共查询到20条相似文献，搜索用时 15 毫秒
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Haotong Wei Hao Zhang Gan Jin Tianyi Na Guoyan Zhang Xue Zhang Yan Wang Haizhu Sun Wenjing Tian Bai Yang 《Advanced functional materials》2013,23(32):4035-4042
A water‐soluble conjugated polymer (WCP) poly[(3,4‐dibromo‐2,5‐thienylene vinylene)‐co‐(p‐phenylene‐vinylene)] (PBTPV), containing thiophene rings with high charge‐carrier mobility and benzene rings with excellent solubility is designed and prepared through Wessling polymerization. The PBTPV precursor can be easily processed by employing water or alcohols as the solvents, which are clean, environmentally friendly, and non‐toxic compared with the highly toxic organic solvents such as chloroform and chlorobenzene. As a novel photoelectric material, PBTPV presents excellent hole‐transport properties with a carrier mobility of 5 × 10?4 cm2 V?1 s?1 measured in an organic field‐effect transistor device. By integrating PBTPV with aqueous CdTe nanocrystals (NCs) to produce the active layer of water‐processed hybrid solar cells, the devices exhibit effective power conversion efficiency up to 3.3%. Moreover, the PBTPV can form strong coordination interactions with the CdTe NCs through the S atoms on the thiophene rings, and effective coordination with other nanoparticles can be reasonably expected. 相似文献
3.
Nathan D. Cottam Jonathan S. Austin Chengxi Zhang Amalia Patanè Walter Escoffier Michel Goiran Mathieu Pierre Camilla Coletti Vaidotas Mišeikis Lyudmila Turyanska Oleg Makarovsky 《Advanced Electronic Materials》2023,9(2):2200995
Stable all-inorganic CsPbX3 perovskite nanocrystals (PNCs) with high optical yield can be used in combination with graphene as photon sensors with high responsivity (up to 106 A W−1) in the VIS-UV range. The performance of these perovskite/graphene field effect transistors (FET) is mediated by charge transfer processes at the perovskite – graphene interface. Here, the effects of high electric (up to 3000 kV cm−1) and magnetic (up to 60 T) fields applied perpendicular to the graphene plane on the charge transfer are reported. The authors demonstrate electric- and magnetic-field dependent charge transfer and a slow (>100 s) charge dynamics. Magneto-transport experiments in constant (≈0.005 T s−1) and pulsed (≈1000 T s−1) magnetic fields reveal pronounced hysteresis effects in the transfer characteristics of the FET. A magnetic time is used to explain and model differences in device behavior under fast (pulsed) and slowly (continuous) changing magnetic fields. The understanding of the dynamics of the charge transfer in perovskite/graphene heterostructures developed here is relevant for exploitation of these hybrid systems in electronics and optoelectronics, including ultrasensitive photon detectors and FETs for metrology. 相似文献
4.
Intraband relaxation in all‐inorganic cesium lead tribromide (CsPbBr3) and hybrid organic–inorganic formamidinium lead tribromide (FAPbBr3) nanocrystals is experimentally investigated for a range of particle sizes, excitation energies, sample temperatures, and excitation fluences. Hot carriers in CsPbBr3 nanocrystals consistently exhibit slower cooling than FAPbBr3 nanocrystals in the single electron–hole pair per nanocrystal regime. In both compositions, long‐lived hot carriers (>3 ps) are only observed at excitation densities corresponding to production of multiple electron–hole pairs per nanocrystal—and concomitant Auger recombination. These presented results are distinct from previous reports in bulk hybrid perovskite materials that convey persistent hot carriers at low excitation fluences. Time‐resolved photoluminescence confirms the rapid cooling of carriers in the low‐fluence (single electron–hole pair per nanocrystal) regime. Intraband relaxation processes, as a function of excitation energy, size, and temperature are broadly consistent with other nanocrystalline semiconductor materials. 相似文献
5.
Man Zhao Fangxu Yang Chao Liang Dawei Wang Defang Ding Jiawei Lv Jianqi Zhang Wenping Hu Chenguang Lu Zhiyong Tang 《Advanced functional materials》2016,26(28):5182-5188
Coupling between colloidal semiconductor nanocrystals (NCs) with long‐range order is critical for designing advanced nanostructures with controlled energy flow and charge carrier transport. Herein, under the premise of keeping long‐range order in 2D NC monolayer, its native organic ligands are exchanged with halogen ions in situ at the liquid–air interface to enhance the coupling between NCs. Further treatments on the films with dimethyl sulfoxide, methanol, or their mixture effectively improve carrier mobility of the devices. The devices show repeatable enhanced p‐type transport behavior with hole mobility of up to 0.224 ± 0.069 cm2 V?1 s?1, the highest value reported for lead sulfide NC solids without annealing treatment. Thanks to accurate control over the surface of NCs as well as the structure of NC film, the ordered NC monolayer film of high hole mobility suggests great potentials for making reliable high performance devices. 相似文献
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Yinan Jiao Shenghui Yi Hanwen Wang Bing Li Weizhong Hao Lulu Pan Yan Shi Xiangyu Li Pengfei Liu He Zhang Cunfa Gao Jinjin Zhao Jian Lu 《Advanced functional materials》2021,31(4):2006243
The power conversion efficiencies (PCEs) of the solar cells containing metal halide perovskites (MHPs) have rapidly increased and exceeded 25% during the past decade. The photovoltaic properties of these devices are extensively investigated in terms of their microstructures, environmental characteristics, and carrier dynamics, and the MHP structural evolution under high pressure is evaluated. In addition, the energy level structure, electron/hole dynamics, and optical/electronic properties of MHPs with anisotropic crystal structures are examined. However, the correlation between the structural anisotropy and material properties of these perovskites is rarely considered in the literature studies on their high-pressure behavior. In this progress report, the optical/electronic properties of MHPs with anisotropic structures under thermal, mechanically imposed, and in-service strains/stresses that have been previously neglected by researchers are summarized. 相似文献
7.
Haiguang Zhao Ruijia Sun Zhaofen Wang Kaifang Fu Xun Hu Yuhai Zhang 《Advanced functional materials》2019,29(30)
Luminescent solar concentrators (LSCs) are able to efficiently harvest solar energy through large‐area photovoltaic windows, where fluorophores are delicately embedded. Among various types of fluorophores, all‐inorganic perovskite nanocrystals (NCs) are emerging candidates as absorbers/emitters in LSCs due to their size/composition/dimensionality tunable optical properties and high photoluminescence quantum yield (PL QY). However, due to the large overlap between absorption and emission spectra, it is still challenging to fabricate high‐efficiency LSCs. Intriguingly, zero‐dimensional (0D) perovskites provide a number of features that meet the requirements for a potential LSC absorber, including i) small absorption/emission spectral overlap (Stokes shift up to 1.5 eV); ii) high PL QY (>95% for bulk crystal); iii) robust stability as a result of its large exciton binding energy; and iv) ease of synthesis. In this work, as a proof‐of‐concept experiment, Cs4PbBr6 perovskite NCs are used to fabricate semi‐transparent large‐area LSCs. Cs4PbBr6 perovskite film exhibits green emission with a high PL QY of ≈58% and a small absorption/emission spectral overlap. The optimized LSCs exhibit an external optical efficiency of as high as 2.4% and a power conversion efficiency of 1.8% (100 cm2). These results indicate that 0D perovskite NCs are excellent candidates for high‐efficiency LSCs compared to 3D perovskite NCs. 相似文献
8.
Zhuxian Zhou Youqing Shen Jianbin Tang Maohong Fan Edward A Van Kirk William J Murdoch Maciej Radosz 《Advanced functional materials》2009,19(22):3580-3589
DNA‐toxin anticancer drugs target nuclear DNA or its associated enzymes to elicit their pharmaceutical effects, but cancer cells have not only membrane‐associated but also many intracellular drug‐resistance mechanisms that limit their nuclear localization. Thus, delivering such drugs directly to the nucleus would bypass the drug‐resistance barriers. The cationic polymer poly(L ‐lysine) (PLL) is capable of nuclear localization and may be used as a drug carrier for nuclear drug delivery, but its cationic charges make it toxic and cause problems in in‐vivo applications. Herein, PLL is used to demonstrate a pH‐triggered charge‐reversal carrier to solve this problem. PLL's primary amines are amidized as acid‐labile β‐carboxylic amides (PLL/amide). The negatively charged PLL/amide has a very low toxicity and low interaction with cells and, therefore, may be used in vivo. But once in cancer cells' acidic lysosomes, the acid‐labile amides hydrolyze into primary amines. The regenerated PLL escapes from the lysosomes and traverses into the nucleus. A cancer‐cell targeted nuclear‐localization polymer–drug conjugate has, thereby, been developed by introducing folic‐acid targeting groups and an anticancer drug camptothecin (CPT) to PLL/amide (FA‐PLL/amide‐CPT). The conjugate efficiently enters folate‐receptor overexpressing cancer cells and traverses to their nuclei. The CPT conjugated to the carrier by intracellular cleavable disulfide bonds shows much improved cytotoxicity. 相似文献
9.
Subodh K. Gautam Minjin Kim Douglas R. Miquita Jean‐Eric Boure Bernard Geffroy Olivier Plantevin 《Advanced functional materials》2020,30(28)
Mixed‐halide hybrid perovskite semiconductors have attracted tremendous attention as a promising candidate for efficient photovoltaic and light‐emitting devices. However, these perovskite materials may undergo phase segregation under light illumination, thus affecting their optoelectronic properties. Here, photoexcitation induced phase segregation in triple‐cation mixed‐halide perovskite films that yields to red‐shift in the photoluminescence response is reported. It is demonstrated that photoexcitation induced halide migration leads to the formation of smaller bandgap iodide‐rich and larger bandgap bromide‐rich domains in the perovskite film, where the phase segregation rate is found to follow the excitation power‐density as a power law. Results confirm that charge carrier lifetime increases due to the trapping of photoexcited carriers in the segregated smaller bandgap iodide‐rich domains. Interestingly, these photoinduced changes are fully reversible and thermally activated when the excitation power is turned off. A significant difference in activation energies for halide ion migration is observed during phase segregation and recovery process. Additionally, the emission linewidth broadening is investigated as a function of temperature which is governed by the exciton–optical phonon coupling. The mechanism of photoinduced phase segregation is interpreted based on exciton–phonon coupling strength in both mixed and demixed (segregated) states of perovskite films. 相似文献
10.
Asaf Kay Mor Fiegenbaum‐Raz Snke Müller Rainer Eichberger Hen Dotan Roel van de Krol Fatwa F. Abdi Avner Rothschild Dennis Friedrich Daniel A. Grave 《Advanced functional materials》2020,30(18)
The charge carrier dynamics of epitaxial hematite films is studied by time‐resolved microwave (TRMC) and time‐resolved terahertz conductivity (TRTC). After excitation with above bandgap illumination, the TRTC signal decays within 3 ps, consistent with previous reports of charge carrier localization times in hematite. The TRMC measurements probe charge carrier dynamics at longer timescales, exhibiting biexponential decay with characteristic time constants of ≈20–50 ns and 1–2 μs. From the change in photoconductance, the effective carrier mobility is extracted, defined as the product of the charge carrier mobility and photogeneration yield, of differently doped (undoped, Ti, Sn, Zn) hematite films for excitation wavelengths of 355 and 532 nm. It is shown that, unlike in conventional semiconductors, donor doping of hematite dramatically increases the effective mobility of the photogenerated carriers. Furthermore, it is shown that all hematite films possess higher effective mobility for 355 nm excitation than for 532 nm excitation, although the time dependence of the photoconductance decay, or charge carrier lifetime, remains the same. These results provide an explanation for the wavelength dependent photoelectrochemical behavior of hematite photoelectrodes and suggest that an increase in photogeneration yield or charge carrier mobility is responsible for the improved performance at higher excitation energies. 相似文献
11.
Shuaipeng Ge Xinwei Guan Yutao Wang Chun‐Ho Lin Yimin Cui Yunxia Huang Xinran Zhang Ruoxuan Zhang Xiaoting Yang Tom Wu 《Advanced functional materials》2020,30(25)
3D organic–inorganic and all‐inorganic lead halide perovskites have been intensively pursued for resistive switching memories in recent years. Unfortunately, instability and lead toxicity are two foremost challenges for their large‐scale commercial applications. Dimensional reduction and composition engineering are effective means to overcome these challenges. Herein, low‐dimensional inorganic lead‐free Cs3Bi2I9 and CsBi3I10 perovskite‐like films are exploited for resistive switching memory applications. Both devices demonstrate stable switching with ultrahigh on/off ratios (≈106), ultralow operation voltages (as low as 0.12 V), and self‐compliance characteristics. 0D Cs3Bi2I9‐based device shows better retention time and larger reset voltage than the 2D CsBi3I10‐based device. Multilevel resistive switching behavior is also observed by modulating the current compliance, contributing to the device tunability. The resistive switching mechanism is hinged on the formation and rupture of conductive filaments of halide vacancies in the perovskite films, which is correlated with the formation of AgIx layers at the electrode/perovskite interface. This study enriches the library of switching materials with all‐inorganic lead‐free halide perovskites and offers new insights on tuning the operation of solution‐processed memory devices. 相似文献
12.
Giuseppe M. Patern Nimai Mishra Alex J. Barker Zhiya Dang Guglielmo Lanzani Liberato Manna Annamaria Petrozza 《Advanced functional materials》2019,29(21)
Excitonic 0D and 2D lead‐halide perovskites have been recently developed and investigated as new materials for light generation. Here broadband (>1 eV) emission from newly synthesized 0D lead‐free colloidal Cs3Bi2I9 nanocrystals (NCs) is reported. The nature of their emissive states as well as the relative dynamics which are currently hotly debated are investigated. In particular, it is found that the broadband emission is made by the coexistence of emissive excitons and sub‐bandgap emissive trap‐states. Remarkably, evidence of enhanced Raman scattering from the ligands is observed when attached to the NCs surface, an effect that is preliminarily attributed to strong exciton‐ligands electronic coupling in these systems. 相似文献
13.
Mingfa Peng Yulong Ma Lei Zhang Shan Cong Xuekun Hong Yiheng Gu Yawei Kuang Yushen Liu Zhen Wen Xuhui Sun 《Advanced functional materials》2021,31(42):2105051
Perovskites have attracted intensive attention as promising materials for the application in various optoelectronic devices due to their large light absorption coefficient, high carrier mobility, and long charge carrier diffusion length. However, the performance of the pure perovskite nanocrystals-based device is extremely restricted by the limited charge transport capability due to the existence of a large number of the grain boundary between perovskite nanocrystals. To address these issues, a high-performance photodetector based on all-inorganic CsPbBr3 perovskite nanocrystals/2D non-layered cadmium sulfide selenide heterostructure has been demonstrated through energy band engineering with designed typed-II heterostructure. The photodetector exhibits an ultra-high light-to-dark current ratio of 1.36 × 105, a high responsivity of 2.89 × 102 A W−1, a large detectivity of 1.28 × 1014 Jones, and the response/recovery time of 0.53s/0.62 s. The enhancement of the optoelectronic performance of the heterostructure photodetector is mainly attributed to the efficient charge carrier transfer ability between the all-inorganic CsPbBr3 perovskites and 2D cadmium sulfide selenide resulting from energy band alignment engineering. The charge carriers’ transfer dynamics and the mechanism of the CsPbBr3 perovskites/2D non-layered nanosheets interfaces have also been studied by state-state PL spectra, fluorescence lifetime imaging microscopy, time-resolved photoluminescence spectroscopy, and Kelvin probe force microscopy measurements. 相似文献
14.
Waner He Wenchao Xu Huixin He Xiaosai Jing Chuan Liu Jiajun Feng Chunlai Luo Zhen Fan Sujuan Wu Jinwei Gao Guofu Zhou Xubing Lu Junming Liu 《Advanced Electronic Materials》2020,6(4)
Write‐once‐read‐many (WORM) memory behavior is often observed in polymer electret memory (PEM) devices, greatly limiting their overall performance. This paper systematically investigates the device physics of PEM devices with poly(α‐methylstyrene) as a charge trapping layer and pentacene as a semiconductor channel. The combined experiments on transistors, capacitances, and optical spectroscopy reveal that both the WORM memory behavior after negative and positive pulses and the gradual formation of memory after the continuous scanning are the results of the deficiency in minority (electrons) transport and trapping. Corresponding quantitative models are established and well explain the two‐stage, gradual trapping processes to form memory. By reducing the structural disorder and lateral channel length, ambipolar, bistable memory and much faster formation of memory window is obtained based on the same PEM device. The insights into device physics of PEM devices are expected to facilitate the design of organic, nonvolatile memory devices with high programming and erasing efficiencies. 相似文献
15.
Artem Musiienko Davide Raffaele Ceratti Jindřich Pipek Mykola Brynza Hassan Elhadidy Eduard Belas Marián Betušiak Geraud Delport Petr Praus 《Advanced functional materials》2021,31(48):2104467
The interaction of free carriers with defects and some critical defect properties are still unclear in methylammonium lead halide perovskites (MHPs). Here, a multi-method approach is used to quantify and characterize defects in single crystal MAPbI3, giving a cross-checked overview of their properties. Time of flight current waveform spectroscopy reveals the interaction of carriers with five shallow and deep defects. Photo-Hall and thermoelectric effect spectroscopy assess the defect density, cross-section, and relative (to the valence band) energy. The detailed reconstruction of free carrier relaxation through Monte Carlo simulation allows for quantifying the lifetime, mobility, and diffusion length of holes and electrons separately. Here, it is demonstrated that the dominant part of defects releases free carriers after trapping; this happens without non-radiative recombination with consequent positive effects on the photoconversion and charge transport properties. On the other hand, shallow traps decrease drift mobility sensibly. The results are the key for the optimization of the charge transport properties and defects in MHP and contribute to the research aiming to improve perovskite stability. This study paves the way for doping and defect control, enhancing the scalability of perovskite devices with large diffusion lengths and lifetimes. 相似文献
16.
Blue light emitting two dimensional (2D) and quasi‐2D layered halide perovskites (LHPs) are gaining attention in solid‐state lighting applications but their fragile stability in humid condition is one of the most pressing issues for their practical applications. Though water is much greener and cost effective, organic solvents must be used during synthesis as well as the device fabrication process for these LHPs due to their water‐sensitivity/instability and consequently, water‐stable blue‐light emitting 2D and quasi‐2D LHPs have not been documented yet. Here, water‐mediated facile and cost‐effective syntheses, characterizations, and optical properties of 16 organic–inorganic hybrid compounds are reported including 2D (A′)2PbX4 (A′ = butylammonium, X = Cl/Br/I) (8 compounds), 3D perovskites (4), and quasi‐2D (A′)pAx?1BxX3x+1 LHPs (A = methylammonium) (4) in water. Here, both composition and dimension of LHPs are tuned in water, which has never been explored yet. Furthermore, the dual emissive nature is observed in quasi‐2D perovskites, where the intensity of two photoluminescence (PL) peaks are governed by 2D and 3D inorganic layers. The Pb(OH)2‐coated 2D and quasi‐2D perovskites are highly stable in water even after several months. In addition, single particle imaging is performed to correlate structural–optical property of these LHPs. 相似文献
17.
Anurag Krishna Sbastien Gottis Mohammad Khaja Nazeeruddin Frdric Sauvage 《Advanced functional materials》2019,29(8)
The cost‐effective processability and high efficiency of the organic–inorganic metal halide perovskite solar cells (PSCs) have shown tremendous potential to intervene positively in the generation of clean energy. However, prior to an industrial scale‐up process, there are certain critical issues such as the lack of stability against over moisture, light, and heat, which have to be resolved. One of the several proposed strategies to improve the stability that has lately emerged is the development of lower‐dimensional (2D) perovskite structures derived from the Ruddlesden–Popper (RP) phases. The excellent stability under ambient conditions shown by 2D RP phase perovskites has made the scalability expectations burgeon since it is one of the most credible paths toward stable PSCs. In this review, the 2D/3D mixed system for photovoltaics (PVs) is elaborately discussed with the focus on the crystal structure, optoelectronic properties, charge carrier dynamics, and their impact on the photovoltaic performances. Finally, some of the further challenges are highlighted while outlining the perspectives of 2D/3D perovskites for high‐efficiency stable solar cells. 相似文献
18.
Masahiro Minagawa Kazunari Shinbo Keizo Kato Futao Kaneko 《Electronics and Communications in Japan》2009,92(3):24-31
Organic electroluminescent device (OLED) was fabricated using a vacuum evaporation method and thermal properties were investigated. The OLED has an indium tin oxide (ITO)/N,N′‐diphenyl‐N,N′‐bis(3‐methylphenyl)‐1,1′‐biphenyl‐4,4′‐diamine (TPD)/tris(8‐hydroxyquinoline) aluminum (Alq)/lithium fluoride (LiF)/aluminum (Al) structure. An electron‐dominant device of Al/Alq/LiF/Al structure, or a hole‐dominant device of ITO/TPD/Al structure was also fabricated in order to study the carrier behavior in the OLEDs. The current density versus voltage (J–V) properties with various thickness of organic layers were investigated in both electron‐ and hole‐dominant devices, and the thermal dependence of J–V properties was observed in the devices. At room temperature, conductions in a wide current region were considered to be due to space‐charge‐limited current for all of the devices. Especially for the Al/Alq/LiF/Al device and the OLED, relationships were observed across a wide current region. At low temperature, tunnel currents were estimated for the ITO/TPD/Al device. For the Al/Alq/LiF/Al device and the OLED, relationships were observed across a wide current region at low temperature. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 92(3): 24–31, 2009; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/ecj.10048 相似文献
19.
Zhi Fang Xinmei Hou Yapeng Zheng Zuobao Yang Kuo-Chih Chou Gang Shao Minghui Shang Weiyou Yang Tom Wu 《Advanced functional materials》2021,31(28):2102330
Quasi-2D CsPbI3 perovskites have emerged as excellent candidates for advanced photovoltaic technologies due to their fundamentally enhanced stability than conventional 3D counterparts. However, the applications of quasi-2D perovskites are plagued with their poor out-of-plane carrier mobility induced by the intercalated insulating organic layers. In this work, a new strategy is explored to significantly enhance the out-of-plane charge transport in quasi-2D Dion–Jacobson (DJ) CsPbI3 perovskites via leveraging the intercalation of aromatic diamine cations (p-phenylenediamine, PPDA) with unique π-conjugated bond based on the first-principles calculations. The strong interactions between PPDA2+ cations and inorganic Pb-I framework (i.e., I–I interaction, p-π coupling, and H-bonds) provide three carrier pathways to facilitate the out-of-plane charge transport. Furthermore, the restricted in-plane and out-of-plane structural distortion induced by the π-conjugated bond could improve the electronic coupling and charge mobility along the out-of-plane direction with reduced bandgaps. As a proof of concept, the calculated average photovoltaic conversion efficiency of such engineered DJ CsPbI3 perovskite solar cells is ≈17%, which is very close to the certificated champion efficiency of 3D α-CsPbI3, underscoring their potential for solar cell applications. 相似文献
20.
Chee Chin Tan Vincent K. S. Ong K. Radhakrishnan 《Progress in Photovoltaics: Research and Applications》2013,21(5):986-995
Charge collection is one of the crucial processes to collect the induced current when a semiconductor sample is subjected to some external excitations such as the electron or photon beams. The charge collection probability is the basis in the study of this induced current particularly in the field of photonic devices, photovoltaic cells as well as in the characterization of semiconductor materials and devices. In this paper, the analytical expressions for the charge collection probability of the finite‐dimension normal‐collector configuration, with and without surface recombination at the free surfaces are presented. An excellent agreement has been found between the charge collection probability profiles computed using the presently derived analytical expressions and those obtained using a device simulator. The results have been used to study the effects of the various physical parameters on the charge collection probability. These analytical expressions are expected to enhance our understanding of the charge collection process. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献