Showing papers by "Anvar A. Zakhidov published in 2018"
TL;DR: It is demonstrated that the halide perovskite nanoantennas can emit light in the range of 530-770 nm depending on their composition, and a simple technique based on laser ablation of thin films prepared by wet-chemistry methods is employed as a novel cost-effective approach for the fabrication of resonant perovkite nanostructures.
Abstract: Nanoantennas made of high-index dielectrics with low losses in visible and infrared frequency ranges have emerged as a novel platform for advanced nanophotonic devices. On the other hand, halide perovskites are known to possess high refractive index, and they support excitons at room temperature with high binding energies and quantum yield of luminescence that makes them very attractive for all-dielectric resonant nanophotonics. Here we employ halide perovskites to create light-emitting nanoantennas with enhanced photoluminescence due to the coupling of their excitons to dipolar and multipolar Mie resonances. We demonstrate that the halide perovskite nanoantennas can emit light in the range of 530-770 nm depending on their composition. We employ a simple technique based on laser ablation of thin films prepared by wet-chemistry methods as a novel cost-effective approach for the fabrication of resonant perovskite nanostructures.
129 citations
TL;DR: In this paper, solution-processed organic-inorganic lead halide perovskites have been proposed as promising gain media for tunable semiconductor lasers, but they are not suitable for continuous-wave lasing at room temperature.
Abstract: Solution-processed organic–inorganic lead halide perovskites have recently emerged as promising gain media for tunable semiconductor lasers. However, optically pumped continuous-wave lasing at room...
119 citations
TL;DR: The observed observation of broadly tunable Fano resonances in halide perovskite nanoparticles originating from the coupling of excitons to the Mie resonances excited in the nanoparticles paves the way to an efficient control of emission properties of on-chip-integrated light-emitting nanoantennas.
Abstract: © 2018 American Chemical Society. Halide perovskites are known to support excitons at room temperatures with high quantum yield of luminescence that make them attractive for all-dielectric resonant nanophotonics and meta-optics. Here we report the observation of broadly tunable Fano resonances in halide perovskite nanoparticles originating from the coupling of excitons to the Mie resonances excited in the nanoparticles. Signatures of the photon-exciton ("hybrid") Fano resonances are observed in dark-field spectra of isolated nanoparticles, and also in the extinction spectra of aperiodic lattices of such nanoparticles. In the latter case, chemical tunability of the exciton resonance allows reversible tuning of the Fano resonance across the 100 nm bandwidth in the visible frequency range, providing a novel approach to control optical properties of perovskite nanostructures. The proposed method of chemical tuning paves the way to an efficient control of emission properties of on-chip-integrated light-emitting nanoantennas.
91 citations
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TL;DR: In this paper, a surface emitting distributed feedback methylammonium lead iodide (MAPbI3) perovskite laser on silicon substrate, at room temperature under continuous-wave optical pumping, in ambient air environment, is reported.
Abstract: Solution-processed organic-inorganic lead halide perovskites have recently emerged as promising gain media for tunable semiconductor lasers, and have come to rival inorganic III-V group semiconductors as the material candidate for chip-scale lasers. Although electrically pumped lasing at room temperature is the ultimate goal, optically pumped continuous-wave lasing at room temperature,a prerequisite for a laser diode,has not been achieved so far. Here, we report lasing action in a surface emitting distributed feedback methylammonium lead iodide (MAPbI3) perovskite laser on silicon substrate, at room temperature under continuous-wave optical pumping, in ambient air environment. This outstanding performance is achieved by the ultra-low lasing threshold of 13 W/cm2, which is enabled by the thermal nanoimprint lithography that directly patterns perovskite into a high Q cavity with large mode confinement, while at the same time improves perovskite emission characteristics. Our results represent a major step toward the realization of perovskite laser diodes, which is essential in the future insertion of perovskite lasers into photonic integrated circuits, for applications in optical computing, sensing and on-chip quantum information.
65 citations
TL;DR: In this paper, the authors describe the properties of thermoelectric (TE) materials: abundance, low thermal conductivity, and non-toxicity, which is of high interest in the field of TE materials.
Abstract: Polymer-based composites are of high interest in the field of thermoelectric (TE) materials because of their properties: abundance, low thermal conductivity, and nontoxicity. In applications, like ...
45 citations
41 citations
TL;DR: In this paper, a dual-hard-templating technique was proposed for constructing 3D ordered macro-mesoporous materials by nanocasting mesoporous silica confined within the regular voids of a silica colloidal crystal.
Abstract: Three-dimensionally (3D) ordered macro-/mesoporous (3DOM/m) materials, which combine the advantages of high surface area of the mesopores, efficient mass transport within the macropores, and strong structural stability of the 3D interconnected porous frameworks, have shown remarkable performances in a wide range of applications Herein, we demonstrate a novel dual-hard-templating technique as a general synthetic strategy for constructing the 3DOM/m materials by nanocasting mesoporous silica confined within the regular voids of a silica colloidal crystal (opal) Through this method, various materials, such as 3DOM/m Pt, Pd, Ni2P, carbon and N/P codoped carbon (NPC), have been successfully synthesized The as-prepared 3DOM/m Ni2P and NPC are demonstrated to exhibit outstanding electrocatalytic performance for the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR), respectively
40 citations
TL;DR: A directly patterned perovskite distributed feedback (DFB) resonator is reported and narrow amplified spontaneous emission (ASE) at pump powers as low as 0.1 W/cm2 under continuous-wave optical pumping conditions at room temperature.
Abstract: We report a directly patterned perovskite distributed feedback (DFB) resonator and show narrow amplified spontaneous emission (ASE) at pump powers as low as 01 W/cm2 under continuous-wave (CW) optical pumping conditions at room temperature Compared to the pristine thin film photoluminescence spectrum, a 16-fold reduction in emission linewidth in the MAPbI3 DFB cavity was observed The direct nanostructuring of perovskites was achieved by thermal nanoimprint lithography Our findings pave the way toward realizing CW pumped perovskite lasers at room temperature and energy-efficient perovskite light sources
28 citations
TL;DR: In this article, an organic-based or polymer-based thermoelectric (TE) system is proposed to convert wasted heat energy into electricity, which can convert waste heat energy to electricity.
26 citations
TL;DR: The results demonstrate that the CNT scaffolds demonstrated-which are easily tuneable to form sheets/fibers-support growth, proliferation, and spatial organization of pancreatic cancer cells, indicating their great potential in cancer tissue engineering.
Abstract: Novel synthetic biomaterials able to support, direct tissue growth and retain cellular phenotypical properties are promising building blocks for the development of tissue engineering platforms for accurate and fast therapy screening for cancer. The aim of this study is to validate an aligned, pristine multi-walled carbon nanotube (CNT) platform for in vitro studies of pancreatic cancer as a systematic understanding of interactions between cells and these CNT substrates is lacking. Our results demonstrate that our CNT scaffolds -which are easily tuneable to form sheets/fibres- support growth, proliferation and spatial organisation of pancreatic cancer cells, indicating their great potential in cancer tissue engineering.
16 citations
TL;DR: In this article, an array of silver nanoantennas supporting collective modes was proposed to provide subwavelength light enhancement in the substrate of a typical organic thin-film solar cell.
Abstract: In this paper, we study experimentally the enhancement of parameters of a typical organic thin film solar cell (OSC) achieved by an originally proposed light trapping structure (LTS). Our LTS is an array of silver nanoantennas supporting collective modes, what provide subwavelength light enhancement in the substrate. Low losses in the metal result from the advantageous optical field distribution that is achieved in the broad range of wavelengths. We study the enhancement of all the main photovoltaic (PV) parameters observed in OSC with our LTS, such as power conversion efficiency (PCE), which is effectively increased by 18%, fill factor (FF), that can also be effected positively and short-circuit current Isc improvement. Although the Ag nanoantenna occupies up to 40% of the photoactive OSC area, it provides the nearly twice enhanced optical absorption, resulting in overall higher Isc and FF. Improvements of the optical and electrical design of OSC architectures are discussed for further enhancement of per...
TL;DR: In this paper, the photo-induced process of change in optical properties in resonant hybrid perovskite nanoparticles with a mixed anion composition (MAPbBr1.5I1.
Abstract: Organic–inorganic perovskites with a mixed anion composition are widely used in solar cells, light-emitting diodes, and nanophotonic structures. Light nanosources based on resonant perovskite nanoparticles are of particular interest. However, perovskites with such a composition demonstrate the light-induced segregation of anions, which leads to a reversible dynamic rearrangement of the optical properties of a material and photoluminescence spectra. In this work, the photoinduced process of change in optical properties in resonant hybrid perovskite nanoparticles with a mixed anion composition (MAPbBr1.5I1.5, where MA = NH3CH
3
+
) has been studied. Comparison with a similar process in a perovskite thin film with a similar composition has shown that the photoinduced migration of halogen ions in a nanoparticle occurs cyclically. This is due to the competition of two processes: the concentration of ions near the boundaries of the particle and migration caused by the gradient of the density of light-generated electron–hole pairs. This effect in resonant nanoparticles makes it possible to obtain optically tunable nanoantennas.
TL;DR: In this paper, a meso-superstructured organometal halide perovskite solar cells, incorporating resonant silicon nanoparticles between mesoporous TiO2 transport and active layers, is demonstrated.
Abstract: Implementation of resonant colloidal nanoparticles for improving performance of organometal halide perovskites solar cells is highly prospective approach, because it is compatible with the solution processing techniques used for any organic materials. Previously, resonant metallic nanoparticles have been incorporated into perovskite solar cells for better light absorption and charge separation. However, high inherent optical losses and high reactivity of noble metals with halides in perovskites are main limiting factors for this approach. In turn, low-loss and chemically inert resonant silicon nanoparticles allow for light trapping and enhancement at nanoscale, being suitable for thin film photovoltaics. Here photocurrent and fill-factor enhancements in meso-superstructured organometal halide perovskite solar cells, incorporating resonant silicon nanoparticles between mesoporous TiO2 transport and active layers, are demonstrated. This results in a boost of the device efficiency up to 18.8\% and fill factor up to 79\%, being a record among the previously reported values on nanoparticles incorporation into CH3NH3PbI3 (MAPbI3) perovskites based solar cells. Theoretical modeling and optical characterization reveal the significant role of Si nanoparticles for increased light absorption in the active layer rather than for better charge separation. The proposed strategy is universal and can be applied in perovskite solar cells with various compositions, as well as in other optoelectronic devices.
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TL;DR: The ionic gating concept demonstrated here for most simple classical planar small-molecule OPV cells can be potentially applied to more complex highly efficient hybrid devices, such as perovskite photovoltaic with an ETL or a hole transport layer, providing a new way to tune their properties via controllable and reversible interfacial doping of charge collectors and transport layers.
Abstract: We demonstrate an improvement in the performance of organic photovoltaic (OPV) systems based on small molecules by ionic gating via controlled reversible n-doping of multi-wall carbon nanotube (MWCNT) coated on fullerenes ETL: C60 and C70. Such electric double layer charging (EDLC) doping, achieved by ionic liquid (IL) charging, allows tuning the electronic concentration in MWCNT and in the fullerene planar acceptor layers, increasing it by orders of magnitude. This leads to decreasing the series and increasing the shunt resistances of OPV and allows to use of thick (up to 200 nm) ETLs, increasing the durability and stability of OPV. Two stages of OPV enhancement are described, upon the increase of gating bias Vg: at small (or even zero) Vg the extended interface of IL and porous transparent MWCNT is charged by gating, and the fullerene charge collector is significantly improved, becoming an ohmic contact. This changes the S-shaped I-V curve via improving the electron collection by n-doped MWCNT cathode with ohmic interfacial contact. The I-V curves further improve at higher gating bias Vg due to the raising of the Fermi level and lowering of MWCNT work function. At the next qualitative stage, the acceptor fullerene layer becomes n-doped by electron injection from MWCNT while ions of IL penetrate into fullerene. At this step the internal built-in field is created within OPV, which helps exciton dissociation and charge separation/transport, increasing further the Jsc and the FF (Fill factor). Overall power conversion efficiency (PCE) increases nearly 50 times in CuPc/fullerene OPV with MWCNT cathode. The concept of ionically gated MWCNT-ETL interface is numerically simulated by the drift-diffusion model which allows to fit the observed I-V curves.
TL;DR: In this article, the possibility of obtaining a synthetic hydroxyapatite of calcium from a biological waste material is shown, and the characteristics influencing the synthesis process are studied based on the results of the X-ray analysis and the obtained electron microscope images.
Abstract: In this paper, the possibility of obtaining a synthetic hydroxyapatite of calcium from a biological waste material is shown. The characteristics influencing the synthesis process are studied. Based on the results of the X-ray analysis and the obtained electron microscope images, it can be concluded that the synthesized HAP has a Ca/P ratio of 1.5 and with crystals with an average size of 2 microns. In work, experiments on obtaining biologically soluble films based on nanoscale polymer fibers and calcium hydroxyapatite were carried out. As a result, the main parameters of the process for the electroforming of nano-sized fibers with HAP are determined. The proposed method allows the laying of strictly directed nanofibers from a polymer with a diameter of 50 to 500 nm. The use of different types of electrodes makes it possible to vary the size of nanofibers. The characteristics such as solution viscosity, high voltage and optimum parameters were selected, which allowed obtaining films from biologically soluble polymer nanofibers and HAP. Also, experiments were conducted to introduce medicines into the film structure.
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28 May 2018
TL;DR: In this article, the authors demonstrate the controlled n-doping in small molecule organic photovoltaic (OPV) systems by ionic gating of multi-wall carbon nanotube (MWCNT) coated fullerenes.
Abstract: We demonstrate the controlled n-doping in small molecule organic photovoltaic (OPV) systems by ionic gating of multi-wall carbon nanotube (MWCNT) coated fullerenes: $C_{60}$ and $C_{70}$. Such electric double layer charging (EDLC) doping, achieved by ionic liquid (IL) charging, allows tuning the electronic concentration in the acceptor layers, increasing it by orders of magnitude. This leads to decreasing both the series and shunt resistances of OPV and allows to use thick (up to 200 nm) electron transport layers, increasing the durability and stability of OPV. Two stages of OPV enhancement are described, upon increase of gating bias: at small (or even zero) $V_g$ the interface between porous transparent MWCNT charge collector with fullerene is improved, becoming an ohmic contact. This changes the S-shaped I-V curve and improves the electrons collection by a MWCNT turning it into a good cathode. The effect further enhances at higher $V_g$ due to raising of Fermi level and lowering of MWCNT work function. At next qualitative stage, the acceptor layer becomes n-doped by electron injection from MWCNT and ions penetration into fullerene. At this step the internal built-in field is created within OPV, that helps exciton dissociation and charge separation/transport, increasing further the $I_{sc}$ and the $FF$ (Filling factor). Overall power conversion efficiency (PCE) increases nearly 50 times in classical CuPc/fullerene OPV with bulk heterojunction photoactive layer and MWCNT cathode. Ionic gating of MWCNT-fullerene part of OPV opens a new way to tune the properties of organic devices, based on controllable and reversible doping and modulation of work function.
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TL;DR: An overview of the recent progress in the study of optical effects originating from nanostructured perovskites, including their potential applications, can be found in this article, where the authors provide an overview of their work.
Abstract: Halide perovskites have emerged recently as promising materials for many applications in photovoltaics and optoelectronics. Recent studies of their optical properties suggest many novel opportunities for a design of advanced nanophotonic devices due to low-cost fabrication, high values of the refractive index, existence of excitons at room temperatures, broadband bandgap tunability, high optical gain and nonlinear response, as well as simplicity of their integration with other types of structures. This paper provides an overview of the recent progress in the study of optical effects originating from nanostructured perovskites, including their potential applications.
01 Sep 2018
TL;DR: In this article, low-loss and chemically inert resonant silicon nanoparticles (NPs) are added between electron transport layer and perovskite layer that allows to increase the efficiency enhancement via improved light harvesting, photocurrent, open-circuit voltage and fill-factor.
Abstract: Improving performance and stability of lead halide perovskites solar cells (PSC) is one of the most important direction in modern photovoltaics. For this purpose, we added low-loss and chemically inert resonant silicon nanoparticles (NPs) between electron transport layer and perovskite layer that allows to increase the efficiency enhancement via improved light harvesting, photocurrent, open-circuit voltage and fill-factor. This results in a boost of the device efficiency up to 18.8%, being a record among the previously reported results on nanoparticles incorporation into CH3NH3PbI3 (MAPbI3) perovskite-based solar cells. Moreover, PSC with the silicon NPs shows efficiency improvement in time with respect to the cells without NPs. The proposed method is simple and can be implemented for PSCs with various compositions and architectures.
01 Dec 2018
TL;DR: In this article, the authors demonstrate that the halide perovskite planar solar cells with the architecture of ITO/PEDOT:PSS/Perovskites/PCBM/LiF/Al show a switchable dual operation of descent photovoltaic and quite bright electroluminescence in visible range.
Abstract: We demonstrate that the halide perovskite planar solar cells with the architecture of ITO/PEDOT:PSS/Perovskite/PCBM/LiF/Al show a switchable dual operation of descent photovoltaic and quite bright electroluminescence in visible range. In our experiments, the active layer is made of a mixed halide perovskite (MAPbBr2I) and the device is properly cycled upon light and bias exposure. We argue that this curious effect of switchable double functionality between solar cell and light-emitting device in one architecture is caused by photoinduced segregation in the perovskite. It is shown that the bright red electroluminescence at low voltage of ~ 2 (3) eV appears only after cycling the device in PV regime. On the other hand, electroluminescence operation also effects the following PV mode. This effect is caused by redistribution of photoactivated ions I-/Br- and their vacancies during photoexcitation in PV regime.
04 May 2018
TL;DR: In this paper, the authors reported theoretical and experimental results for a high-Q cavity based on nano-imprinted perovskite film and revealed that bound state in the continuum transformed into a resonant state due to leakage into substrate leads to significant enhancement of the photoluminescence signal.
Abstract: Here we report theoretical and experimental results for a high-Q cavity based on nanoimprinted perovskite film. We reveal that bound state in the continuum transformed into a resonant state due to leakage into substrate leads to significant enhancement of the photoluminescence signal of the perovskite cavity.
13 May 2018
TL;DR: In this paper, the photoluminescence enhancement near the dipolar and multipolar Mie resonances for both visible and near-infrared frequency ranges was investigated for both nanoantennas and nanostructured metasurfaces made of halide perovskites.
Abstract: We study resonant properties of nanoantennas and nanostructured metasurfaces made of halide perovskites and demonstrate experimentally the photoluminescence enhancement near the dipolar and multipolar Mie resonances for both visible and near-infrared frequency ranges.
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TL;DR: In this paper, a dual functional device based on mixed halide perovskite CH3NH3PbBr2I can be switched from SC to LED with low threshold voltage Vth < 2 V by exposing to Sun at open circuit Voc or at small bias voltage of Vpol ~ 1 - 2 V.
Abstract: Organic-inorganic halide perovskites recently have emerged as a promising material for highly effective light-emitting diodes (LEDs) and solar cells (SCs). Despite efficiencies of both perovskite SCs and LEDs are already among the best, the development of a perovskite dual functional device that is capable of working in these two regimes with high efficiencies is still challenging. Here we demonstrate that the dual functional device based on mixed halide perovskite CH3NH3PbBr2I can be switched from SC to LED with low threshold voltage Vth < 2 V by exposing to Sun at open circuit Voc or at small bias voltage of Vpol ~ 1 - 2 V. Such photo-poling creates in-situ p-i-n junction via methylammonium (CH3NH3+, MA+) and I-/Br- ions migration to interfaces, lowering charge injection barriers, and self-balancing injection currents in perovskite LED. We show that before the photo-poling, the electroluminescence (EL) is highly unstable in LED regime, whereas after the photo-poling, stabilized EL exhibits unusual dynamics, increasing with time and poling cycle number, while Vth and injection current decrease with cycling runs. Additionally, photo-induced and current-induced halide segregation accumulates with cycling, that is found beneficial for LED, increasing its efficiency and brightness, but reversibly degrading photovoltaic (PV) performance, which can be easily recovered.
13 May 2018
TL;DR: In this article, the first directly patterned perovskite distributed feedback (DFB) resonator with a narrow amplified spontaneous emission (ASE) at pump powers as low as 0.1W/cm2, under continuous-wave (CW) optical pumping condition at room temperature.
Abstract: We report the first directly patterned perovskite distributed feedback (DFB) resonator with a narrow amplified spontaneous emission (ASE) at pump powers as low as 0.1W/cm2, under continuous-wave (CW) optical pumping condition at room temperature.
01 Dec 2018
TL;DR: In this article, low-loss and chemically inert resonant silicon nanoparticles between electron transport layer and perovskite layer were added to increase not only efficiency enhancement via improved light harvesting, photocurrent, open-circuit voltage and fill-factor, but also increase these characteristics in few days after device preparation.
Abstract: A lot of attempts were given to improve efficiency of lead halide perovskites solar cells in last several years by chemically active plasmonic nanoparticles implementation, but there is no data about stability in time. To solve both problem we added low-loss and chemically inert resonant silicon nanoparticles between electron transport layer and perovskite layer that allows to increase not only efficiency enhancement via improved light harvesting, photocurrent, open-circuit voltage and fill-factor, but also we increase these characteristics in few days after device preparation. Silicon nanoparticles allow achieve the device efficiency up to 18.8%, being a record among the previously reported results on nanoparticles incorporation into CH3NH3PbI3 (MAPbk3) perovskite-based solar cells. The proposed method of efficiency enhancement can be used for solar cells with various chemical compositions of perovskites.