Bicontinuous Network Research Articles

Controlling spherulitic structures at surface and sub-layer of hollow fiber membranes prepared using nucleation agents via triple-orifice spinneret in TIPS process

In this study, the growth of a spherulitic structure at the surface and sub-layer of the polyvinylidene fluoride (PVDF) hollow fiber membrane was controlled by co-extruding nucleation agent (NA) solutions as the outermost layer of a triple-orifice spinneret in the thermally induced phase separation (TIPS) process. Using this method, the spherulites were tailored to be a variety of morphologies having different combinations with the bi-continuous network at the membrane surface and sub-layer, while the bulk membrane structure remained almost unchanged. These typically tailored spherulitic structures dramatically enhanced the surface roughness, hydrophobicity, liquid entry pressure, and permeation stability of the TIPS-prepared PVDF hollow fiber membranes. The experimental results from the pressure-driven filtration and the direct contact membrane distillation demonstrated great potential of the tailored membranes to achieve water treatment and seawater desalination. The electrostatic interaction between NA and PVDF played a key role in tailoring the special membrane spherulite structures, providing new possibilities for engineering TIPS-prepared hollow fiber membranes with desirable structures and performances to address current and future water shortages.

Super-hydrophobic poly (lactic acid) by controlling the hierarchical structure and polymorphic transformation

Focus on the design and execution of super-hydrophobic strategies, the phase control methodology, that is, solvent-volatilization and crystallization induced phase separation at low temperature (−15 °C), is proposed to construct three dimension (3D) poly(lactic-acid) (PLA) porous structures, denser stereo-complexed crystals (SCs) protrusions and bi-continuous SCs fibrillary networks in poly(L-lactic acid)/poly(D-lactic acid) (PLLA/PDLA) blends for the first time. We show that generating hierarchical structures are keys to enable the super-hydrophobicity, instead of traditionally adding fillers. By comparing the interfacial configurations of PLA pores with different PDLA content, it is shown that numerous SCs protrusions on the skeleton of 3D pores with 30% PDLA, especially for the bi-continuous SCs fibrillary networks with 50% PDLA, very different from the porous morphology of pure PLLA. The controllable PLA chains sharply facilitate the formation of SCs protrusions by the hydrogen bonding, which give rise to the limited time to growth ordered and large-sized lamellae. Of particular interests are our first establishments of developing uniform SCs protrusions on the internal 3D porous skeleton and multi-scale 3D fibrillary network structure for stereo-complex PLA, which afford the inner hydrophobic coincidence with the surface even after processed one-hour (1 h) by ultrasound in water. Therefore, we hypothesize that the key factor influencing super-hydrophobicity of the PLLA/PDLA films are 3D pores and bi-continuous SCs fibrillary networks combined with the roughly crystalline surface structure resembling rugged protrusions, leading to the water contact angle (CA) up to 155°. Moreover, the icing-resistance and thermal degradation behavior are highly obvious. This work firstly pave the way to polymer-derived networks with combination of self-constructed crystallization protrusions and bi-continuous 3D fibrillary network structure by hydrogen bonding for elegant implementation of super-hydrophobic characteristics other than the traditional addition of fillers.

Mesoscale bicontinuous networks in self-healing hydrogels delay fatigue fracture

Load-bearing biological tissues, such as muscles, are highly fatigue-resistant, but how the exquisite hierarchical structures of biological tissues contribute to their excellent fatigue resistance is not well understood. In this work, we study antifatigue properties of soft materials with hierarchical structures using polyampholyte hydrogels (PA gels) as a simple model system. PA gels are tough and self-healing, consisting of reversible ionic bonds at the 1-nm scale, a cross-linked polymer network at the 10-nm scale, and bicontinuous hard/soft phase networks at the 100-nm scale. We find that the polymer network at the 10-nm scale determines the threshold of energy release rate G0 above which the crack grows, while the bicontinuous phase networks at the 100-nm scale significantly decelerate the crack advance until a transition Gtran far above G0 In situ small-angle X-ray scattering analysis reveals that the hard phase network suppresses the crack advance to show decelerated fatigue fracture, and Gtran corresponds to the rupture of the hard phase network.

Bicontinuous network of electron donor-acceptor composites achieved by additive-free sequential deposition for efficient polymer solar cells

We report that sequential deposition of a highly crystalline polymer donor and a soluble fullerene acceptor leads to a well-defined interpenetrating network and enhanced power conversion efficiencies in bilayer polymer solar cells. Even without the use of solvent additives, layered thin films of poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3‴-di(2-octyldodecyl)-2,2’; 5′,2’’; 5″,2‴-quaterthiophen-5,5‴-diyl)] (PffBT4T-2OD) and [6,6]-phenyl C71-butyric acid methyl ester (PC71BM), as electron donor and acceptor materials, respectively, showed bicontinuous networks similar to those of a PffBT4T-2OD:PC71BM bulk-heterojunction (BHJ) thin film processed with 1,8-diiodooctane (DIO) as a solvent additive. Transmission electron microscopy results confirmed the BHJ-like morphology of the bilayered PffBT4T-2OD/PC71BM thin films. Bilayer solar cells fabricated without the DIO additive produced a power conversion efficiency of η ≈ 7.65%, which is even higher than that of a BHJ solar cell fabricated with the DIO additive (η ≈ 7.04%). These results demonstrate that a highly crystalline polymer donor and an electron-accepting small molecule can be a good combination for efficient bilayer polymer solar cells.

Electrode Design for High-Performance Sodium-Ion Batteries: Coupling Nanorod-Assembled Na3V2(PO4)3@C Microspheres with a 3D Conductive Charge Transport Network.

As one of the most promising cathodes for sodium-ion batteries, the polyanionic compounds still suffer from unsatisfactory capacity and rate performance resulting from poor electron conductivity. Furthermore, the charge-transfer kinetics, especially for Na+, becomes limiting as the mass loading increases. Herein, a robust free-standing electrode coupling optimal porous Na3V2(PO4)3@C microspheres with a bicontinuous charge transport network is designed and prepared by a simple casting method. In the design, the optimal porous carbon-coated microspheres, composed of some continuous nanorods, along with interwoven carbon nanofiber networks offer efficient electron transport and facile ion diffusion. Such an elaborate design enables impressive electron/ion conductivity, contributing to remarkable rate performance (116.1 mA h g-1 at 0.2 C; 96 mA h g-1 at 30 C) and outstanding cycling stability (90% capacity retention in 500 cycles at 1 C; 80% capacity retention in 5000 cycles at 10 C), which has surpassed other similar Na3V2(PO4)3-based free-standing electrodes as reported. More importantly, when mass loading extends to 8 mg cm-2, an excellent capacity retention of 75% at 10 C can be obtained. The research offers a new avenue into the rational design of porous microspheres electrode with high conductive charge transport network, indicating its superiority in practical applications.

Gelation mechanism and network structure of mixed kappa carrageenan/lambda carrageenan gels studied by macroscopic and microscopic observation methods

Dynamic rheology and particle tracking experiments were carried out to investigate the gelation mechanism and network structure of mixed κ-carrageenan (KC) and λ-carrageenan (LC) gels on the macroscopic and microscopic levels. Mixtures of KC and LC (total carrageenan concentration = 1.5%, K+ concentration = 15 mM) were prepared at different mixing ratios. The storage modulus (G′) was highest for pure KC and decreased monotonously with decreasing KC content. The mean square displacement (MSD) of probe particles was used to characterize the network on cooling and after one day of storage. On cooling, a single step decrease in the ensemble-averaged MSD was observed, in agreement with the rheological measurements. Time-averaged MSD values of individual particles showed a large distribution after one day in storage, especially for gels with low content of KC. This heterogeneity reflects microstructural heterogeneity, suggesting phase separation into KC-rich and LC-rich domains. Individual particle MSD values showed a bimodal distribution. The MSD could be described as a power-law, MSD~τα, with τ the lag time. The exponent α also showed a bimodal distribution. These findings suggest that two groups of probe particles with distinctly different mobilities are present in the mixed gels with particles of higher and lower mobilities present in the LC-rich and KC-rich phases. Based on the rheological results, as well as the particle tracking experiments, we propose that mixtures of KC and LC separate into a continuous phase and a non-continuous filler phase, with the continuous phase being made up of the more concentrated carrageenan. When the concentrations of the two carrageenans are roughly equal, we suggest that a bicontinuous phase-separated network is formed.

Construction of advanced 3D Co3S4@PPy nanowire anchored on nickel foam for high-performance electrochemical energy storage

Rational designed electrodes with high electron and ion diffusion capability is of great significant for the high-performance energy storage devices. Herein, the 3D Co3S4@PPy nanowires anchored on nickel foam (NF) was fabricated by a facile hydrothermal route and followed polymerization process. The vertically aligned Co3S4 nanowires are uniformly anchored on the NF struts without obvious aggregation, while the PPy is tightly encapsulated on the Co3S4 surface with a fluffy and porous structure. Therefore, the Co3S4@PPy hybrid electrode with bi-continuous conductive networks, NF struts and PPy coating layer, and porous PPy coating layer can facilitate electrons transfer as well as decrease electrolyte ions diffusion pathway. This hybrids as the electrochemical electrode exhibit the battery-type behavior, and an ultrahigh specific capacity of 723 C g−1, good rate capability and excellent cycling durability (98.6% retention after 1000 cycles) can be achieved. Moreover, the asymmetric two-electrode devices assembled by the Co3S4@PPy and active carbon (AC) can deliver a high practical performance in aqueous system. The material design strategy would provide an efficient way to develop high-performance energy storage devices.

Photophysics, morphology and device performances correlation on non-fullerene acceptor based binary and ternary solar cells

Abstract Non-fullerene acceptor (NFA) based organic solar cells (OSCs) are of high efficiency and low energy loss and low recombination features, which is owing to the advantage of non-fullerene acceptors. The photophysics investigation of non-fullerene solar cells, in comparing to fullerene based analogue as well as mixed acceptor ternary blends could help to understand the working mechanism of NFA functioning mechanism. We choose PBDB-T donor, the fullerene derivative PC71BM acceptor, and the non-fullerene acceptor ITIC as the model system, to construct binary and ternary solar cells, which then subject to ultrafast spectroscopy investigation. The charge transfer pathway in binary and ternary blends is revealed. And it is seen that ITIC leads to a faster exciton separation and exciton diffusion. ITIC in blends suppresses the geminate recombination and shows smaller amount of charge transfer states, which is beneficial for the device performance. And the addition of ITIC enhances the crystallinity for both donor and acceptor leads to a morphology change of forming bicontinuous crystalline networks and phase separation. In a consequence, fill factor and JSC, increase dramatically for the related OSC.

Effect of mixed diluents during thermally induced phase separation process on structures and performances of hollow fiber membranes prepared using triple-orifice spinneret

In this study, polyvinylidene fluoride hollow fiber membranes were prepared using a triple-orifice spinneret in thermally induced phase separation. A solvent, propylene carbonate (PC), was extruded through the outermost layer of the spinneret. Through the use of this method, all the membranes were developed an entirely porous surface with similar pore size and porosity. Using mixed diluents with different concentrations of diphenyl carbonate and PC, the membrane bulk structures were controlled from an entirely bicontinuous network, a combination of bicontinuous and spherulitic structures, to an entirely spherulitic structure. The tailored bulk structures showed significant effects on the permeability, rejection, and mechanical strength of the membrane. Furthermore, the membrane sub-layer structure was modified to form different types from the composite-like structure of the combination of the spherulites and bicontinuous network to entirely spherulites, which controlled the membrane permeation stability within an extensive range of 6% to nearly 100%. A change in the polymeric dope solution phase diagram, as well as the interfacial behaviors of the polymeric dope solution and extruded PC, played important roles in appropriately tailoring membrane structures and performances. These novel and solid findings regarding the connections between structures and performances provide an advisable venue for the design of hollow fiber membranes with satisfactory performances.

Fabrication of bicontinuous double networks as thermal and pH stimuli responsive drug carriers for on-demand release.

The fabrication, via a two steps approach, of a novel bicontinuous Double Network (BCDN) material is reported. We first use a bicontinuous emulsion as template to obtain a poly(butyl acrylate) (PBA) and poly(acrylic acid) (PAA) bicontinuous amphiphilic material. The material is then swollen with the precursor of a second hydrophilic polymer (PNIPAM, poly(N-isopropylacrylamide)). After polymerization of these precursors, the two responsive polymers, PNIPAM and PAA, form a double-network within a bicontinuous templated material, i.e. a bicontinuous double network (BCDN) material. The advantages of using such unique and complex double network architecture are manifold. PBA increases the mechanical properties of the hydrogel all together with the hydrophilic double network that also decouples the pH and temperature responsiveness. Among different possible applications, we tested this responsive hydrogels for its biomedical application. It can be used as pH and temperature sensitive devices for on-demand drug delivery. In addition, the release of a drug confined in the amphiphilic bicontinuous structure follows different kinetics profiles, depending on pH and temperature. This last result indicates that it is possible to control and regulate the release of an encapsulated drug according to the fluctuations of physiological conditions.

Ternary Organic Solar Cells with Efficiency >16.5% Based on Two Compatible Nonfullerene Acceptors.

A ternary structure has been demonstrated as being an effective strategy to realize high power conversion efficiency (PCE) in organic solar cells (OSCs); however, general materials selection rules still remain incompletely understood. In this work, two nonfullerene small-molecule acceptors 3TP3T-4F and 3TP3T-IC are synthesized and incorporated as a third component in PM6:Y6 binary blends. The photovoltaic behaviors in the resultant ternary OSCs differ significantly, despite the comparable energy levels. It is found that incorporation of 15% 3TP3T-4F into the PM6:Y6 blend results in facilitating exciton dissociation, increasing charge transport, and reducing trap-assisted recombination. All these features are responsible for the enlarged PCE of 16.7% (certified as 16.2%) in the PM6:Y6:3TP3T-4F ternary OSCs, higher than that (15.6%) in the 3TP3T-IC containing ternary devices. The performance differences are mainly ascribed to the compatibility between the third component and the host materials. The 3TP3T-4F guest acceptor exhibits an excellent compatibility with Y6, tending to form well-mixed phases in the ternary blend without disrupting the favored bicontinuous transport networks, whereas 3TP3T-IC displays a morphological incompatibility with Y6. This work highlights the importance of considering the compatibility for materials selection toward high-efficiency ternary organic OSCs.

High crystalline small molecule manipulates polymer-fullerene morphology and enables 20% improvement in fill factor and device performance

Abstract A morphology of bi-continuous donor-acceptor network absorber is critical to achieve high-performance organic solar cells and the rational control of the morphology is hard to realize. In this work, two high crystalline acceptor-donor-acceptor (A-D-A) conjugated small molecules (ITDCN, ITDCF) were synthesized and employed as the third component for PBDB-T/PC71BM system. Although ITDCN and ITDCF do not have favorable complementary absorption and cascade energy level alignment to PBDB-T and PC71BM, addition of ITDCN or ITDCF into PBDB-T:PC71BM binary system significantly improves device fill factor (up to 20%) and open circuit voltage (20–40 mV). Characterization using space-charge limited current (SCLC), AFM and TEM shows addition of ITDCN or ITDCF manipulates absorber film phase separation which leads to improved and balanced charge carrier mobility. A power conversion efficiency of 6.68% has been achieved in PBDB-T:ITDCN:PC71BM ternary solar cell with 15% ITDCN which is 24% higher than binary device. Our results suggest introducing high crystalline small molecule into polymer-fullerene system is an effective strategy to rationally control film morphology and improve polymer/fullerene solar cell performance.

Face-on orientation and vertical phase separation of p-DTS(FBTTh2)2/PC70BM induced by epitaxial crystallization of polymer interface layer

Abstract It is important to arrange the donor and acceptor phases and molecules within those phases in a way that optimizes relevant optoelectronic processes required for efficient operation of bulk-heterojunction (BHJ) organic solar cells (OSCs). 7,7′-(4,4-bis(2-ethylhexyl)-4H-silolo[3,2-b:4,5-b′]dithiophene-2,6-diyl)bis(6-fluoro-4(5′-hexyl-[2,2′-bithiophen]-5-yl)benzo[c][1,2,5]thiadiazole) (p-DTS(FBTTh2)2) tends to adopt edge-on orientation with respect to PEDOT/PSS substrate, which is adverse to charge and exciton transport in the vertical direction. Besides, [6,6]-phenyl-C71-butyric acid methyl ester (PC70BM) tends to deposit on PEDOT/PSS substrate, while p-DTS(FBTTh2)2 is inclined to accumulate at surface, which blocks charge transport and increases injection barrier of charge. Here, we tried to optimize both the molecular orientation and vertical phase separation of p-DTS(FBTTh2)2/PC70BM with proper crystal size and bicontinuous network structure. Poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene-co-3-fluorothieno[3,4-b]thiophene-2-carboxylate], (PTB7-Th) was used as the interfacial layer to induce p-DTS(FBTTh2)2 to adopt face-on orientation because of epitaxial crystallization. At the same time, vertical phase separation can be improved due to that p-DTS(FBTTh2)2 tends to deposit on PTB7-Th. Consequently, the efficiency of exciton separation of devices with PTB7-Th as the interfacial layer is improved and both the hole and electron mobility were increased and became more balanced. As a result, the power conversion efficiency (PCE) increased from 5.47% to 6.74%.

Controllable coacervation of recombinantly produced spider silk protein using kosmotropic salts

Recent developments suggest that the phase transition of natural and synthetic biomacromolecules represents an important and ubiquitous mechanism underlying structural assemblies toward the fabrication of high-performance materials. Such a transition results in the formation of condensed liquid droplets, described as condensates or coacervates. Being able to effectively control the assembly of such entities is essential for tuning the quality and their functionality. Here we describe how self-coacervation of genetically engineered spidroin-inspired proteins can be preceded by a wide range of kosmotropic salts. We studied the kinetics and mechanisms of coacervation in different conditions, from direct observation of initial phase separation to the early stage of nucleation/growth and fusion into large fluid assemblies. We found that coacervation induced by kosmotropic salts follows the classical nucleation theory and critically relies on precursor clusters of few weak-interacting protein monomers. Depending on solution conditions and the strength of the supramolecular interaction as a function of time, coacervates with a continuum of physiochemical properties were observed. We observed similar characteristics in other protein-based coacervates, which include having a spherical-ellipsoid shape in solution, an interconnected bicontinuous network, surface adhesion, and wetting properties. Finally, we demonstrated the use of salt-induced self-coacervates of spidroin-inspired protein as a cellulosic binder in dried condition.

Effect of oil contents on gluten network during the extrusion processing

To investigate a comparative evaluation of the gluten polymerization properties at different oil contents during the extrusion processing, the electrophoretic profiles of the gluten, free sulfhydryl (SH) compounds, the secondary structure of gluten, glutenin macropolymer contents and gluten network were measured. Five gluten samples were formulated by adding different oil contents. The low molecular weight contents of gluten decreased as well as the high molecular weight contents increased during the extrusion processing. The free SH of gluten at 8 or 10% oil content drops significantly to a minimum. The β-sheets contents of gluten have significantly difference between the treatments and control, except for 15 and 20% oil content treatments. Confocal laser scanning microscopy of mixed glutens correlated to the degree of oil contents with the gluten in the bi-continuous gluten network.

Periodic Bicontinuous Structures Formed on the Top Surface of Asymmetric Triblock Terpolymer Thick Films.

The combination of the nonsolvent-induced phase separation (NIPS) process with a solvent vapor annealing (SVA) treatment is used to produce asymmetric and hydrophobic thick films having different long-range ordered network nanostructures, which are inaccessible via currently available membrane fabrication methods. We show that the disordered phase generated by NIPS on the material top surface can be transformed into a highly ordered bicontinuous network nanostructure during the SVA process without disrupting the substructure morphology. For instance, by using a straightforward blending approach, either a triply periodic alternating diamond (DA) structure or a core-shell perforated lamellar (PL) phase was demonstrated on the skin layer of fully hydrophobic poly(1,1-dimethyl silacyclobutane)-block-polystyrene-block-poly(methyl methacrylate) (PDMSB-b-PS-b-PMMA) thick films. Such a material fabrication method, enabling the formation of a sponge-like substructure topped by a network phase having an excellent long-range order, provides an appealing strategy to facilitate the manufacture of next-generation membranes at large scale since these bicontinuous morphologies obviate the need of the nanochannel alignment.

Numerical Investigation of Polymer Coated Nanoporous Gold.

Nanoporous metals represent a fascinating class of materials. They consist of a bi-continuous three-dimensional network of randomly intersecting pores and ligaments where the ligaments form the skeleton of the structure. The open-pore structure allows for applying a thin electrolytic coating on the ligaments. In this paper, we will investigate the stiffening effect of a polymer coating numerically. Since the coating adds an additional difficulty for the discretization of the microstructure by finite elements, we apply the finite cell method. This allows for deriving a mesh in a fully automatic fashion from the high resolution 3D voxel model stemming from the 3D focused ion beam-scanning electron microscope tomography data of nanoporous gold. By manipulating the voxel model in a straightforward way, we add a thin polymer layer of homogeneous thickness numerically and study its effect on the macroscopic elastic properties systematically. In order to lower the influence of the boundary conditions on the results, the window method, which is known from homogenization procedures, is applied. In the second part of the paper, we fill the gap between numerical simulations and experimental investigations and determine real material properties of an electrolytic applied polypyrrole coating by inverse computations. The simulations provide an estimate for the mechanical properties of the ligaments and the polymeric coating and are in accordance with experimental data.

(Invited) Heteronanomat Frameworks As a New Electrode Design for Advanced Lithium-Ion Batteries

Forthcoming smart energy era is in strong pursuit of advanced power sources with reliable electrochemical performances. To date, most research approaches have still relied on traditional synthetic materials and stereotyped electrode architecture (i.e., thickness-directional, simple pile-up of electrode active materials/conductive additives/polymeric binders on top of metallic current collectors), which have posed major obstacles to sustainable progress of the energy storage systems. For example, the presence of electrochemically-inert materials such as metallic current collectors and polymer binders exerts negative influence on volumetric/gravimetric capacity of electrodes. Moreover, the monotonous electrode architecture often gives rise to electrode thickness-dependent irregularity of electronic/ionic conduction pathways and also loss of structural integrity upon external deformation stresses. Here, we demonstrate a new class of heteronanomat-structured electrodes based on carbon nanotubes (CNTs), cellulose nanofibrils and electrospun polymeric nanofibers to resolve the long-standing challenges of conventional electrodes described above. This material/structural uniqueness allows the formation of three-dimensional bicontinuous CNT electron networks and electrolyte conduction channels, in addition to improving the mass loading of electrode active materials and also mechanical flexibility. As a result, the heteronanomat electrodes provide unprecedented advances in the electrochemical performance and shape diversity that lie far beyond those achievable with conventional battery electrode architectures. We envision that the heteronanomat-structured electrode strategy holds a great deal of promise as a reliable and versatile platform technology to open a new route toward advanced lithium-ion batteries. References Sang-Young Lee et al. Adv. Energy Mater. 2017, 1701099.Sang-Young Lee et al. Adv. Funct. Mater. 2015, 25, 6029.Sang-Young Lee et al. Adv. Energy Mater. 2015, 5, 1501194. Figure 1

Bicontinuous Network Nanostructure with Tunable Thickness Formed on Asymmetric Triblock Terpolymer Thick Films

Asymmetric poly(1,1-dimethyl silacyclobutane)-block-polystyrene-block-poly(2-vinyl pyridine) (PDMSB-b-PS-b-P2VP) thick films, consisting of a spongelike substructure topped by a nanostructured dense top layer, were produced by combining a fast self-assembly of the triblock terpolymer chains with nonsolvent-induced phase separation (referred as SNIPS). A controlled evolution of the thickness and morphology of the nanostructured top layer was achieved upon solvent vapor annealing (SVA). For instance, the sub-100 nm thick square array morphology generated by SNIPS is transformed into a 1.5 mu m thick core-shell perforated lamellar (PL) structure when exposed to a chloroform (CHCl3) vapor for 3 h. A PL phase having highly ordered continuous P2VP nanochannels can be envisioned as an appealing morphology for membrane applications, since such a network structure formed on asymmetric PDMSB-b-PS-b-P2VP thick films obviates the need for alignment. Monoliths entirely composed of the bicontinuous PL structure were also produced by increasing the duration of the SVA treatment (18 h, CHCl3)

Optimal bulk-heterojunction morphology enabled by fibril network strategy for high-performance organic solar cells

A bicontinuous network formed spontaneously upon film preparation is highly desirable for bulk-heterojunction (BHJ) organic solar cells (OSCs). Many donor-acceptor (D-A) type conjugated polymers can self-assemble into polymer fibrils in the solid state and such fibril-assembly can construct the morphological framework by forming a network structure, inducing the formation of ideal BHJ morphology. Our recent works have revealed that the fibril network strategy (FNS) can control the blend morphology in fullerene, non-fullerene and ternary OSCs. It has been shown that the formation of fibril network can optimize phase separation scale and ensure efficient exciton dissociation and charge carriers transport, thus leading to impressive power conversion efficiencies (PCEs) and high fill factor (FF) values. We believe that FNS will provide a promising approach for the optimization of active layer morphology and the improvement of photovoltaic performance, and further promote the commercialization of OSCs.