Feng Li

Anhui University · Institutes of Physical Science and Information Technology

Unipolar barrier architecture is designed to enhance the photodetector's sensitivity by inducing highly asymmetrical barriers, a higher barrier for blocking majority carriers to depressing dark current, and a low minority carrier barrier without impeding the photocurrent flow through the channel. Depressed dark current without block photocurrent is...

A synergistic realization of high electrocaloric effect (ECE) and excellent temperature stability in ferroelectrics are foundation for practical applications, which is, however, a major challenge in ferroelectric cooling community thus far. In confront with this long‐standing issue, an emergent monomorphic ferrodistortion strategy in NaNbO3‐based r...

Antiferroelectric–ferroelectric phase transition in antiferroelectric (AFE) materials usually triggers high-performance electrocaloric effect (ECE), as represented by PbZrO3-based AFE. As an isostructure to PbZrO3, EC research in PbHfO3-based AFE ceramics are significantly left out. In this work, temperature dependent electrocaloric performances in...

Ceramic capacitors, known for their exceptional energy‐storage performance (ESP), are crucial components in high‐pulsed power systems. However, their ESP is significantly constrained by breakdown strength (Eb), which is influenced by interfacial polarization. This study delves into the physics, characterization, and application of interfacial polar...

Solid-state cooling, represented by the electrocaloric effect (ECE) in (anti)ferroelectric materials, has emerged as an alternative green refrigeration technology by virtue of its high efficiency and miniaturization and is expected to substitute conventional vapor-compression. Significant progress has been made in developing high-performance EC mat...

High‐sensitive uncooled mid‐wave infrared (MWIR) photodetection with fast speed is highly desired for biomedical imaging, optical communication, and night vision technology. Low‐dimensional materials with low dark current and broadband photoresponse hold great promise for use in MWIR detection. Here, this study reports a high‐performance MWIR photo...

Narrow bandgap 2D layered material platinum selenide (PtSe2) with good environmental stability, high carrier mobility, and high light absorption, has been widely investigated for uncooled midwave‐infrared (MWIR) photodetection. However, the phototransistor based on the PtSe2 operation at room temperature suffered from the high dark current and back...

Polarization‐sensitive infrared (IR) photodetection plays an important role in fiber optic communication, environmental monitoring, and remote sensing imaging. Semiconductors with quasi‐1D crystal structures exhibit unique optical and electrical properties due to their 1D carrier transport channels and large surface area‐to‐volume ratio, offering t...

Temperature stability of electrocaloric effect (ECE) is a thorny problem in ferroelectrics (FE). A general method is to design ferroelectric‐to‐relaxor phase transition at a sacrifice of electrocaloric (EC) strength. The Pb(Yb1/2Nb1/2)O3 antiferroelectrics (AFE) + Pb(Mg1/3Nb2/3)O3 relaxors strategy designed in this work is effective to tackle this...

Layered narrow bandgap quasi-two-dimensional (2D) transition metal dichalcogenides (TMDs) demonstrated excellent performance in long-wave infrared (LWIR) detection. However, the low light on/off ratio and specific detectivity (D*) due to the high dark current of the device fabricated using a single narrow bandgap material hindered its wide applicat...

The type‐II band‐aligned van der Waals (vdW) heterostructures are favorable for photocarrier separation and are often used for designing high‐performance photodetectors. Inspired by this, a metal‐mirror electrode enhanced HfSe 2 ‐InSe vdW heterostructure photodetector is designed and demonstrated excitement performance in UV light detection. It is...

Ultrahigh energy-storage performance of dielectric ceramic capacitors is generally achieved under high electric fields (HEFs). However, the HEFs strongly limit the miniaturization, integration, and lifetime of the dielectric energy-storage capacitors. Thus, it is necessary to develop new energy-storage materials with excellent energy-storage densit...

Order degree modulated ferroic response and electrocaloric effect (ECE) in Pb(B1, B2)O3–type B–site complex antiferroelectrics (AFEs) are explored in this work. Results show that local/phase structure and dielectric/ferroic properties are strikingly dependent on order degree (high, intermediate and low order degree for S1, S2 and S3 sample, respect...

Ambient temperature long‐wavelength infrared (LWIR) photodetection has many critical applications ranging from thermal imaging and optical communications to night vision cameras. Currently, high performance, low cost, air stability, and ultra‐broadband response still constitute challenges. Here, the study demonstrates a high‐performance uncooled LW...

To investigate the effect of A‐site substitution on phase‐structure evolution and electrocaloric effect (ECE) in filled tungsten bronze ceramics, Sr2–3x/2LaxNaNb4.3Ta0.7O15 (x = 0, 0.02, 0.04, and 0.06) ceramics are prepared through a two‐step solid‐state reaction method. Rietveld refinement shows that La2O3 addition achieves a partial transition f...

Broadband photodetectors based on 2D layered materials provide great potential applications in night vision, sensing, and communications. However, it remains a challenge for detectors to achieve both high photoresponsivity and fast response. Here, a high‐sensitive photodetector based on ReS 2 /BP van der Waals (vdW) heterodiode with fast speed, ris...

Oxygen vacancies (V O s) and their distribution can affect oxides' properties from various aspects. In this work, we present a dislocation-related surface-layer effect in single crystal SrTiO 3 (STO). Our results from the first principles calculations based on density functional theory along with our experimental research based on angle-resolved x-...

Dielectric capacitors with high power densities are crucial for pulsed electronic devices and clean energy technologies. However, their breakdown strengths (Eb) strongly limit their power densities. Herein, by modifying the interfacial polarization by adjusting the difference in activation energies (Δϕ) between the grain and grain boundary phases,...

Broad-bandgap semiconductor-based solar-blind ultraviolet (SBUV) photodetectors have attracted considerable research interest because of their broad applications in missile plume tracking, flame detectors, environmental monitoring, and optical communications due to their solar-blind nature and high sensitivity with low background radiation. Owing t...

BiFeO3–based ceramics possess an advantage over large spontaneous polarization and high Curie temperature, and are thus widely explored in the field of high–temperature lead–free piezoelectrics and actuators. However, poor piezoelectricity/resistivity and thermal stability of electrostrain make them less competitive. To address this problem, (1 − x...

Phase transition is expected in designing high-performance electrocaloric effect (ECE). However, hidden antiferroelectricity in NaNbO 3 -based ceramics complicates ECE evolution as compared to conventional ferroic materials. Therefore, a NaNbO 3 − xBi 0.5 Li 0.5 TiO 3 ( x = 0.08, 0.10, and 0.12) system is introduced to explore ECE performance in P...

Currently, lead-free ferroelectrics have been paid much attention due to their versatile applications, environmental friendliness and excellent energy storage properties (ESP). In this work, lead-free relaxor ferroelectrics (0.74-x)Na 0.5 Bi 0.5 TiO 3-0.06BaTiO 3-0.2SrTiO 3-xBi(Mg 0.5 Zr 0.5)O 3 with superior ESP were successfully designed via comp...

Dielectric energy storage devices are important components of high-power and pulsed electronic systems. High recoverable energy density (Wrec) and high efficiency (ƞ) are critical parameters for such applications. In this work we propose a strategy of polyphase engineering in the superparaelectric (SPE) state to achieve high-performance energy stor...

High-precision piezo actuators necessitate dielectrics with high electrostrain performance with low hysteresis. Polarity-modulated (Sr0.7Bi0.2□0.1)TiO3-based ceramics exhibit extraordinarily discrete multiphase coexistence regions: (i) the relaxor phase coexistence (RPC) region with local weakly polar tetragonal (T) and pseudocubic (Pc) short-range...

Lead-free relaxor ferroelectric ceramics with ultrahigh energy-storage performance are vital for pulsed power systems. We herein propose a strategy of phase and band structure engineering for high-performance energy storage. To demonstrate the effectiveness of this strategy, (1 - x)(0.75Na0.5Bi0.5TiO3-0.25SrTiO3)-xCaTi0.875Nb0.1O3 (NBT-ST-xCTN, x =...

In this work, (1 − x)(0.92NaNbO3–0.08BaTiO3)–xCa0.7La0.2TiO3 (NNBT – xCLT) ceramics were successfully designed and prepared by the solid-state reaction method. Investigations on the structure, dielectric, and energy storage properties were performed. The NNBT – 0.25CLT ceramic with orthorhombic phase at room temperature was found to exhibit extreme...

BaTiO3-based lead-free ceramics are mainstays of electrical functional materials in industry with mature technology and relatively low cost. However, the huge challenge of low recoverable energy storage density (Wrec) has long restricted their development in solid-state energy storage capacitors. Here, an ultrahigh Wrec of ∼9.04 J cm⁻³ and a large...

Room‐temperature‐operating highly sensitive mid‐wave infrared (MWIR) photodetectors are utilized in a large number of important applications including night vision, communications, and optical radar. Many previous studies have demonstrated uncooled MWIR photodetectors using two‐dimentional narrow‐bandgap semiconductors. To date, most of these works...

Owing to the high power density, excellent operational stability and fast charge/discharge rate, and environmental friendliness, the lead-free Na0.5Bi0.5TiO3 (NBT)-based relaxor ferroelectrics exhibit great potential in pulsed power capacitors. Herein, novel lead-free (1−x)(0.7Na0.5Bi0.5TiO3-0.3Sr0.7Bi0.2TiO3)-xBi(Mg0.5Zr0.5)O3 (NBT-SBT-xBMZ) relax...

Piezo–photocatalysis induced by ultrasound vibration and light irradiation is an emerging strategy to decelerate the rapid recombination of photoinduced charges in the catalytic process. Element doping-induced structural phase transition is an effective approach to improve catalytic performance. Herein, barium (Ba) doped sodium niobate (abbreviated...

High-performance dielectric materials are widely used in energy storage applications, and temperature stability at extreme conditions is rarely considered yet. In this work, the Bi 0.5 Na 0.5 TiO 3 –Sr 0.7 Bi 0.2□0.1 TiO 3 – xNaNbO 3 ( x = 0, 0.05, and 0.15) system is designed with a room-temperature ergodic relaxor character to explore energy stor...

In this work, (1-x)Pb0.7Ba0.3ZrO3–xBi(Mg0.5Ti0.5)O3 (PBZ–xBMT) compositions was designed with an integration of ferroelectric–relaxor transition and multiphase coexistence to synergistically optimize electrocaloric effect (ECE) and temperature stability. Rietveld refinements reveal a phase structure change with sequence of R3cH → R3cH + Pm3¯m → Pm3...

The discovery of 2D ferromagnetic (FM) van der Waals (vdW) semiconductors with narrow bandgap and p‐type transport behavior makes them promising for infrared photodetection. Here, a 2D vdW heterodiode uncooled long‐wave infrared (LWIR) photodetector by stacking a p‐type 2D FM material CrSiTe3 on top of an n‐type transition metal dichalcogenides (TM...

Metal phosphorous tri‐chalcogenides are a category of new ternary 2D layered materials with a wide range of tuneable bandgaps (1.2–3.5 eV). These wide‐bandgap semiconductors exhibit great potential applications in solar‐blind ultraviolet (SBUV) photodetection. However, these 2D solar‐blind photodetectors suffer from low photoresponsivity, slow phot...

Defect engineering plays a complex role in modulating macroscopic performance in ferroelectric ceramics. Establishing Vpb′′−Vo∙∙ defect complex in nitrogen–annealed (NA) Pb0.9Ba0.1ZrO3 sample is found to significantly boost ferroelectricity and resistivity and it features a high peak-to-peak strain value (Sp-p ~ 0.132 %), which is 175% larger than...

Bismuth ferrite–based ferroelectric ceramics are considered strong competitors in high–temperature piezoelectric applications that benefits from their high depolarization temperature (Td), but problems of large conductivity and low piezoelectric coefficient (d33) should be tackled. BiFeO3–PbTiO3–x(Sr0.7Bi0.2□0.1)TiO3 (BF–PT–xSBT) ternary system are...

The PMN-28PT-xDy (x = 0, 1, 2, 3 and 4%) piezoelectric ceramics were prepared by the two-step sintering method. A high piezoelectric coefficient d33 ∼ 1270 pC/N is achieved when x = 3%. As the Dy doping content increases, the domain configuration transforms from ordered stripe-domains to disordered watermark-domains, while the average domain size d...

Composition dependent transitions from normal ferroelectrics to non-ergodic and finally to ergodic relaxor phase are observed in 0.7(Sr0.7Bi0.2□0.1)TiO3–(0.3-x)PbTiO3–xBi(Mg0.5Ti0.5)O3 system (SBT–PT–xBMT, □ represents A–site vacancy). Rietveld refinement results show that with increasing BMT content, the system experiences a gradual transition fro...

Piezo-photocatalytic technique is a new-emerging strategy to alleviate photoinduced charge recombination and thus enhance catalytic performance. The heterojunction construction engineering is a powerful approach to improve photocatalytic performance. Herein, the BiOCl/NaNbO3 with different molar ratios piezoelectric composites were successfully syn...

Paraelectric-ferroelectric-antiferroelectric (PE-FE-AFE) phase transitions induced by external stimulus (temperature, electric field, and hydrostatic pressure) usually produce exotic performances in functional ceramics. This Letter reports an isothermal phase transition in (Pb0.95Ba0.05)ZrO3 ceramics in the proximity of separated PE-FE and FE-AFE p...

Unique structure and performance in prominent high-entropy ceramics (HECs) have attracted enormous attentions recently. In this work, we have successfully synthesized pure-phase (Bi1/6Na1/6Sr1/6Ba1/6Pb1/6Ca1/6)TiO3 (BNSBPC) and (Bi1/6La1/6Na1/6K1/6Sr1/6Ba1/6)TiO3 (BLNKSB) HECs by conventional solid-state method. Rietveld refinement results show tha...

The materials processing history has a great influence on their properties and finally, determine their application effect. In this paper, the ferroelectric, polarization current, and strain properties of Mn-doped 0.75Pb(Mg1/3Nb2/3)O3-0.25PbTiO3 ceramics were studied in fresh state, aged state, and poled state, respectively. Compared with the symme...

In this study, a large electrocaloric effect (ECE) of 0.49 K with an ultrawide temperature span of 80 °C ranging from −15 to 65 °C (0.49 K ± 10%) was reported in the 0.94(0.80NaNbO3–0.20BaTiO3)–0.06Bi0.5Na0.5TiO3 composition. The incorporation of Bi0.5Na0.5TiO3 (BNT) into the NaNbO3–BaTiO3 matrix induced a ferroelectric-to-relaxor (FR) phase transi...

Two-dimensional (2D) materials with excellent optoelectronic properties have attracted tremendous research interest in recent years. The promising performances of photodetectors based on 2D materials, such as ultrafast photoresponse and ultrahigh photoresponsivity, have been demonstrated in the visible to short-wavelength infrared spectrum range (0...

In this work, we elaborately explored relationships between phase structure, dielectric and ferroelectric performances in (Pb, Ba)ZrO3 system to clarify its confusing characteristics. 1) Incorporation of barium decreased phase transition temperature, and orthorhombic–orthorhombic + rhombohedral–pseudocubic phase transition sequence was determined f...

Ag0.91Sm0.03NbO3-modified Na0.5Bi0.5TiO3–BaTiO3 ceramics (0.94−x)Na0.5Bi0.5TiO3–0.06BaTiO3–x(Ag0.91Sm0.03)NbO3 (x = 0, 0.03, 0.06, and 0.09) were prepared by solid-state reaction method. The structural, dielectric, and energy storage properties of the ceramics were systematically studied. Our results indicate that all ceramics exhibit pure perovski...

Exploring eco-friendly energy-storage ceramics simultaneously featuring large recoverable energy storage den�sity (Wrec), high energy storage efficiency (ƞ), and excellent temperature/frequency stabilities is highly desirable for the applications of pulsed power systems. Herein, AgNb0.85Ta0.15O3 was used to modify Na0.5Bi0.5TiO3 based lead-free r...

Ferroelectric materials exhibit anomalous behavior due to the presence of domains and domain walls which are related to the spontaneous polarization inherent in the crystal structure. Control of ferroelectric domains and domain walls has been used to enhance device performances in ultrasound, pyroelectric detectors, and photovoltaic systems with re...

In this work, (Bi0.5K0.5)1-xSrxTiO3 compositions (x = 0.03∼0.18) are designed to clarify the role of normal-relaxor ferroelectric phase transition and morphotropic phase boundary on dielectric, piezoelectric and electrostrain properties. With increasing strontium content, tetragonal distortion decreases and tetragonal and pseudocubic phases coexist...

Relaxor ferroelectric 0.75 Pb(Mg1/3Nb2/3)O3-0.25PbTiO3 (0.75PMN-0.25PT) ceramics with Mn-doping concentration of 0%, 1%, 2% and 3 mol% were prepared by two-step sintering. The phase composition, microstructure, dielectric property, ferroelectric property, piezoelectric property and electromechanical property were investigated. Results indicate that...

The influence of La³⁺-doping on the electrocaloric effect (ECE) of the 0.75(Pb1-3x/2Lax)(Mg1/3Nb2/3)O3-0.25(Pb1-3x/2Lax)TiO3 (L-PMN-PT: x/75/25 x = 0.0–4.0 mol.%) ceramics was studied. With the increase of La³⁺-doping in these ceramics, the relaxor ferroelectric properties increase, while the average grain size, coercive field Ec and Curie temperat...

In this study, a ceramic with a 0.7Bi0.5K0.5TiO3-0.3SrTiO3 composition was designed to enhance its energy storage performance via rolling technology. Temperature had a great influence on microstructural refinement and energy storage density. A high recoverable energy storage density of 2.31 J/cm³ and efficiency of 77.7% were obtained under an optim...

The pseudo-first-order phase transition in 0.94Bi0.5Na0.5TiO3-0.06BaTiO3 ceramics leads to a sharp increase in temperature change (ΔT) in the vicinity of the ferroelectric-to-relaxor transition temperature TFR (~100 °C) [Appl. Phys. Lett. 110 (2017) 182904]. In this study, we add the 0.78Bi0.5Na0.5TiO3-0.06BaTiO3-0.16(Sr0.7Bi0.2)TiO3 relaxor phase...

This work directly tests electrocaloric effect (ECE) of (0.94-x)Bi0.5Na0.5TiO3–0.06BaTiO3–xSrZrO3 (BNBTSZx) with x = 0 (SZ0), x = 0.01 (SZ0.01), x = 0.02 (SZ0.02) and x = 0.03 (SZ0.03) at different temperature points. The Sr²⁺ and Zr⁴⁺ are introduced into 0.94Bi0.5Na0.5TiO3–0.06BaTiO3 to convert nonergodic relaxor phase into ergodic relaxor phase a...

The 0.5 wt% MnO2‐doped 0.95(K0.5Na0.5)(Nb0.965Sb0.035)O3‐0.01CaZrO3‐0.04(Bi0.5K0.5)(Hf0.98Ti0.02)O3 (95KNNS‐1CZ‐4BKHT) lead‐free ceramics with grain size from 0.31 to 3.83 µm are fabricated by hot‐press sintering (HPS), microwave sintering (MS), conventional sintering (CS), two‐step sintering (TSS), and a combination of two of the above‐mentioned m...

Recently, bismuth-based perovskite-type ceramics are considered as promising species in energy storage applications because of easy phase- and micro/macro-structure modulations and high performances. In this work, composition dependent phase structure and ferroelectric properties in novel Bi0.5K0.5TiO3-Ba(Mg1/3Nb2/3)O3 (BKT-BMN) ceramics are studie...

With close attention being paid to environmental issues and more legislation coming into force to limit the application of Pb-based materials, accelerating research on lead-free piezoelectric ceramics has become increasingly requisite and urgent. Herein, we have devised and synthesized (1-x)(K0.5Na0.5)0.98Ag0.02(Nb0.96Sb0.04)O3-x(Bi0.5Na0.5)ZrO3 [a...

Lead-free (1-x) Bi0.2Sr0.7TiO3-xBiFeO3 (x = 0-0.4, denoted as BST-xBFO) thin films were deposited on Pt(111)/Ti/SiO2/Si substrates by sol-gel/spin coating technique and their microstructures, dielectric properties and energy storage were investigated in detail. A single perovskite phase and high-dense microstructure are obtained in all thin films....

With industrializations speeding up, the need for materials with multiple functions are growing because of ever-increasing complexity of electronic devices. The BiFeO3- based ferroelectric relaxor ceramic as a multifunctional material has been ignored thus far. This work innovatively investigates the multifunctionality in a novel lead-free BiFeO3-B...

Electrocaloric effect (ECE) offers a promising method for highly efficient and environment-friendly solid-state refrigeration. To obtain giant EC temperature change (ΔT), high electric field and temperature are usually applied to ECE materials, but few investigations have been done on the influence of Joule heating on ECE caused by leakage current...

A novel 0–3 type (Bi 0.32 Sr 0.42 Na 0.20 )TiO 3 /MgO composite is investigated in this work, which possesses a high stored energy storage density w s ˜2.50 J/cm ³ , recoverable energy storage density W R ˜2.09 J/cm ³ with high efficiency η˜84% under low electric field (20 kV/mm). The excellent performance is owning to the increase of breakdown str...