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1.
ACS Appl Mater Interfaces ; 12(5): 6064-6073, 2020 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-31912720

RESUMO

Interface interactions between perovskite materials and substrates are of great significance for the development of high-quality perovskite materials. Herein, we have successfully prepared Cs2AgBiBr6 double-perovskite films via a one-step spin-coating process and demonstrated a novel approach that modifies the surface of substrates with an ultrathin metal oxide (MOx) layer to promote the film quality and photoelectric performance. Characterization results strongly suggest that the improvement is attributed to the Bi-O interfacial interaction at substrate/perovskite interface. Benefiting from this interface interaction, the average grain size of Cs2AgBiBr6 films has remarkably risen up to ∼500 nm, which is nearly four times larger than the one directly deposited on a commercial fluorine-doped tin oxide substrate. Meanwhile, the pin hole surface area ratio has reduced from 2.61 to 0.60%. Furthermore, the corresponding photodetectors (PDs) have been fabricated and the performance has significantly improved owing to the enhanced Cs2AgBiBr6 film quality. The on-off ratio of the optimized PD has a boost of almost 10 times. In addition, the minimum detected irradiation has decreased from 9.7 × 10-8 to 1.9 × 10-9 W cm-2, as well as the maximum detectivity has increased from 3.3 × 1011 to 1.2 × 1013 Jones. These results suggest a feasible method for crystallization improvement of double-perovskite films and indicate promising promotion of photoelectric performance.

2.
ACS Appl Mater Interfaces ; 11(46): 43376-43382, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31663717

RESUMO

Cuprite, nominally cuprous oxide (Cu2O) but more correctly Cu2-xO, is widely used in optoelectronic applications because of its natural p-type, nontoxicity, and abundant availability. However, the photoresponsivity of Cu2O/Si photodetectors (PDs) has been limited by the lack of high-quality Cu2-xO films. Herein, we report a facile room-temperature solution method to prepare high-quality Cu2-xO films with controllable x value which were used as hole selective transport layers in crystalline n-type silicon-based heterojunction PDs. The detection performance of Cu2-xO/Si PDs exhibits a remarkable improvement via reducing the x value, resulting in the optimized PDs with high responsivity of 417 mA W-1 and fast response speed of 1.3 µs. Furthermore, the performance of the heterojunction PDs can be further improved by designing the pyramidal silicon structure, with enhanced responsivity of 600 mA W-1 and response speed of 600 ns. The superior photodetecting performance of Cu2-xO/n-Si heterojunctions is attributed to (i) the matched energy level band alignment, (ii) the low trap states in high-quality Cu2O thin films, and (iii) the excellent light trapping. We expect that the low-cost, highly efficient solution process would be of great convenience for large-scale fabrication of the Cu2-xO thin films and broaden the applications of Cu2-xO-based optoelectronic devices.

3.
Angew Chem Int Ed Engl ; 58(41): 14740-14747, 2019 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-31496040

RESUMO

Metal-organic framework-derived NiCo2.5 S4 microrods wrapped in reduced graphene oxide (NCS@RGO) were synthesized for potassium-ion storage. Upon coordination with organic potassium salts, NCS@RGO exhibits an ultrahigh initial reversible specific capacity (602 mAh g-1 at 50 mA g-1 ) and ultralong cycle life (a reversible specific capacity of 495 mAh g-1 at 200 mA g-1 after 1 900 cycles over 314 days). Furthermore, the battery demonstrates a high initial Coulombic efficiency of 78 %, outperforming most sulfides reported previously. Advanced ex situ characterization techniques, including atomic force microscopy, were used for evaluation and the results indicate that the organic potassium salt-containing electrolyte helps to form thin and robust solid electrolyte interphase layers, which reduce the formation of byproducts during the potassiation-depotassiation process and enhance the mechanical stability of electrodes. The excellent conductivity of the RGO in the composites, and the robust interface between the electrodes and electrolytes, imbue the electrode with useful properties; including, ultrafast potassium-ion storage with a reversible specific capacity of 402 mAh g-1 even at 2 A g-1 .

4.
Nat Commun ; 10(1): 3687, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31417082

RESUMO

We herein demonstrate the unusual effectiveness of two strategies in combination to enhance photoelectrochemical water splitting. First, the work function adjustment via molybdenum (Mo) doping significantly reduces the interfacial energy loss and increases the open-circuit photovoltage of bismuth vanadate (BiVO4) photoelectrochemical cells. Second, the creation and optimization of the heterojunction of boron (B) doping carbon nitride (C3N4) and Mo doping BiVO4 to enforce directional charge transfer, accomplished by work function adjustment via B doping for C3N4, substantially boost the charge separation of photo-generated electron-hole pairs at the B-C3N4 and Mo-BiVO4 interface. The synergy between the above efforts have significantly reduced the onset potential, and enhanced charge separation and optical properties of the BiVO4-based photoanode, culminating in achieving a record applied bias photon-to-current efficiency of 2.67% at 0.54 V vs. the reversible hydrogen electrode. This work sheds light on designing and fabricating the semiconductor structures for the next-generation photoelectrodes.

5.
ACS Appl Mater Interfaces ; 11(35): 32097-32107, 2019 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-31408610

RESUMO

Kesterite Cu2ZnSn(S,Se)4 (CZTSSe) thin film is a promising material for optoelectronic devices. In this work, we fabricate Mo/CZTSSe/CdS/ZnO/ITO (ITO, indium tin oxide) heterojunction photodetectors with favorable self-powered characteristics. The photodetector exhibits exceptional high-frequency photoresponse performance whose -3 dB bandwidth and rise/decay time have reached 1 MHz and 240/340 ns, respectively. For further improvement, ultrathin Al2O3 layer prepared via atomic layer deposition (ALD) process is introduced at the Mo/CZTSSe interface. The influence of ALD-Al2O3 layer thickness and its role on the photoresponse performance are investigated in detail. The interfacial layer proved to serve as a protective layer preventing selenization of Mo electrode, resulting in the reduction of MoSe2 transition layer and the decrease of series resistance of the device. Accordingly, the -3 dB bandwidth is remarkably extended to 3.5 MHz while the rise/decay time is dramatically improved to 60/77 ns with 16 cycles of ALD-Al2O3 layer, which is 4-5 orders of magnitude faster than the other reported CZTSSe photodetectors. Simultaneously, it is revealed that the ALD-Al2O3 interfacial layer acts as an electron blocking layer which leads to the effective suppression of carrier recombination at the rear surface. Consequently, the responsivity and detectivity are enhanced in the entire range while the maximum values are up to 0.39 AW-1 and 2.04 × 1011 Jones with 8 cycles of ALD-Al2O3, respectively. Finally, the CZTSSe photodetector is successfully integrated into a visible light communication system and obtains a satisfying transfer rate of 2 Mbps. These results indicate the satisfying performance of CZTSSe-based thin film photodetectors with great potential applications for communication.

6.
Small ; 15(36): e1902135, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31322829

RESUMO

Self-powered photodetectors (PDs) based on inorganic metal halide perovskites are regarded as promising alternatives for the next generation of photodetectors. However, uncontrollable film growth and sluggish charge extraction at interfaces directly limit the sensitivity and response speed of perovskite-based photodetectors. Herein, by assistance of an atomic layer deposition (ALD) technique, CsPbBr3 perovskite thin films with preferred orientation and enlarged grain size are obtained on predeposited interfacial modification layers. Thanks to improved film quality and double side interfacial engineering, the optimized CsPbBr3 (Al2 O3 /CsPbBr3 /TiO2 , ACT) perovskite PDs exhibit outstanding performance with ultralow dark current of 10-11 A, high detectivity of 1.88 × 1013 Jones and broad linear dynamic range (LDR) of 172.7 dB. Significantly, excellent long-term environmental stability (ambient conditions >100 d) and flexibility stability (>3000 cycles) are also achieved. The remarkable performance is credited to the synergistic effects of high carrier conductivity and collection efficiency, which is assisted by ALD modification layers. Finally, the ACT PDs are successfully integrated into a visible light communication system as a light receiver on transmitting texts, showing a bit rate as high as 100 kbps. These results open the window of high performance all-inorganic halide perovskite photodetectors and extends to rational applications for optical communication.

7.
ACS Nano ; 13(7): 8246-8255, 2019 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-31244031

RESUMO

With the rapid advancement in different kinds of portable electronics, self-powered systems with small volume and high-performance characteristics have attracted great attention in recent years. It would be rather exciting if one integrated system can not only convert recyclable energy or waste to electricity but also store energy at the same time. Here, flexible all-in-one energy chips composed of urea-based photocatalytic fuel cells (PFCs) and asymmetric microsupercapacitors (AMSCs) are designed on the same plane for powering small portable electronics. The planar PFC consisting of TiO2 photoanode and Ag counter electrode, utilizing urea as fuel, can produce a stable energy output (highest power density of 3.04 µW cm-2 in 1 M urea solution under a UV intensity of 30 mW cm-2) while purify this wasted water simultaneously. Besides, the AMSC comprised of NiCoP@NiOOH positive electrode and zeolite imidazolide framework derived carbon (ZIF-C) negative electrode achieves a high areal capacitance of 54.7 mF cm-2 at 0.5 mA cm-2 and an excellent energy density of 13.9 µWh cm-2 at the power density of 270.5 µW cm-2. Its stability can be confirmed by 86% capacitance retention after 8000 electrochemical cycles and almost no decay after 500 bending cycles. Four PFCs and two AMSCs can be easily constructed into an energy chip and power small electronics. This eco-friendly and self-sustainable system has great potential in future portable electronics.

8.
ACS Appl Mater Interfaces ; 11(22): 20157-20166, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-31070353

RESUMO

The Cu(In,Ga)Se2 (CIGS) thin film has been commercialized as solar cells with great success, but its application for photodetectors still faces some practical challenges, including low detectivity and long response time. In this paper, the structure of the Mo/CIGS/CdS/ZnO/ITO heterojunction has been fabricated, and satisfactory performances of high detectivity and fast response time have been achieved by suppressing the dark current and enhancing the carrier mobility. The controllable growth of CIGS grains is accomplished through optimizing the selenization process, demonstrating that bigger grain sizes resulted in higher carrier mobility and better response characteristics. Particularly, the high rise/decay speed of 3.40/6.46 µs is achieved. Furthermore, the interface of the CIGS/CdS heterojunction has been modified by the Al2O3 layer via the atomic-layer deposition (ALD) process. The dark current of the device is effectively suppressed by the ALD-Al2O3 layer, which remarkably drops from ∼10-7 to ∼10-9 A. As a consequence, the detectivity rises from 3.08 × 1011 to 1.84 × 1012 Jones. In addition, the ALD-Al2O3 layer shows a protective effect as well, which is positive for photoelectrical conversion. Besides, the wide linear dynamic range of 102.1 dB and large -3 dB bandwidth of 78 kHz are acquired. This work suggests that the CIGS-based heterojunction has great potential for high-performance thin-film photodetectors.

9.
ACS Appl Mater Interfaces ; 11(17): 15581-15590, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30969099

RESUMO

On account of the large radius of K-ions, the electrodes can suffer huge deformation during K-ion insertion and extraction processes. In our work, we unveil the impact of using carboxymethyl cellulose (CMC) instead of poly(vinylidene fluoride) (PVDF) as binders for K-ion storage. Our porous hollow carbon submicrosphere anodes using the CMC binder exhibit a reversible capacity of 208 mA h g-1 after 50 cycles at 50 mA g-1, and even at a high current density of 1 A g-1, they achieve a reversible capacity of 111 mA h g-1 over 3000 cycles with almost no decay, demonstrating remarkably improved reversibility and cycling stability than those using PVDF (18 mA h g-1 after 3000 cycles at 1 A g-1). It is showed that the CMC binder can result in higher adhesion force and better mechanical performance than the PVDF binder, which can restrain the crack during a potassiation/depotassiation process. According to the test of adhesion force, the hollow carbon submicrospheres using the CMC binder show above three times of average adhesion force than that using the PVDF binder. Furthermore, based on the rational design, our hollow carbon submicrospheres also exhibit 62.3% specific capacity contribution below 0.5 V vs K/K+ region, which is helpful to design the full cell with high energy density. We believe that our work will highlight the binder effect to improve the K-ion storage performance.

10.
Nanoscale ; 10(36): 17092-17098, 2018 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-30179245

RESUMO

K-ion batteries (KIBs) have become one of the promising alternatives to lithium ion batteries. In this work, we are the first to utilize reduced graphene oxide (RGO) wrapped metal organic framework-derived FeS2 hollow nanocages (FeS2@RGO) as an anode for KIBs. Owing to the synergistic effect from FeS2 nanocages and RGO shells, our FeS2@RGO sample exhibited superior electrochemical performance. Such FeS2@RGO electrodes demonstrate a high capacity of 264 mA h g-1 after 50 cycles at 50 mA g-1 and 123 mA h g-1 after 420 cycles even at a large current density of 500 mA g-1. More importantly, we also explain the electrochemical reaction process about FeS2 and believe that these results would open the door for a novel class of long cycling performance anode materials in the KIB field.

11.
Light Sci Appl ; 7: 34, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30839585

RESUMO

In situ and continuous monitoring of electrochemical activity is key to understanding and evaluating the operation mechanism and efficiency of energy storage devices. However, this task remains challenging. For example, the present methods are not capable of providing the real-time information about the state of charge (SOC) of the energy storage devices while in operation. To address this, a novel approach based on an electrochemical surface plasmon resonance (SPR) optical fiber sensor is proposed here. This approach offers the capability of in situ comprehensive monitoring of the electrochemical activity (the electrode potential and the SOC) of supercapacitors (used as an example). The sensor adopted is a tilted fiber Bragg grating imprinted in a commercial single-mode fiber and coated with a nanoscale gold film for high-efficiency SPR excitation. Unlike conventional "bulk" detection methods for electrode activity, our approach targets the "localized" (sub-µm-scale) charge state of the ions adjacent to the electrode interface of supercapacitors by monitoring the properties of the SPR wave on the fiber sensor surface located adjacent to the electrode. A stable and reproducible correlation between the real-time charge-discharge cycles of the supercapacitors and the optical transmission of the optical fiber has been found. Moreover, the method proposed is inherently immune to temperature cross-talk because of the presence of environmentally insensitive reference features in the optical transmission spectrum of the devices. Finally, this particular application is ideally suited to the fundamental qualities of optical fiber sensors, such as their compact size, flexible shape, and remote operation capability, thereby opening the way for other opportunities for electrochemical monitoring in various hard-to-reach spaces and remote environments.

12.
ACS Appl Mater Interfaces ; 9(39): 34085-34092, 2017 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-28884570

RESUMO

Because of the popularity of smart electronics, multifunctional energy storage devices, especially electrochromic supercapacitors (SCs), have attracted tremendous research interest. Herein, a solid-state electrochromic asymmetric SC (ASC) window is designed and fabricated by introducing WO3 and polyaniline as the negative and positive electrodes, respectively. The two complementary materials contribute to the outstanding electrochemical and electrochromic performances of the fabricated device. With an operating voltage window of 1.4 V and an areal capacitance of 28.3 mF cm-2, the electrochromic devices show a high energy density of 7.7 × 10-3 mW h cm-2. Meanwhile, they exhibit an obvious and reversible color transition between light green (uncharged state) and dark blue (charged state), with an optical transmittance change between 55 and 12% at a wavelength of 633 nm. Hence, the energy storage level of the ASC is directly related to its color and can be determined by the naked eye, which means it can be incorporated with other energy cells to visual display their energy status. Particularly, a self-powered and color-indicated system is achieved by combining the smart windows with commercial solar cell panels. We believe that the novel electrochromic ASC windows will have great potential application for both smart electronics and smart buildings.

13.
ACS Appl Mater Interfaces ; 9(35): 29699-29706, 2017 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-28812871

RESUMO

Scalable manufacturing of flexible, fiber-shaped energy-storage devices has enabled great technological advances in wearable and portable technology. Replacing inefficient oxides with inexpensive and high-performance oxynitrides with more favorable three-dimensional (3D) structures is critical if the practical applications of these technologies are to be realized. Here, we developed a facile and controllable approach for the synthesis of 3D porous micropillars of molybdenum oxynitride (MON), which exhibit high conductivity, robust stability, and excellent energy-storage properties. Our fiber electrode, containing a 3D hierarchical MON-based anode, yields remarkable linear and areal specific capacitances of 64.8 mF cm-1 and 736.6 mF cm-2, respectively, at a scan rate of 10 mV s-1. Moreover, a wearable asymmetric supercapacitor based on TiN/MON//TiN/MnO2 demonstrates good cycling stability with a linear capacitance of 12.7 mF cm-1 at a scan rate of 10 mV s-1. These remarkable electrochemical properties are mainly attributed to the synergistic effect between the chemical composition of oxynitride and the robust 3D porous structure composed of interconnected nanocrystalline morphology. The presented strategy for the controllable design and synthesis of novel-oxide-derived functional materials offers prospects in developing portable and wearable electronic devices. We also demonstrate that these fiber supercapacitors can be combined with an organic solar cell to construct a self-powered system for broader applications.

14.
Nanoscale ; 9(28): 9913-9920, 2017 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-28678289

RESUMO

A tri-layered photoelectrode for dye-sensitized solar cells (DSSCs) is assembled using single crystal hollow TiO2 nanoparticles (HTNPs), sub-micro hollow TiO2 mesospheres (SHTMSs) and hierarchical TiO2 microspheres (HTMSs). The bottom layer composed of single crystal hollow TiO2 nanoparticles serves to absorb dye molecules, harvest light due to its hollow structure and keep a better mechanical contact with FTO conducting glass; the middle layer consisting of sub-micro hollow mesospheres works as a multifunctional layer due to its high dye adsorption ability, strong light trapping and scattering ability and slow recombination rates; and the top layer consisting of hierarchical microspheres enhances light scattering. The DSSCs made of photoanodes with a tripartite-layer structure (Film 4) show a superior photoconversion efficiency (PCE) of 9.24%, which is 7.4% higher than a single layered photoanode composed of HTNPs (Film 1: 8.90%), 4.6% higher than a double layer-based electrode consisting of HTNPs and SHTMSs (Film 2: 9.03%) and 2.6% higher than a double layer-based electrode made of HTNPs and HTMSs (Film 3: 9.11%). The significant improvements in the PCE for tri-layered TiO2 photoanodes are mainly because of the combined effects of their higher light scattering ability, long electron lifetime, fast electron transport rate, efficient charge collection and a considerable surface area with high dye-loading capability. This study confirms that the facile tri-layered photoanode is an interesting structure for high-efficiency DSSCs.

15.
ACS Nano ; 10(10): 9201-9207, 2016 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-27701868

RESUMO

The pursuit of harmonic combination of technology and fashion intrinsically points to the development of smart garments. Herein, we present an all-solid tailorable energy textile possessing integrated function of simultaneous solar energy harvesting and storage, and we call it tailorable textile device. Our technique makes it possible to tailor the multifunctional textile into any designed shape without impairing its performance and produce stylish smart energy garments for wearable self-powering system with enhanced user experience and more room for fashion design. The "threads" (fiber electrodes) featuring tailorability and knittability can be large-scale fabricated and then woven into energy textiles. The fiber supercapacitor with merits of tailorability, ultrafast charging capability, and ultrahigh bending-resistance is used as the energy storage module, while an all-solid dye-sensitized solar cell textile is used as the solar energy harvesting module. Our textile sample can be fully charged to 1.2 V in 17 s by self-harvesting solar energy and fully discharged in 78 s at a discharge current density of 0.1 mA.

16.
Adv Sci (Weinh) ; 3(6): 1500299, 2016 06.
Artigo em Inglês | MEDLINE | ID: mdl-27774405

RESUMO

Ultrahigh rates realized by ALD-made TiN. The symmetric full-cell supercapacitors deliver a typical capacitance of 20.7 F cm-3 at a scan rate of 1 V s-1, and retain 4.3 F cm-3 at high rate of 100 V s-1. The devices can be charged and discharged for 20 000 cycles with negligible capacitance loss and with an ultralow self-discharge current (≈1 µA).

17.
ACS Appl Mater Interfaces ; 8(29): 19158-67, 2016 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-27391382

RESUMO

UNLABELLED: Organic-inorganic hybrid heterojunctions are poised to push toward novel optoelectronics applications, such as photodetectors, but significant challenges complicating practical use remain. Although all organic based photodetectors have been reported with great success, their potential in high-speed, broadband, self-powered photodetectors have not been fully explored. Herein, a self-powered, broad bandwidth of photodetector based on PEDOT: PSS/Si heterojunction is built by a facial low temperature spin-coating method. By interface engineering of heterojunction with optimal band alignment and heteromicrostructures, enhanced photoresponse performances are obtained. The bandwidth of the hybrid photodetector could be broadened by 10 kHz after interfacial passivation by a methyl group. Further manipulating the geometrical structure of the hybrid heterojunction with silicon nanowire, a broad spectrum response from 300 to 1100 nm, with bandwidth as high as 40.6 kHz, fast response speed of 2.03 µs and high detection of 4.1 × 10(11) Jones under zero bias was achieved. Meanwhile, the close dependence between the photoresponse performance of heterojunctions and Si nanowire length is observed in the top-coverage configuration. Finally, a coverage effects model is proposed based on the competition of Si bulk and surface recombination, which is also confirmed by the designed bottom-coverage experiment. The mechanisms behind the enhanced photoresponse of the hybrid photodetector is attributed to the optimum band alignment, as well as the optimum balance of carrier dissociation and recombination of heterojunction. The scalable and low temperature method would be of great convenience for large-scale fabrication of the PEDOT: PSS/Si hybrid photodetector.

18.
ACS Appl Mater Interfaces ; 8(25): 16071-7, 2016 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-27275649

RESUMO

One of the most promising candidates for photoelectrochemical (PEC) water splitting photoanode is hematite (α-Fe2O3) due to its narrow bandgap and chemical stability. However, the poor bulk/surface kinetics of hematite limits its PEC performance. Herein, a facile two-step approach is reported to synergistically improve the PEC performance of Fe2O3. First, through bulk engineering of Ti doping, the photocurrent density of Ti-Fe2O3 photoanode (1.68 mA cm(-2) at 1.23 VRHE) shows a 3-fold increase compared with that of pure Fe2O3 photoanode (0.50 mA cm(-2) at 1.23 VRHE). Second, the photocurrent density of Ti-Fe2O3 photoanode could be further enhanced to 2.31 mA cm(-2) by surface engineering of FeOOH. The enhanced PEC water splitting performance is proposed to be the synergistic effect of bulk and surface engineering, which can be mainly attributed to the great increase of charge separation efficiency and surface transfer efficiency.

19.
Chem Commun (Camb) ; 52(37): 6296-9, 2016 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-27087032

RESUMO

We successfully fabricate flexible electrochromic supercapacitor (SC) electrodes employing novel flexible transparent conducting substrates. The as-synthesized flexible electrochromic SC electrodes exhibit great electrochemical performances (13.6 mF cm(-2), 138.2 F g(-1)) and high coloration efficiency (80.2 cm(2) C(-1)), which demonstrate their potential applications in flexible smart windows combining energy storage and electrochromism.

20.
ACS Appl Mater Interfaces ; 7(46): 25981-90, 2015 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-26544078

RESUMO

Photodetectors with a wide spectrum response are important components for sensing, imaging, and other optoelectronic applications. A molybdenum oxide (MoO(3-x))/Si heterojunction has been applied as solar cells with great success, but its potential in photodetectors has not been explored yet. Herein, a self-powered, high-speed heterojunction photodetector fabricated by coating an n-type Si hierarchical structure with an ultrathin hole-selective layer of molybdenum oxide (MoO(3-x)) is first investigated. Excellent and stable photoresponse performance is obtained by using a methyl group passivated interface. The heterojunction photodetector demonstrated high sensitivity to a wide spectrum from 300 to 1100 nm. The self-powered photodetector shows a high detectivity of (∼6.29 × 10(12) cmHz(1/2) W(-1)) and fast response time (1.0 µs). The excellent photodetecting performance is attributed to the enhanced interfacial barrier height and three-dimensional geometry of Si nanostructures, which is beneficial for efficient photocarrier collection and transportation. Finally, our devices show excellent long-term stability in air for 6 months with negligible performance degradation. The thermal evaporation method for large-scale fabrication of MoO(3-x)/n-Si photodetectors makes it suitable for self-powered, multispectral, and high-speed response photodetecting applications.

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