm at the peak wavelength of 550 nm,simultaneously with a nonlinear increase on spectral peak intensity,showing an up-conversion ASE realized at low threshold pumping fluence.More interestingly,the up-con-version ASE demonstrated a giant magnetic field effect,leading to a magneto-ASE reaching 120%.In contrast,the up-conversion photoluminescence(PL)showed a negligible magnetic field effect(<1%).This observation provides an evid-ence to indicate that the light-emitting states responsible for up-conversion ASE are essentially formed as spatially exten-ded states.The angular dependent spectrum results further verify the existence of spatially extended states which are polarized to develop coherent in-phase interaction.Clearly,using broad gap states with spatially extended light-emitting states presents a new approach to develop up-conversion ASE in organic-inorganic hybrid perovskites.

Recent advances in atomic imaging of organic-inorganic hybrid perovskites

Three-dimensional organic-inorganic hybrid perovskites(OHPs)hold a great prospect for photovoltaic applications due to their outstanding electronic and optical properties.These fascinating properties of OHPs in combination with their scalable and low-cost production make OHPs promising candidates for next-generation optoelectronic devices.The ability to obtain atomistic insights into physicochemical properties of this class of materials is crucial for the future development of this field.Recent advances in various scanning probe microscopy techniques have demonstrated their extraordinary capability in real-space imaging and spectroscopic measurements of the structural and electronic properties of OHPs with atomic-precision.Moreover,these techniques can be combined with light illumination to probe the structural and optoelectronic properties of OHPs close to the real device operation conditions.The primary focus of this review is to summarize the recent progress in atomic-scale studies of OHPs towards a deep understanding of the phenomena discovered in OHPs and OHP-based optoelectronic devices.

Synthesis and Characterization of Layered Perovskite-type Organic-inorganic Hybrids(CnH2n+1NH3)2(CH3NH3)m-1PbmI3m+1(n=5-10,m=1,2)

Layered organic-inorganic hybrids（CnH2n＋1NH3）2（CH3NH3）m-1PbmI3m＋1 containing monolayer（m=1） and bilayer（m=2） perovsikte were synthesized by reactions in solution.The influences of the reactant ratio,solvent,reaction temperature,and reaction time on the structures of the products were investigated.The structures and the properties of the hybrids were characterized using X-ray diffraction（XRD）,scanning electron microscopy（SEM）,and ultraviolet and visible（UV） absorption spectroscopy.The XRD patterns and the SEM images demonstrate that the pure bilayer perovskite hybrids are obtained.The UV-vis spectra indicate that the number of the inorganic perovskite layer（m） has greater impact on the band gap than the number of the carbon atoms（n）.The band gap of bilayer hybrids（around 1.9 eV） is significantly less than that of monolayer hybrids（around 2.2 eV）.

Impact of Structural Disorder on Excitonic Behaviors and Dynamics in 2D Organic-Inorganic Hybrid Perovskites

Two thin-film 2 D organic-inorganic hybrid perovskites,i.e.,2-phenylethylammonium lead iodide(PEPI)and 4-phenyl-1-butylammonium lead iodide(PBPI)were synthesized and investigated by steady-state absorption,temperature-dependent photoluminescence,and temperature-dependent ultrafast transient absorption spectroscopy.PBPI has a longer organic chain(via introducing extra ethyl groups)than PEPI,thus its inorganic skeleton can be distorted,bringing on structural disorder.The comparative analyses of spectral profiles and temporal dynamics revealed that the greater structural disorder in PBPI results in more defect states serving as trap states to promote exciton dynamics.In addition,the fine-structuring of excitonic resonances was unveiled by temperature-dependent ultrafast spectroscopy,suggesting its correlation with inorganic skeleton rather than organic chain.Moreover,the photoexcited coherent phonons were observed in both PEPI and PBPI,pointing to a subtle impact of structural disorder on the low-frequency Raman-active vibrations of inorganic skeleton.This work provides valuable insights into the optical properties,excitonic behaviors and dynamics,as well as coherent phonon effects in 2 D hybrid perovskites.

A hybrid organic-inorganic perovskite with robust SHG switching

Owing to the diversity of structure and potential applications in the field of electrics,sensors,and light-emitting diodes,lead halide perovskites have attracted great attention in recent years.Especially those lead halide perovskites with non-centrosymmetric crystal structures usually exhibit nonlinear optical(NLO) characteristics,which may endow them photoelectricity switching functionality.In this work,a lead-based hybrid organic-inorganic perovskite(HOIP) material,trimethyliodomethylammonium lead trichloride(TMIM·PbCl_(3)),is obtained on the basis of tetramethylammonium lead chloride through halogen substitution on the cation part.It shows dual-phase-transition behavior around 345 and 358 K, which is significantly improved.TMIM·PbCl_(3)crystallizes in the chiral space group,P2_(1)2_(1)2_(1), and shows a welldefined second harmonic generation(SHG) response,and good switching endurance,which makes it an excellent candidate for SHG switching material.This work highlights the importance of halogen substitution for crystal engineering and may pave way for the further exploration of the optoelectronic devices.

Synthesis and Characterization of Layered Perovskite-type Organic-inorganic Hybrids (R-NH_3)_2(CH_3NH_3)Pb_2I_7

Layered organic-inorganic hybrids containing bilayer perovsikte （R-NH3）2（CH3NH3）Pb2I7 （where R=C12H25,C6H5C2H4） were synthesized by reactions in solution. The influences of the solvents and the reactant ratio on the structures of the products were investigated. The structures and the properties of the hybrids were characterized using X-ray diffraction （XRD） and ultraviolet and visible （UV） adsorption spectra. For comparing with the bilayer perovskite hybrids in structure and band gap magnitude, the hybrids containing monolayer perovskite （R-NH3）2PbI4 were also synthesized and characterized. The results demonstrate that the thickness of inorganic layer has obvious effect on the tunneling magnitude of the band gap but the organic part can be micro actuator of band gap.

Fabrication of branch-like Aph@LDH-MgO material through organic-inorganic hybrid conjugation for excellent anti-corrosion performance

Layered double hydroxides(LDH)frameworks have shown significant enhancement in stability and reusability,and their tailorable architecture brings new insight into the development of the next generation of hybrid materials,which attracted considerable attention in many fields over the years.One of the factors contributing to the widespread applicability of layered double hydroxides is their adaptable composition,which can accommodate a wide spectrum of potential anionic guests.This exceptional property makes the LDH system simple to adjust for various applications.However,most LDH systems are synthesized in situ in an autoclave at high temperatures and pressures that severely restrict the industrial use of such coating systems.In this study,LDH was directly synthesized on a magnesium alloy that had undergone plasma electrolytic oxidation(PEO)treatment in the presence of ethylenediaminetetraacetic acid,thereby avoiding the use of hydrothermal autoclave conditions.This LDH system was compared with a hybrid architecture consisting of organic-inorganic self-assembly.An organic layer was fabricated on top of the LDH film using 4-Aminophenol(Aph)compound,resulting in a smart hierarchical structure that can provide a robust Aph@LDH film with excellent anti-corrosion performance.At the molecular level,the conjugation characteristics and adsorption mechanism of Aph molecule were studied using two levels of theory as follows.First,Localized orbit locator(LOL)-πisosurface,electrostatic potential(ESP)distribution,and average local ionization energy(ALIE)on the molecular surface were used to highlight localization region,reveal the favorable electrophilic and nucleophilic attacks,and clearly explore the type of interactions that occurred around interesting regions.Second,first-principles based on density functional theory(DFT)was applied to study the hybrid mechanism of Aph on LDH system and elucidate their mutual interactions.The experimental and computational analyses suggest that the highπ-electron density and delocalization characteristics of the functional groups and benzene ring in the Aph molecule played a leading role in the synergistic effects arising from the combination of organic and inorganic coatings.This work provides a promising approach to design advanced hybrid materials with exceptional electrochemical performance.

Structural phase transition in a new organic-inorganic hybrid post-perovskite:(N,N-dimethylpyrrolidinium)[Mn(N(CN)_(2))_(3)]

In the realm of molecular phase transition research,particularly for applications in sensors,data storage and switching technologies,the role of organic-inorganic hybrid perovskite materials has been increasingly recognized for their significant potential.Nevertheless,hybrid post-perovskites,as a critical subclass of perovskites,have not been thoroughly studied and mainly limit in the instances based on polyatomic bridging agents like dicyanamide(dca^(-))and non-cyclic organic cations.Herein,a polar cyclic quaternary ammonium cation,N,N-dimethylpyrrolidinium(DMP^(+)),was used to assemble a new hybrid post-perovskite,(DMP)[Mn(dca)_(3)](1),which undergoes a phase transition from orthorhombic Bmmb to monoclinic P2_(1)/n space group at 249 K.By employing multiple techniques such as differential scanning calorimetry,variable-temperature single-crystal X-ray analysis,dielectric measurements,and Hirshfeld surface analysis,we disclosed the role of polar cyclic quaternary ammonium DMP^(+)in elevating the phase-transition temperature by 48 K,generating significant dielectric switching effect and facilitating interlayer sliding of inorganic framework.

Synthesis and characterization of hybrid organic-inorganic materials based on EA-MAn-APTES and silica

Poly (EA-MAn-APTES)/silica hybrid materials were successfully prepared fromEthyl acrylate (EA), maleic anhydride (MAn) and tetraethoxysilane (TEOS) in the presence of acoupling agent 3-aminopropyltriethoxysilane (APTES),by free-radical solution polymerization and insitu sol-gel process. The mass fraction of TEOS varied from 0 to 25%. The hybrid materials werecharacterized by the methods of FT-IR spectra, solvent extraction, scanning electron microscope (SEM), transmission electron microscope (TEM), differential scanning calorimetry (DSC) andthermogravimetric analysis (TGA) measuring apparatus to get their structures, gel contents,morphologies, particle sizes and thermal performances. The results show that the covalent bonds arebetween organic and inorganic phases, gel contents in the hybrid materials are much higher, theSiO_2 phase is well dispersed in the polymer matrix, silicon dioxide exist at nanoscale in thecomposites and have excellent thermal stability.

Effect of cerium ion(Ⅲ) on corrosion resistance of organic-inorganic hybrid coating on surface of aluminum-tube used in refrigeration equipment

Organic?inorganic hybrid coating on the surface of aluminum-tube used in refrigeration equipment using cerium ion (III) as the additive was fabricated by sol?gel method, and the structure of the coating was confirmed by FT-IR. The results of the characterization show that the corrosion resistance of the coating with 1.5 mmol/L cerium ion (III) gains significant improvement, in which the colour retention time of CuSO4 extends to 500 s, the anti-acid and alkali corrosion rates reduce by 67% and 70% compared with the blank one, respectively, and the salt spray tests also show good corrosion resistance. The electrochemical tests demonstrate that the self-corrosion current density and potential of the sample with hybrid coating are about 2.877×10?7 A/cm2 and?0.550 V, respectively. The metallographic and SEM images show that the hybrid coating is uniform and dense, and the EDS analysis confirms that the coating is mainly composed of Al, Si and Ce elements.

Synthesis and Characterization of Poly(St-co-BA) Latex with an Organic-Inorganic Hybrid Compound as Emulsifier

A poly (St-co-BA) latex was successfully synthesized by using an organic-inorganic hybrid compound (OIHC), an aliphatic carboxylate sodium/nano-silica composite, as the emulsifier, and investigated by particle size analyzer, transmission electron microscope (TEM), optical contact angle measurement (OCA) and dynamic mechanical analyzer (DMA). It was found that the protective agent, sodium polyacrylate (PA),could obviously improve the polymerization stability and the functional monomer, glycidyl methacrylate (GMA), could enhance the store stability of the latex. The particle size of poly(St-co-BA) latex decreased and then leveled off as OIHC content increased. TEM shows that the prepared polymers were actually organic-inorganic nanocomposites, and these films have better waterproof property than those prepared by traditional poly(St-co-BA) latex or organic silicone modified poly(St-co-BA) latex. The nanocomposite polymer has much higher glass transition temperature than organic silicone modified poly(St-co-BA) polymer containing the same organic silicone content.

Syntheses and Characterizations of Two New Organic-inorganic Hybrids Based on Heteropolymolybdates and Piperidine Molecules

Two new organic-inorganic compounds [（CH2）5NH2]3[PMo12O40]·3[（CH2）NH] 1 and [（CH2）5NH2]6[P2Mo18O62]·5H2O 2 have been synthesized using conventional and hydrothermal methods, respectively, and characterized by elemental analyses, IR, TG and single-crystal X-ray diffraction. X-ray analyses show that in these compounds heteropolymolybdates [PMo12O40]^3- and [P2Mo18O62]^6- are reserved their Keggin or Dawson structures and linked to piperidine through electrostatic and hydrogen-bonding interactions.

Simple hybrid dithiafulvenes-triphenylamine systems as dopant-free hole-transporting materials for efficient perovskite solar cells

Two extended hybrid conjugated systems based on a triphenylamine(TPA) core with two and three peripheral 1,4-dithiafulvenes(DTF) units coded WH-2 and WH-3 as hole-transporting materials(HTMs) applied in perovskite solar cells(PSCs) are synthesized by facile one-step reaction in good yield over 75%. DTF unit as electron donor can enhance the electron donating ability and the fusion of benzenic ring of TPA with DTF unit may lead to reinforced intermolecular interactions in the solid state. In addition,WH-2 and WH-3 exhibit a pyramid shape containing partial planarity and quasi three-dimensionality features, which is also conducive to enhancing the π-π stacking of molecules in the solid state. The above-mentioned structural characteristics make the two HTMs have good hole mobilities. As a result,WH-2 and WH-3 obtained the high intrinsic hole mobilities of 4.69 × 10^(-4)and 2.18 × 10^(-3)cm^(2)V^(-1)s^(-1)respectively. Finally, the power conversion efficiencies(PCEs) of PSCs with WH-2 and WH-3 as cost-effective dopant-free HTMs are 15.39% and 19.22% respectively and the PCE of PSC with WH-3 is on a par with that of PSC with Li-TFSI/t-BP doped Spiro-OMe TAD(19.67%).

Preparation of polythiophene/WO_3 organic-inorganic hybrids and their gas sensing properties for NO_2 detection at low temperature

Polythiophene/WO3（PTP/WO3）organic-inorganic hybrids were synthesized by an in situ chemical oxidative polymerization method,and char- acterized by X-ray diffraction（XRD）,transmission electron microscopy（TEM）and thermo-gravimetric analysis（TGA）.The Polythiophene/ WO3 hybrids have higher thermal stability than pure polythiophene,which is beneficial to potential application as chemical sensors.Gas sensing measurements demonstrate that the gas sensor based on the Polythiophene/WO3 hybrids has high response and good selectivity for de- tecting NO2 of ppm level at low temperature.Both the operating temperature and PTP contents have an influence on the response of PTP/WO3 hybrids to NO2.The 10 wt%PTP/WO3 hybrid showed the highest response at low operating temperature of 70-C.It is expected that the PTP/WO3 hybrids can be potentially used as gas sensor material for detecting the low concentration of NO2 at low temperature.