Metal Organic Framework Thin Films Research Articles

Regulated Charge Transfer in Donor‐Acceptor Metal‐Organic Frameworks for Highly‐Sensitive Photodetectors

In photo‐induced charge separation, organic thin films with donor and acceptor chromophores are vital for uses such as artificial photosynthesis and photodetection. The main challenges include optimizing charge separation efficiency and identifying the ideal acceptor/donor ratio. Achieving this is difficult due to the variability in molecular configurations within these typically amorphous organic aggregates. Metal‐organic frameworks (MOFs) provide a structured solution by enabling systematic design of donor/acceptor blends with adjustable ratios within a crystalline lattice. We demonstrate this approach by incorporating donor and acceptor naphthalenediimide (NDI) chromophores as linkers in a highly oriented, monolithic MOF thin film. By adjusting the NDI acceptor linker concentration during the layer‐by‐layer assembly of surface‐anchored MOF thin films (SURMOFs), we significantly enhanced charge separation efficiency. Surprisingly, the optimum acceptor concentration was only 3%, achieving a forty‐fold increase in photodetection efficiency compared to baseline NDI donor‐based SURMOFs. This unexpected behaviour was clarified through theoretical analysis enabled by the well‐defined crystalline structure of the SURMOFs. Using density functional theory and kinetic Monte Carlo simulations, we identified two opposing effects from acceptors: the positive effect of suppressing undesirable charge carrier recombination is offset at high concentrations by a reduction in charge‐carrier mobility.

Regulated Charge Transfer in Donor-Acceptor Metal-Organic Frameworks for Highly-Sensitive Photodetectors.

In photo-induced charge separation, organic thin films with donor and acceptor chromophores are vital for uses such as artificial photosynthesis and photodetection. The main challenges include optimizing charge separation efficiency and identifying the ideal acceptor/donor ratio. Achieving this is difficult due to the variability in molecular configurations within these typically amorphous organic aggregates. Metal-organic frameworks (MOFs) provide a structured solution by enabling systematic design of donor/acceptor blends with adjustable ratios within a crystalline lattice. We demonstrate this approach by incorporating donor and acceptor naphthalenediimide (NDI) chromophores as linkers in a highly oriented, monolithic MOF thin film. By adjusting the NDI acceptor linker concentration during the layer-by-layer assembly of surface-anchored MOF thin films (SURMOFs), we significantly enhanced charge separation efficiency. Surprisingly, the optimum acceptor concentration was only 3%, achieving a forty-fold increase in photodetection efficiency compared to baseline NDI donor-based SURMOFs. This unexpected behaviour was clarified through theoretical analysis enabled by the well-defined crystalline structure of the SURMOFs. Using density functional theory and kinetic Monte Carlo simulations, we identified two opposing effects from acceptors: the positive effect of suppressing undesirable charge carrier recombination is offset at high concentrations by a reduction in charge-carrier mobility.

A Porphyrin-Based MOF Thin Film with Oriented Nanosheet Arrays for Optimizing a Nonlinear Optical Response.

Developing two-dimensional (2D) hybrid nanosheet arrays integrating inorganic and organic components is highly significant for third-order nonlinear optical (NLO) applications. Herein, an oriented 2D porphyrin-based MOF (ZnTPyP(Co)) thin film composed of vertically stacked ultrathin nanosheets was fabricated via the liquid-phase epitaxial (LPE) layer-by-layer (LBL) method. The prepared ZnTPyP(Co) thin film exhibits an outstanding third-order NLO response with a high third-order nonlinear susceptibility of ∼2.63 × 10-7 esu, which is ascribed to the hybrid nanosheet array structure. Additionally, experimental Z-scan measurement and theoretical calculations also demonstrate that the substitution of Co metal ions in the porphyrinic core can increase the level of delocalization of the porphyrinic group and contribute to the material's enhanced NLO properties. These findings not only provide new film candidates for NLO application but also highlight the potential of 2D MOF nanosheets in advanced optical devices.

Steering diffusion selectivity of chemical isomers within aligned nanochannels of metal-organic framework thin film

The movement of molecules (i.e. diffusion) within angstrom-scale pores of porous materials such as metal-organic frameworks (MOFs) and zeolites is influenced by multiple complex factors that can be challenging to assess and manipulate. Nevertheless, understanding and controlling this diffusion phenomenon is crucial for advancing energy-economic membrane-based chemical separation technologies, as well as for heterogeneous catalysis and sensing applications. Through precise assessment of the factors influencing diffusion within a porous metal-organic framework (MOF) thin film, we have developed a chemical strategy to manipulate and reverse chemical isomer diffusion selectivity. In the process of cognizing the molecular diffusion within oriented, angstrom-scale channels of MOF thin film, we have unveiled a dynamic chemical interaction between the adsorbate (chemical isomers) and the MOF using a combination of kinetic mass uptake experiments and molecular simulation. Leveraging the dynamic chemical interactions, we have reversed the haloalkane (positional) isomer diffusion selectivity, forging a chemical pathway to elevate the overall efficacy of membrane-based chemical separation and selective catalytic reactions.

Colorimetric Fabry-Pérot Sensor with Hetero-Structured Dielectric for Humidity Monitoring.

A full-color colorimetric humidity sensor with high brightness is proposed by using a hetero-structured dielectric film in a metal-insulator-metal (MIM) resonator. A humidity-responsive polymer is designed to graft on top of a metal-organic frameworks (MOFs) thin film (MOFs-Polymer) as insulator layer in the resonator. Programmable tuning of reflected color is achieved by controlling the polymer thicknesses, and finite difference time domain simulation of light-matter interactions at subwavelength scales proves the dependence of the reflected wavelength on dielectric layer thickness of the resonator. Vivid full-color changing is realized during tracking humidity process due to swelling of the stimuli-responsive polymer. Ultrafast response (≈0.75 s) is achieved for tracking trace H2O from H2O/methanol mixture, which is ≈104 faster than that of the pure polymer-based MIM resonator. Meanwhile, the study observes significant spectral redshift because the porous MOFs film facilitates the preconcentration of external stimulus and improves the detection sensitivity of the resonator. Further, double-channel anti-counterfeiting multiplexing imaging is devised on the MIM resonator by photomask technology. Patterned encoding for security label is achieved on the MIM resonator by engineering humidity-tunable pixels of Au/MOFs-Polymer/Au and humidity-invalid pixels of Au/MOFs/Au.

Two-Dimensional (2D) Conductive Metal-Organic Framework Thin Films: The Preparation and Applications in Electrochemistry.

Two-dimensional conductive MOF thin films have attracted attention due to their rich pore structure and unique electrical properties, and their applications in many fields, including batteries, sensing, supercapacitors, electrocatalysis, etc. This paper discusses several preparation methods for 2D conductive MOF thin films. And the applications of 2D conductive MOF thin films are summarized. In addition, the current challenges in the preparation of 2D conductive MOF thin films and the great potential in practical applications are discussed.

Fine-Scale Aerosol-Jet Printing of Luminescent Metal-Organic Framework Nanosheets.

Fabrication of metal-organic framework (MOF) thin films is an ongoing challenge to achieve effective device integration. Inkjet printing has been employed to print various luminescent metal-organic framework (MOF) films. Luminescent metal-organic nanosheets (LMONs), nanometer-thin particles of MOF materials with comparatively large micrometer lateral dimensions, provide an ideal morphology that offers enhancements over analogous MOFs in luminescent properties such as intensity and photoluminescent quantum yield. The morphology is also better suited to the formation of thin films. This work harnesses the preferential features of LMONs to access the advanced technique of aerosol-jet printing (AJP) to print luminescent films with precise geometries and patterns across the micrometer and centimeter length scales. AJP of LMONs exhibiting red (R), green (G), and blue (B) emission were studied systematically to reveal the increase of luminescence upon additive layering printing until a threshold was reached limited by self-quenching. By combining different LMON emitters, emission chromaticity and intensity were shown to be tunable, including the combination of RGB emitters to fabricate white-light-emitting films. A white-light LMON film was printed onto a UV light emitting diode (LED), producing a working white-light-emitting diode. Printing with multiple distinct photoluminescent inks produced intricate multicolor patterns that dynamically responded to excitation wavelength, acting either as micrometer-scale LED-type cells or larger visual tags. Collectively, the work offers an advancement for MOF thin films by printing MON materials using AJP, offering a precise method for manufacturing a wide range of critical functional devices, from luminescent sensors to optoelectronics, and more broadly even the opportunity for printed circuitry with conductive MONs.

Topochemical Polymerization at Diacetylene Metal-Organic Framework Thin Films for Tuning Nonlinear Optics.

Developing the topochemical polymerization of metal-organic frameworks (MOFs) is of pronounced significance for expanding their functionalities but is still a challenge on third-order nonlinear optics (NLO). Here, we report diacetylene MOF (CAS-1-3) films prepared using a stepwise deposition method and film structural transformation approach, featuring dynamic structural diversity. The MOF structures were determined by the three-dimensional electron diffraction (3D ED) method from nanocrystals collected from the films, which provides a reliable strategy for determining the precise structure of unknown MOF films. We demonstrate the well-aligned diacetylene groups in the MOFs can promote topological polymerization to produce a highly conjugated system under thermal stimulation. As a result, the three MOF films have distinct NLO properties: the CAS-1 film exhibits saturable absorption (SA) while CAS-2 and CAS-3 films exhibit reverse saturable absorption (RSA). Interestingly, due to the topochemical polymerization of the MOF films, a transition from SA to RSA response was observed with increasing temperatures, and the optical limiting effect was significantly enhanced (∼46 times). This study provides a new strategy for preparing NLO materials and thermally regulation of nonlinear optics.

Electrocatalysis in MOF Films for Flexible Electrochemical Sensing: A Comprehensive Review.

Flexible electrochemical sensors can adhere to any bendable surface with conformal contact, enabling continuous data monitoring without compromising the surface's dynamics. Among various materials that have been explored for flexible electronics, metal-organic frameworks (MOFs) exhibit dynamic responses to physical and chemical signals, offering new opportunities for flexible electrochemical sensing technologies. This review aims to explore the role of electrocatalysis in MOF films specifically designed for flexible electrochemical sensing applications, with a focus on their design, fabrication techniques, and applications. We systematically categorize the design and fabrication techniques used in preparing MOF films, including in situ growth, layer-by-layer assembly, and polymer-assisted strategies. The implications of MOF-based flexible electrochemical sensors are examined in the context of wearable devices, environmental monitoring, and healthcare diagnostics. Future research is anticipated to shift from traditional microcrystalline powder synthesis to MOF thin-film deposition, which is expected to not only enhance the performance of MOFs in flexible electronics but also improve sensing efficiency and reliability, paving the way for more robust and versatile sensor technologies.

Gd Metal-Organic Framework Thin Film for On-Chip Local Magnetic Refrigeration.

Dense metal-organic frameworks with high spin paramagnetic nodes are competitive materials for cryogenic magnetic refrigeration, particularly in applications for which local cooling is advantageous. We focus on obtaining thin films of gadolinium formate, which has a large volumetric magnetocaloric effect. Continuous and homogeneous deposits of gadolinium formate are successfully formed on silicon by means of aerosol jet printing, with control over the film thickness from 0.35 μm up to 2.5 μm. The excellent cooling power of the deposits is evidenced via direct measurements of the cooling of a 200 μm silicon wafer down to sub-K temperatures by a single demagnetization from 1 T and 2 K, thereby demonstrating the potential of this approach for on-chip local magnetic refrigeration.

Wrinkled metal-organic framework thin films with tunable Turing patterns for pliable integration.

Flexible integration spurs diverse applications in metal-organic frameworks (MOFs). However, current configurations suffer from the trade-off between MOF loadings and mechanical compliance. We report a wrinkled configuration of MOF thin films. We established an interfacial synthesis confined and controlled by a polymer topcoat and achieved multiple Turing motifs in the wrinkled thin films. These films have complete MOF surface coverage and exhibit strain tolerance up to 53.2%. The enhanced mechanical properties allow film transfer onto various substrates. We obtained membranes with large H2/CO2 selectivity (41.2) and high H2 permeance (8.46 × 103 gas permeation units), showcasing negligible defects after transfer. We also achieved soft humidity sensors on delicate electrodes by avoiding exposure to harsh MOF synthesis conditions. These results highlight the potential of wrinkled MOF thin films for plug-and-play integration.

Harmony through Order: Unveiling the Pivotal Role of Structural Precision in Assembling Phthalocyanines and Porphyrins

This presentation will focus on the strategic creation of 'Designer Solids' using chromophoric building blocks, in particular porphyrins and phthalocyanines. By employing the MOF-approach, suitable photoactive compounds are assembled into crystalline materials. Highlighted will be the latest advancements in the creation of MOF-based devices, covering a range of technologies such as electrochemical, photoelectrochemical, photovoltaic, and sensing applications, again emphasizing the use of porphyrin and phthalocyanine linkers. The talk will also explore the innovative use of internal interfaces in MOF heterostructures for enhanced photon upconversion and diode production.Addressing the challenge of forming stable and consistent electrical contacts with MOF materials, as well as producing high optical quality MOF thin films, we have developed a layer-by-layer (LbL) deposition technique [1] for crafting well-defined, highly oriented, and uniform MOF thin films on suitably prepared conductive and/or transparent surfaces. These films, known as SURMOFs, exhibit promising characteristics, particularly for optical uses [2]. We will detail the principles behind SURMOF construction and present findings from comprehensive studies on their electrical and photophysical behaviors, both in their original state and when their pores are filled with functional additives.[3,4] Additionally, the effects on band structure in crystalline porphyrin arrays constructed via the SURMOF method will be examined.[5]The lecture will also delve into further applications achieved by incorporating nanoparticles or quantum dots into MOFs, and the creation of molecular solids without inversion symmetry for second harmonic generation (SHG).[6]In the final segment, the suitability of SURMOFs for automated research methods will be discussed. Leveraging robotic systems governed by machine learning (ML) algorithms, we can effectively fine-tune thin film attributes such as orientation, crystallinity, and surface smoothness. [7,8] This aspect will be particularly emphasized in relation to the development of SURMOF-based sensor systems.

(Invited) Innovative MOF-Based Strategies for Assembling Chromophores: Perspectives for Next-Generation Organic Electronics

In the realm of organic electronics, such as photovoltaics, photodetectors, and light-emitting devices, the integration of organic chromophores into solid-state assemblies and their connection with electrodes is crucial. A notable development in this area is the use of metal-organic frameworks (MOFs), also referred to as the MOF method [1], which has been gaining traction. This approach involves using organic chromophores like anthracene and other planar aromatics, including Hexa-peri-hexabenzocoronene (HBC), equipped with coupling units, to create ditopic linkers that connect with metal-oxo nodes in MOFs. In view of the challenges of integrating MOF powders into devices, recent advancements have led to the development of layer-by-layer methods yielding high-quality, monolithic MOF thin films [2]. These films offer exceptional optical qualities and show, in many cases, a reduced density of defects.MOFs' periodic structures enable the deliberate design of chromophore assemblies, impacting optical absorption through inter-molecular interactions. This design approach has facilitated the creation of structures like J-aggregates, initially simulated in silico and later realized experimentally [3]. Additionally, MOFs enable the realization of band-structure phenomena, such as indirect band gaps [4], and chiroptical effects, including circularly polarized light emission [5] and the helical sensitivity in photodetectors [6].We've also explored lbl architectures for constructing heterostructures, useful in photon up-conversion applications. This involves leveraging MOFs' porous nature, as seen in the integration of C60 into SURMOF pores for applications like photoconductivity [7] and organic diodes [8]. Recent efforts have also focused on assembling non-centrosymmetric SURMOFs for nonlinear optical properties, demonstrating substantial second harmonic generation (SHG) activity [9].Our presentation will showcase key instances of successfully incorporating organic chromophores into SURMOFs for device fabrication, emphasizing the synergy with theoretical models. Given the vast number (> 120,000) of known MOFs, a theoretical approach is essential to guide experimental efforts efficiently.

Fabricating Large-Area Thin Films of 2D Conductive Metal-Organic Frameworks.

ConspectusRecent years have witnessed significant interest in two-dimensional metal-organic frameworks (MOFs) due to their unique properties and promising applications across various fields. These materials offer distinct advantages, including high porosity and excellent charge transport properties. Their tunability allows precise control over various factors, including the electronic structure adjustments and local reactivity modulation, facilitating a wide range of properties and applications, such as material sensing and spin dynamics control. Moreover, the precise crystal structure of 2D MOFs supports rational design and mechanism studies, providing insights into their potential applications and enhancing their utility in various scientific and technological endeavors.To fully unveil the latent capabilities of 2D MOFs and advance their applications across diverse fields, thin film synthesis is crucial. Thin films provide a platform for investigating the intrinsic electrical properties of 2D MOFs with anisotropic structures, enabling the exploration of their unique characteristics comprehensively. Additionally, thin films offer the advantage of minimizing interference at contacts and junctions, thereby enhancing the performance of 2D MOFs for various applications. Furthermore, the properties of thin films can vary with thickness, presenting an opportunity to tailor their characteristics based on specific requirements.In this Account, we present an overview of our research focusing on the synthesis of 2D conductive MOF thin films encompassing two primary methods: chemical vapor deposition and solution processing. The chemical vapor deposition method allows for one-step, all-vapor-phase processes resulting in MOFs with edge-on orientation, controllable film thicknesses ranging from 55 to 662.7 nm, and smooth, homogeneous surfaces. On the other hand, solution-processing introduces a novel MOF, Cu3(HHTATP)2, by reducing interlayer interactions through the addition of pendent Brønsted bases on a ligand, enabling spin coating for thin film synthesis. This method yields a concentrated 2D MOF solution, enabling spin coating for thin film synthesis, where reversible electrical conductivity changes occur through doping with an acid and dedoping with a base. Additionally, we discuss various other synthesis methods, such as interfacial synthesis, layer-by-layer assembly, and microfluidic-assisted synthesis, offering versatile approaches for fabricating large-area thin films with tailored properties. Finally, we address ongoing challenges and potential strategies for further advancement in 2D conductive MOF thin film synthesis. We hope that this Account provides insights for selecting synthesis methods tailored to specific purposes, contributes to the development of varied synthesis techniques, and facilitates the exploration of diverse applications, unlocking the full potential of 2D conductive MOFs for next-generation technologies.

Synthesis of UiO-66-Pyca-CuO by a Simple and Novel Method: MOF-based Metal Thin Film as Heterogeneous Catalysts for the Synthesis of α-Aminonitriles.

Metal-organic frameworks (MOFs), particularly UiO-66-NH2, are employed as catalysts in many industrial catalyst applications. As converting catalysts into thin film significantly increases their catalytic properties, we report a general approach to synthesizing MOF thin films (UiO-66-Pyca-CuO). First, functionalization of UiO-66-NH2 was done with 3-pyridine carboxaldehyde by the postsynthesis method, and then, UiO-66-Pyca was entangled on the surface of copper oxide nanoparticles with a modern strategy (MOF thin film). The morphology and structure of the synthesized UiO-66-Pyca-CuO were determined by using X-ray diffraction, Fourier transform infrared, field-emission scanning electron microscopy, energy-dispersive analysis of X-ray, inductively coupled plasma-mass spectrometry, elemental analyses of CHNOS, temperature-programmed desorption of ammonia, Brunauer-Emmett-Teller, and X-ray photoelectron spectroscopy. We studied the catalytic action of the UiO-66-Pyca-CuO thin film in the synthesis of α-aminonitriles via Strecker reaction. Our studies show that this catalysis can be a suitable catalyst in the synthesis of α-aminonitriles because of having advantages such as using the solvent being environmentally friendly, easy separation of the catalyst (only by picking up the MOF thin film from inside the solution), the reaction at room temperature, high yield, and reusability.

Electrical and Mechanical Controllability of Rotor Dynamics in MOF Thin Films Revealed by AFM-IR

Electrical and Mechanical Controllability of Rotor Dynamics in MOF Thin Films Revealed by AFM-IR

Solvothermal synthesis of Ni/Co-based metal-organic framework with nanosheets-like structure for high-performance supercapacitor

In the present investigation, we have successfully synthesized Ni/Co-based metal-organic framework thin films on stainless steel substrates via facile and low-cost solvothermal method using 1,4-benzenedicarboxylic acid as an organic linker. X-ray diffraction technique (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), and electrochemical studies have been used to characterize the Ni/Co-MOF electrode materials. The purity and crystallinity of Ni/Co-MOF thin films were studied with the help of XRD. FESEM images showed that Ni/Co-MOF thin films have a nanosheets-like morphology which is suitable for supercapacitor applications. The functional groups present in the sample were confirmed by Fourier Transform Infrared Spectroscopy. The electrochemical performance of Ni/Co-MOF coated stainless steel was studied in 1 M KOH electrolyte at various scan rates and current densities. The NiCo2-MOF material provides a specific capacitance of 1070 Fg−1 at the current density of 0.5 mA cm−2. Additionally, the NiCo2-MOF electrode exhibits an excellent energy density of 30.96 Wh kg−1 at a power density of 3.2 kW kg−1 and outstanding cyclic stability with 85 % retention after 5000 charge/discharge cycles. The results suggest that NiCo2-MOF offers excellent electrochemical performance and may be a potential candidate for supercapacitor application.

Enhancing the Quality of MOF Thin Films for Device Integration Through Machine Learning: A Case Study on HKUST‐1 SURMOF Optimization

AbstractMetal–organic Frameworks (MOFs), especially as thin films, are increasingly recognized for their potential in device integration, notably in sensors and photo detectors. A critical factor in the performance of many MOF‐based devices is the quality of the MOF interfaces. Achieving MOF thin films with smooth surfaces and low defect densities is essential. Given the extensive parameter space governing MOF thin film deposition, the use of machine learning (ML) methods to optimize deposition conditions is highly beneficial. Combined with robotic fabrication, ML can more effectively explore this space than traditional methods, simultaneously varying multiple parameters to improve optimization efficiency. Importantly, ML can provide deeper insights into the synthesis of MOF thin films, an essential area of research. This study focuses on refining an HKUST‐1 SURMOF (surface‐mounted MOF) to achieve minimal surface roughness and high crystallinity, including a quantitative analysis of the importance of the various synthesis parameters. Using the SyCoFinder ML technique, thin film surface quality is markedly enhanced in just three generations created by a genetic algorithm, covering 30 distinct parameter sets. This method greatly reduces the need for extensive experimentation. Moreover, the results enhance the understanding of the vast synthesis parameter space in HKUST‐1 SURMOF growth and broaden the applications of MOF thin films in electronic and optoelectronic devices.

Chiral Liquid Crystalline Metal-Organic Framework Thin Films for Highly Circularly Polarized Luminescence.

Combining metal-organic frameworks (MOFs) with liquid crystals to construct liquid crystalline MOFs (LCMOF) offers the advantage of endowing and enhancing their functionality, yet it remains a challenging task. Herein, we report chiral liquid crystalline MOF (CLCMOF) thin films by cross-linking the chiral liquid crystals (CLC) with MOF thin films to realize highly circular polarization luminescence (CPL) performance with photo and thermal switching. By layer by layer cross-linking stilbene-containing CLC with stilbene-based MOF (CLC/MOF) thin film, the CLCMOF thin films were successfully obtained after UV irradiation due to the abundant [2 + 2] photocycloaddition. The resulted CLCMOF thin films have strong chirality, obvious photochromic fluorescent, and strong CPL performance (the asymmetry factor reaches to 0.4). Furthermore, due to the photochromic fluorescent MOF and thermotropic CLC, the CPL can be reversed and red-shifted after heating and UV irradiation treatment, showing photo- and thermal CPL switching. Such MOF-based CPL thin films with photo/thermal CPL switching were prepared to patterns and codes for the demonstration of potential application in advanced information anticounterfeit and encryption. This study not only opens a strategy for developing chiral thin films combining MOFs and liquid crystals but also offers a new route to achieve CPL switching in optical applications.

Influence of Humidity on Layer-by-Layer Growth and Structure in Coordination Networks.

Metal-organic frameworks (MOFs) are promising materials because of their high designability of pores and functionalities. Especially, MOF thin films and their properties have been investigated toward applications in nanodevices. Typically, MOF thin films are fabricated by using a bottom-up method such as layer-by-layer (LbL) growth in air. Because the water molecules can coordinate and be replaced with organic linkers during synthesis, humidity conditions will be expected to influence the LbL growth processes. In this study, we fabricated MOF thin films composed of Zn2+, tetrakis-(4-carboxyphenyl)-porphyrin (TCPP), and 4,4'-bipyridyl (bpy) at 10 and 40% relative humidity (RH) conditions. Then, we investigated the humidity effects on chemical compositions of TCPP and bpy, periodic structure, orientation, and surface morphology. At high RH, coordination replacement of water with the organic linkers becomes more competitive than that at low RH, resulting in a different TCPP/bpy composition ratio between the two RH conditions. Also, more frequent coordination replacements of water with the organic linkers at high RH led to the formation of phases other than that observed at low RH, loss of growth orientation, and rough surface. The findings clarified the importance of controlling the RH condition during LbL growth to obtain the desired coordination networks.