Redox reactions on TCNQ-modified self-assembled monomolecular films

Suitably modified mono- and bimolecular films, including bilayer lipid membranes (BLMs), offer exceptionally good opportunities for probing electric field effects on charge transfer and redox reactions in biosensor and molecular electronics research and development. This work presents the redox reactions of tetracyano-p-quinodimethane (TCNQ) molecules incorporated in a self-assembled octadecanethiol monolayer (SAM) on polycrystalline gold electrodes, depending upon the type of supporting electrolyte cations and their concentration. Our results show that TCNQ-modified Au–SAM electrodes exhibit selectivity versus alkali metal cations in aqueous supporting electrolyte (∽10 kJ mol⁻¹ difference between K⁺ and Li⁺ and between Cs⁺ and K⁺). The slope of the ‘calibration curves’ for Li⁺ and K⁺ is about 59 mV per decade of concentration of the analyte. The explanation of this behaviour is based on the Donnan potential model; however, an ion-pairing effect can also be involved. Our preliminary results show also that the TCNQ molecules within the octadecanethiol monolayer may act as a molecular redox device. © 1998 John Wiley & Sons, Ltd.     

Supramolecular‐Assembled Nanoporous Film with Switchable Metal Salts for a Triboelectric Nanogenerator

A triboelectric nanogenerators (TENG) are of great interest as emerging power harvesters because of their simple device architecture with unprecedented high efficiency. Despite the substantial development of new constituent materials and device architectures, a TENG with a switchable surface on a single device, which allows for facile control of the triboelectric output performance, remains a challenge. Here, a supramolecular route for fabricating a novel TENG based on an alkali‐metal‐bound porous film, where the alkali metal ions are readily switched among one another is demonstrated. The soft nanoporous TENG contains numerous SO₃^? groups on the surface of nanopores prepared from the supramolecular assembly of sulfonic‐acid‐terminated polystyrene and poly(2‐vinylpyridine) (P2VP), followed by soft etching of P2VP. Selective binding of alkali metal ions, including Li⁺, Na⁺, K⁺, and Cs⁺, with SO₃^? groups enables the development of mechanically robust alkali‐metal‐ion‐decorated TENGs. The triboelectric output performance of the devices strongly depends on the alkali metal ion species, and the output power ranges from 11.5 to 256.5 µW. This wide‐range triboelectric tuning can be achieved simply by a conventional ion exchange process in a reversible manner, thereby allowing reversible control of the output performance in a single device platform.     

Fluorescence‐Amplifying Detection of Hydrogen Peroxide with Cationic Conjugated Polymers,and Its Application to Glucose Sensing

A highly sensitive hydrogen peroxide probe that takes advantage of the amplified fluorescence quenching of conjugated polymers has been developed. The cationic conjugated polymer, poly(9,9‐bis(6′‐N,N,N‐trimethylammonium‐hexyl) fluorene phenylene) (PFP‐NMe₃⁺) and peroxyfluor‐1 with boronate protecting groups (Fl‐BB) are used to detect H₂O₂ optically. Without the addition of H₂O₂, the absence of electrostatic interactions between the cationic PFP‐NMe₃⁺ and the neutral Fl‐BB keeps the Fl‐BB well separated from the PFP‐NMe₃⁺, and no fluorescence quenching of the PFP‐NMe₃⁺ occurs. In the presence of H₂O₂, the formation of the anionic quencher, fluorescein, by specific reaction of the Fl‐BB with H₂O₂ results in strong electrostatic interactions between the PFP‐NMe₃⁺ and the fluorescein, and therefore efficient fluorescence quenching of the PFP‐NMe₃⁺ occurs. The absorption of fluorescein overlaps the emission of PFP‐NMe₃⁺, which encourages fluorescence resonance energy transfer (FRET) from the PFP‐NMe₃⁺ to the fluorescein. The H₂O₂ probe has very good sensitivity, with a detection range of 15 to 600 nM. Since glucose oxidase (GOx) can specifically catalyze the oxidation of β‐D ‐(+)‐glucose to generate H₂O₂, glucose detection is also realized with the H₂O₂ probe as the signal transducer.     

Band Diagram and Rate Analysis of Thin Film Spinel LiMn2O4 Formed by Electrochemical Conversion of ALD‐Grown MnO

Nanoscale spinel lithium manganese oxide is of interest as a high‐rate cathode material for advanced battery technologies among other electrochemical applications. In this work, the synthesis of ultrathin films of spinel lithium manganese oxide (LiMn₂O₄) between 20 and 200 nm in thickness by room‐temperature electrochemical conversion of MnO grown by atomic layer deposition (ALD) is demonstrated. The charge storage properties of LiMn₂O₄ thin films in electrolytes containing Li⁺, Na⁺, K⁺, and Mg²⁺ are investigated. A unified electrochemical band‐diagram (UEB) analysis of LiMn₂O₄ informed by screened hybrid density functional theory calculations is also employed to expand on existing understanding of the underpinnings of charge storage and stability in LiMn₂O₄. It is shown that the incorporation of Li⁺ or other cations into the host manganese dioxide spinel structure (λ‐MnO₂) stabilizes electronic states from the conduction band which align with the known redox potentials of LiMn₂O₄. Furthermore, the cyclic voltammetry experiments demonstrate that up to 30% of the capacity of LiMn₂O₄ arises from bulk electronic charge‐switching which does not require compensating cation mass transport. The hybrid ALD‐electrochemical synthesis, UEB analysis, and unique charge storage mechanism described here provide a fundamental framework to guide the development of future nanoscale electrode materials for ion‐incorporation charge storage.     

Solution‐Processed,Alkali Metal‐Salt‐Doped,Electron‐Transport Layers for High‐Performance Phosphorescent Organic Light‐Emitting Diodes

High‐performance, blue, phosphorescent organic light‐emitting diodes (PhOLEDs) are achieved by orthogonal solution‐processing of small‐molecule electron‐transport material doped with an alkali metal salt, including cesium carbonate (Cs₂CO₃) or lithium carbonate (Li₂CO₃). Blue PhOLEDs with solution‐processed 4,7‐diphenyl‐1,10‐phenanthroline (BPhen) electron‐transport layer (ETL) doped with Cs₂CO₃ show a luminous efficiency (LE) of 35.1 cd A^?1 with an external quantum efficiency (EQE) of 17.9%, which are two‐fold higher efficiency than a BPhen ETL without a dopant. These solution‐processed blue PhOLEDs are much superior compared to devices with vacuum‐deposited BPhen ETL/alkali metal salt cathode interfacial layer. Blue PhOLEDs with solution‐processed 1,3,5‐tris(m‐pyrid‐3‐yl‐phenyl)benzene (TmPyPB) ETL doped with Cs₂CO₃ have a luminous efficiency of 37.7 cd A^?1 with an EQE of 19.0%, which is the best performance observed to date in all‐solution‐processed blue PhOLEDs. The results show that a small‐molecule ETL doped with alkali metal salt can be realized by solution‐processing to enhance overall device performance. The solution‐processed metal salt‐doped ETLs exhibit a unique rough surface morphology that facilitates enhanced charge‐injection and transport in the devices. These results demonstrate that orthogonal solution‐processing of metal salt‐doped electron‐transport materials is a promising strategy for applications in various solution‐processed multilayered organic electronic devices.     

Barium Hydroxide as an Interlayer Between Zinc Oxide and a Luminescent Conjugated Polymer for Light‐Emitting Diodes

A study of hybrid light‐emitting diodes (HyLEDs) fabricated with and without solution‐processible Cs₂CO₃ and Ba(OH)₂ inorganic interlayers is presented. The interlayers are deposited between a zinc oxide electron‐injection layer and a fluorescent emissive polymer poly(9‐dioctyl fluorine–alt‐benzothiadiazole) (F8BT) layer, with a thermally evaporated MoO₃/Au layer used as top anode contact. In comparison to Cs₂CO₃, the Ba(OH)₂ interlayer shows improved charge carrier balance in bipolar devices and reduced exciton quenching in photoluminance studies at the ZnO/Ba(OH)₂/F8BT interface compared to the Cs₂CO₃ interlayer. A luminance efficiency of ≈28 cd A^?1 (external quantum efficiency (EQE) ≈ 9%) is achieved for ≈1.2 μm thick single F8BT layer based HyLEDs. Enhanced out‐coupling with the aid of a hemispherical lens allows further efficiency improvement by a factor of 1.7, increasing the luminance efficiency to ≈47cd A^?1, corresponding to an EQE of 15%. The photovoltaic response of these structures is also studied to gain an insight into the effects of interfacial properties on the photoinduced charge generation and back‐recombination, which reveal that Ba(OH)₂ acts as better hole blocking layer than the Cs₂CO₃ interlayer.     

Membrane‐Free Detection of Metal Cations with an Organic Electrochemical Transistor

Alkali‐metal ions, particularly sodium (Na⁺) and potassium (K⁺), are the messengers of living cells, governing a cascade of physiological processes through the action of ion channels. Devices that can monitor, in real time, the concentrations of these cations in aqueous media are in demand not only for the study of cellular machinery, but also to detect conditions in the human body that lead to electrolyte imbalance. In this work, conducting polymers are developed that respond rapidly and selectively to varying concentrations of Na⁺ and K⁺ in aqueous media. These polymer films, bearing crown‐ether‐functionalized thiophene units specific to either Na⁺ or K⁺, generate an electrical output proportional to the cation type and concentration. Using electropolymerization, the ion‐selective polymers are integrated as the gate electrode of an organic electrochemical transistor (OECT). The OECT current changes with respect to the concentration of the ion to which the polymer electrode is selective. Designed as a single, miniaturized chip, the OECT enables the selective detection of the cations within a physiologically relevant range. These electrochemical ion sensors require neither ion‐selective membranes nor a reference electrode to operate and have the potential to surpass existing technologies for the detection of alkali‐metal ions in aqueous media.     

π‐Conjugation Enables Ultra‐High Rate Capabilities and Cycling Stabilities in Phenothiazine Copolymers as Cathode‐Active Battery Materials

In recent years, organic battery cathode materials have emerged as an attractive alternative to metal oxide–based cathodes. Organic redox polymers that can be reversibly oxidized are particularly promising. A drawback, however, often is their limited cycling stability and rate performance in a high voltage range of more than 3.4 V versus Li/Li⁺. Herein, a conjugated copolymer design with phenothiazine as a redox‐active group and a bithiophene co‐monomer is presented, enabling ultra‐high rate capability and cycling stability. After 30 000 cycles at a 100C rate, >97% of the initial capacity is retained. The composite electrodes feature defined discharge potentials at 3.6 V versus Li/Li⁺ due to the presence of separated phenothiazine redox centers. The semiconducting nature of the polymer allows for fast charge transport in the composite electrode at a high mass loading of 60 wt%. A comparison with three structurally related polymers demonstrates that changing the size, amount, or nature of the side groups leads to a reduced cell performance. This conjugated copolymer design can be used in the development of advanced redox polymers for batteries.     

Enhanced Incorporation of Guanidinium in Formamidinium‐Based Perovskites for Efficient and Stable Photovoltaics: The Role of Cs and Br

Recently, incorporating guanidium (GA) cations into organolead halide perovskites is shown to effectively improve the stability and performance of the solar cells. However, the underlying mechanisms that govern the GA incorporation have remained unclear. Here, FAPbI₃ is used as a basic framework to investigate experimentally and theoretically the role of cesium (Cs) and bromine (Br) substitutions in GA⁺ incorporation. It is found that simultaneous introduction of the small‐size Cs⁺ and Br^– in the FAPbI₃ lattice is critical to create sufficient space for the large GA⁺ and that the presence of the Cs⁺ prevents the formation of a GA‐contained low‐dimensional phase, which both assist GA⁺ incorporation. Upon entering the perovskite lattice, the GA⁺ can stabilize the lattice structure via forming strong hydrogen bonds with their neighboring halide ions. Such structure modification suppresses halide vacancy formation, thus leading to improved material properties. Compared to the GA‐free perovskite reference samples, the optimal system GA_0.05Cs_0.15FA_0.8Pb(I_0.85Br_0.15)₃ exhibits substantially improved thermal and photothermal stability, as well as increased photocarrier lifetime. Solar cells fabricated with the optimal material system show an excellent photovoltaic performance, with the champion device reaching a power conversion efficiency of 21.3% and an open circuit voltage of 1.229 V.     

Positively K+‐Responsive Membranes with Functional Gates Driven by Host–Guest Molecular Recognition

A novel positively K⁺‐responsive membrane with functional gates driven by host‐guest molecular recognition is prepared by grafting poly(N‐isopropylacrylamide‐co‐acryloylamidobenzo‐15‐crown‐5) (poly(NIPAM‐co‐AAB₁₅C₅)) copolymer chains in the pores of porous nylon‐6 membranes with a two‐step method combining plasma‐induced pore‐filling grafting polymerization and chemical modification. Due to the cooperative interaction of host‐guest complexation and phase transition of the poly(NIPAM‐co‐AAB₁₅C₅), the grafted gates in the membrane pores could spontaneously switch from “closed” state to “open” state by recognizing K⁺ ions in the environment and vice versa; while other ions (e.g., Na⁺, Ca²⁺ or Mg²⁺) can not trigger such an ion‐responsive switching function. The positively K⁺‐responsive gating action of the membrane is rapid, reversible, and reproducible. The proposed K⁺‐responsive gating membrane provide a new mode of behavior for ion‐recognizable “smart” or “intelligent” membrane actuators, which is highly attractive for controlled release, chemical/biomedical separations, tissue engineering, sensors, etc.     

Synthesis,Electrochemical and Photophysical Properties,and Electroluminescent Performance of the Octa‐ and Deca(aryl)[60]fullerene Derivatives

Three multifunctionalized organo[60]fullerene derivatives, C₆₀Ph₅(C₆H₄‐^tBu‐4)₅Me₂ (cyclophenacene, 1 ), C₆₀Ph₅(C₆H₄‐^tBu‐4)₅Me₂ (fused corannulene, 2 ), and C₆₀Ph₅(C₆H₄‐^tBu‐4)₃Me₂ (phenylene‐bridged fused corannulene, 3 ) are synthesized by the reaction of C₆₀Ph₅Me with 4‐tert‐butylphenylcopper reagent in the presence of pyridine, followed by treatment with MeI. Compounds 1 – 3 undergo reduction in the range from ?1.8 to ?2.5 V versus Fc/Fc⁺ and exhibit photoluminescence behavior with fluorescent quantum yields of 18.5%, 2.5%, and 3.2% with fluorescent lifetimes of 67, 1.1, and 27 ns ( 1 – 3 , respectively). Organic electroluminescent diode devices using 1 – 3 are fabricated with π‐conjugated polymers and show external electroluminescent efficiencies of 0.04%, 0.07%, and 0.03% emitting yellow, green, and red light, respectively. The device containing all three compounds emits white light. This result indicates that the bulky addends in 1 – 3 can effectively isolate the π‐conjugated systems of the molecules in the solid state and retard the intermolecular excited‐state quenching process.     

A Rechargeable Battery with an Iron Metal Anode

To date, tremendous efforts of the battery community are devoted to batteries that employ Li⁺, Na⁺, and K⁺ as charge carriers and nonaqueous electrolytes. However, aqueous batteries hold great promise for stationary energy storage due to their inherent low cost and high safety. Among metal batteries that use aqueous electrolytes, zinc metal batteries are the focus of attention. In this study, iron as an anode candidate in aqueous batteries is investigated because iron is undoubtedly the most earth‐abundant and cost‐effective metal anode. Reversible iron plating/stripping in a FeSO₄ electrolyte is demonstrated on the anode side and reversible topotactic (de)insertion of Fe²⁺ in a Prussian blue analogue cathode is showcased. Furthermore, it is revealed that LiFePO₄ can pair up with the iron metal anode in a hybrid cell, delivering stable performance as well.     

Fast Potassium Storage in Hierarchical Ca0.5Ti2(PO4)3@C Microspheres Enabling High‐Performance Potassium‐Ion Capacitors

Hybrid potassium‐ion capacitors (KICs) show great promise for large‐scale storage on the power grid because of cost advantages, the weaker Lewis acidity of K⁺ and low redox potential of K⁺/K. However, a huge challenge remains for designing high‐performance K⁺ storage materials since K⁺ ions are heavier and larger than Li⁺ and Na⁺. Herein, the synthesis of hierarchical Ca_0.5Ti₂(PO₄)₃@C microspheres by use of the electrospraying method is reported. Benefiting from the rich vacancies in the crystal structure and rational nanostructural design, the hybrid Ca_0.5Ti₂(PO₄)₃@C electrode delivers a high reversible capacity (239 mA h g^?1) and superior rate performance (63 mA h g^?1 at 5 A g^?1). Moreover, the KIC employing a Ca_0.5Ti₂(PO₄)₃@C anode and activated carbon cathode, affords a high energy/power density (80 W h kg^?1 and 5144 W kg^?1) in a potential window of 1.0–4.0 V, as well as a long lifespan of over 4000 cycles. In addition, in situ X‐ray diffraction is used to unravel the structural transition in Ca_0.5Ti₂(PO₄)₃, suggesting a two‐phase transition above 0.5 V during the initial discharge and solid solution processes during the subsequent K⁺ insertion/extraction. The present study demonstrates a low‐cost potassium‐based energy storage device with high energy/power densities and a long lifespan.     

Stabilizing Polymer–Lithium Interface in a Rechargeable Solid Battery

Solid polymer electrolytes (SPEs) are promising candidates for developing high‐energy‐density Li metal batteries due to their flexible processability. However, the low mechanical strength as well as the inferior interfacial regulation of ions between SPEs and Li metal anode limit the suppress ion of Li dendrites and destabilize the Li anode. To meet these challenges, interfacial engineering aiming to homogenize the distribution of Li⁺/electron accompanied with enhanced mechanical strength by Mg₃N₂ layer decorating polyethylene oxide is demonstrated. The intermediary Mg₃N₂ in situ transforms to a mixed ion/electron conducting interlayer consisting of a fast ionic conductor Li₃N and a benign electronic conductor Mg metal, which can buffer the Li⁺ concentration gradient and level the nonuniform electric current distribution during cycling, as demonstrated by a COMSOL Multiphysics simulation. These characteristics endow the solid full cell with a dendrite‐free Li anode and enhanced cycling stability and kinetics. The innovative interface design will accelerate the commercial application of high‐energy‐density solid batteries.     

Amorphization Boost Multi-Ions Storage for High-Performance Aqueous Batteries

Regarding the complex properties of various cations, the design of aqueous batteries that can simultaneously store multi-ions with high capacity and satisfactory rate performance is a great challenge. Here an amorphization strategy to boost cation-ion storage capacities of anode materials is reported. In monovalent (H⁺, Li⁺, K⁺), divalent (Mg²⁺, Ca²⁺, Zn²⁺) and even trivalent (Al³⁺) aqueous electrolytes, the capacity of the resulting amorphous MoO_x is more than quadruple than that of crystalline MoO_x and exceeds those of other reported multiple-ion storage materials. Both experimental and theoretical calculations reveal the generation of ample active sites and isotropic ions in the amorphous phase, which accelerates cation migration within the electrode bulk. Amorphous MoO_x can be coupled with multi-ion storage cathodes to realize electrochemical energy storage devices with different carriers, promising high energy and power densities. The power density exceeded 15000 W kg⁻¹, demonstrating the great potential of amorphous MoO_x in advanced aqueous batteries.     

Suppressing Ion Migration Enables Stable Perovskite Light‐Emitting Diodes with All‐Inorganic Strategy

Stability issue is one of the major concerns that limit emergent perovskite light‐emitting diodes (PeLEDs) techniques. Generally, ion migration is considered as the most important origin of PeLEDs degradation. In this work, an all‐inorganic device architecture, LiF/perovskite/LiF/ZnS/ZnSe, is proposed to address this imperative problem. The inorganic (Cs_1?xRb_x)_1?yK_yPbBr₃ perovskite is optimized with achieving a photoluminescence quantum yield of 67%. Depth profile analysis of X‐ray photoelectron spectroscopy indicates that the LiF/perovskite/LiF structure and the ZnS/ZnSe cascade electron transport layers significantly suppress the electric‐field‐induced ion migrations of the perovskite layers, and impede the diffusion of metallic atoms from cathode into perovskites. The as‐prepared PeLEDs display excellent shelf stability (maintaining 90% of the initial external quantum efficiency [EQE] after 264 h) and operational stability (half‐lifetime of about 255 h at an initial luminance of 120 cd m^?2). The devices also exhibit a maximum brightness of 15 6155 cd m^?2 and an EQE of 11.05%.     

Reduced Surfactant Uptake in Three Dimensional Assemblies of VOx Nanotubes Improves Reversible Li+ Intercalation and Charge Capacity

The relationship between the nanoscale structure of vanadium pentoxide nanotubes and their ability to accommodate Li⁺ during intercalation/deintercalation is explored. The nanotubes are synthesized using two different precursors through a surfactant‐assisted templating method, resulting in standalone VO _x (vanadium oxide) nanotubes and also “nano‐urchin”. Under highly reducing conditions, where the interlaminar uptake of primary alkylamines is maximized, standalone nanotubes exhibit near‐perfect scrolled layers and long‐range structural order even at the molecular level. Under less reducing conditions, the degree of amine uptake is reduced due to a lower density of V⁴⁺ sites and less V₂O₅ is functionalized with adsorbed alkylammonium cations. This is typical of the nano‐urchin structure. High‐resolution TEM studies revealed the unique observation of nanometer‐scale nanocrystals of pristine unreacted V₂O₅ throughout the length of the nanotubes in the nano‐urchin. Electrochemical intercalation studies revealed that the very well ordered xerogel‐based nanotubes exhibit similar specific capacities (235 mA h g^?1) to Na⁺‐exchange nanorolls of VO_x (200 mA h g^?1). By comparison, the theoretical maximum value is reported to be 240 mA h g^?1. The VOTPP‐based nanotubes of the nano‐urchin 3D assemblies, however, exhibit useful charge capacities exceeding 437 mA h g^?1, which is a considerable advance for VO_x based nanomaterials and one of the highest known capacities for Li⁺ intercalated laminar vanadates.     

Superhydrophilic All-pH-Adaptable Redox Conjugated Porous Polymers as Universal and Ultrarobust Ion Hosts for Diverse Energy Storage with Chemical Self-Chargeability

Herein, a new fibrous conjugated microporous polymer bearing phenazine species (PNZ-CMP) is reported as a universal and ultrastable electrode to host various mono- and multi-valent charge carriers for diverse aqueous rechargeable cells combining rapid kinetics, ultralong lifespan, and chemical rechargeability. The porous cross-linked structure, interconnected donor-acceptor network, and readily accessible active sites endow PNZ-CMP with highly-reversible redox activity, superhydrophilicity, facile electron transport, high ion diffusion coefficient, and all-pH-adaptability (−1 to 15) in aqueous electrolytes. Thus, adopting PNZ-CMP electrodes enables good compatibility with H⁺/Li⁺/Na⁺/K⁺/Zn²⁺/Al³⁺ ions and fast surface-controlled redox reactions for diverse aqueous battery chemistry. Multiple PNZ-CMP-based full cells show superior electrochemical performance especially ultralong lifespan, e.g., ≈84% capacity retention over 200 days for K⁺, ≈100% over 127 days for Zn²⁺, and ≈76% over 47 days for anion-coordinated Al ions, surpassing small molecule counterparts and most previously-reported corresponding systems. The spontaneous redox chemistry of reduced phenazine species with O₂ is first explored to render PNZ-CMP with repeatable chemical self-chargeability in four electrolytes. Especially in 0.05 m H₂SO₄, an accumulative discharge capacity up to 48505 mAh g⁻¹ is achieved via facile self-charging, which can originate from the “reactive antiaromaticity to stable aromaticity” conversion of the redox moieties as revealed by theoretical studies.     

pH, pK and pNa detection properties of SiO2/Si3N4 ISFET chemical sensors

This article reports the technological fabrication and the electrical characterisation of SiO₂/Si₃N₄ ion sensitive field effect transistors (ISFET) for the detection of H⁺, K⁺ and Na⁺ ions. ISFET chemical sensors show quasi-nernstian pH response with sensitivities around 54 mV/pH. pK and pNa measurements are also investigated, evidencing sensitivities lower than 20 mV/pH and non-nernstian pH-dependent phenomena for the highest K⁺ or Na⁺ concentrations (pK and pNa, respectively, lower than 4 and 3). It is shown that the detection properties of H⁺, K⁺ and Na⁺ ions are dependent on each other, being responsible for saturation effects for the highest concentrations. It is finally concluded that SiO₂/Si₃N₄ ISFETs are well adapted for the pH measurement, can be used for the pK or pNa measurements in the case of buffered solutions but are not fully suitable for multi-ion detection in the case of medical analysis.     

Nanodot‐Enhanced High‐Efficiency Pure‐White Organic Light‐Emitting Diodes with Mixed‐Host Structures

A relatively high‐efficiency, fluorescent pure‐white organic light‐emitting diode was fabricated using a polysilicic acid (PSA) nanodot‐embedded polymeric hole‐transporting layer (HTL). The diode employed a mixed host in the single emissive layer, which comprised 0.5 wt % yellow 5,6,11,12‐tetra‐phenylnaphthacene doped in the mixed host of 50 % 2‐(N,N‐diphenyl‐amino)‐6‐[4‐(N,N‐diphenylamino)styryl]naphthalene and 50 % N,N′‐bis‐(1‐naphthyl)‐N,N′‐diphenyl‐1,10‐biphenyl‐4‐4′‐diamine. By incorporating 7 wt % 3 nm PSA nanodot into the HTL of poly(3,4‐ethylene‐dioxythiophene)‐poly‐(styrenesulfonate), the efficiency at 100 cd m^–2 was increased from 13.5 lm W^–1 (14.7 cd A^–1; EQE: 7.2 %) to 17.1 lm W^–1 (17.6 cd A^–1; EQE: 8.3 %). The marked efficiency improvement may be attributed to the introduction of the PSA nanodot, leading to a better carrier‐injection‐balance.