N‐doped carbon nanomaterials have rapidly grown as the most important metal‐free catalysts in a wide range of chemical and electrochemical reactions. This current report summarizes the latest ...advances in N‐doped carbon electrocatalysts prepared by N mono‐doping and co‐doping with other heteroatoms. The structure–performance relationship of these materials is subsequently rationalized and perspectives on developing more efficient and sustainable electrocatalysts from carbon nanomaterials are also suggested.
N‐doped carbon nanomaterials have recently emerged as the most important metal‐free catalysts in electrochemical catalysis. The latest advances in N‐doped carbon electrocatalysts prepared by N mono‐doping and co‐doping with other heteroatoms are summarized and the structure−performance relationship of these materials is rationalized. Perspectives on developing more efficient and sustainable electrocatalysts from carbon nanomaterials are also suggested.
Nanostructured polyaniline (PANI) counter electrodes (CEs) with different doping levels have been fabricated using in-situ electrochemical polymerization under different doping H sub(2)SO sub(4) ...concentration for applications in dye-sensitized solar cells (DSSCs). The effects of the H sub(2)SO sub(4) concentration on properties of the obtained PANI CEs, such as morphology, degree of polymerization, doping level of the SO super(2) sub(4) super(-) counter anions, oxidization state, and electrochemical activity for I super(-) sub(3) reduction, are thoroughly investigated using different techniques, such as scanning electron microscope (SEM), ultraviolet-visible light spectroscopy (UV-vis). X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). When using D149 dye-sensitized nanocrystalline TiO sub(2) photoanode, DSSC based on PANI CE polymerized with 0.35 M H sub(2)SO sub(4) shows the best photovoltaic performance with a solar-to-energy conversion efficiency up to 5.57%, which is competitive to that of Pt CE-based solar cells (6.00%). This is because PANI CE polymerized under such conditions exhibits high catalytic activity for I super(-)/I super(-) sub(3) redox reaction because of the large surface area, high degree of polymerization/oriented structure, high doping level, and high emeraldine base oxidization state. Thus, our results can help to prepare the PANI CEs with a better DSSC performance and, more important, to better understand the operation mechanism of PANI CEs.
Polycrystalline samples of Ca3ax Bi x Co4O9+I' (x = 0.00, 0.05, 0.10, 0.15, 0.20 and 0.30) have been prepared by conventional solid-state synthesis. Thermopower of all the samples is positive, ...indicating that the predominant carriers are holes over the entire temperature range. The resistivity of all the samples, except the one with x = 0.30, exhibits nonmetal to metal transition (T MI) in the low temperature regime. The resistivity results indicate that all the doped samples obey the variable range hopping in the low temperature regime. The T MI and T * (transition temperature from Fermi liquid metal to incoherent metal) increase, and the slope of A value (Fermi-liquid transport coefficient) decreases with the increasing Bi content due to an increase in chemical pressure in the lattice. Among the samples, Ca2.7Bi0.3Co4O9+I' has the highest dimensionless figure of merit of 0.091 at 300 K. This value represents an improvement of about 135 % compared to the undoped Ca3Co4O9+I' . Magnetic measurements indicate that all the samples exhibit a low-spin state of cobalt ion. The ferrimagnetic transition temperature is suppressed by the Bi dopant. These results suggest that Bi is an effective doping element for improving the thermoelectric properties of Ca3Co4O9+I' .
This unique international legal and cross-disciplinary edited volume contains analysis of the legal impact of doping regulation by eminent and well known experts in the legal fields of sports doping ...regulation and diverse legal fields which are intrinsically important areas for consideration in the sports doping landscape. These are thoughtful extended reflections by experts on theory and policy and how they interact with law in the context of doping in sport. It is the first book to examine the topical and contentious area of sports doping from a variety of different but very relevant legal perspectives which impact the stakeholders in sport at both professional and grass roots levels. The World Anti-Doping Code contains an unusual mix of public and private regulation which is of more general interest and fully explored in this work. Each of the 14 chapters addresses doping regulation from a legal perspective such as tort, corporate governance, employment law, human rights law, or a scientific area. Legal areas are generally considered from an international and not national perspective. Issues including fairness, logic and the likelihood of compliance are explored. It is vital reading for anyone interested in the law, regulation and governance of sport.
Molecular doping is a crucial tool for controlling the charge-carrier concentration in organic semiconductors. Each dopant molecule is commonly thought to give rise to only one polaron, leading to a ...maximum of one donor:acceptor charge-transfer complex and hence an ionization efficiency of 100%. However, this theoretical limit is rarely achieved because of incomplete charge transfer and the presence of unreacted dopant. Here, we establish that common p-dopants can in fact accept two electrons per molecule from conjugated polymers with a low ionization energy. Each dopant molecule participates in two charge-transfer events, leading to the formation of dopant dianions and an ionization efficiency of up to 200%. Furthermore, we show that the resulting integer charge-transfer complex can dissociate with an efficiency of up to 170%. The concept of double doping introduced here may allow the dopant fraction required to optimize charge conduction to be halved.
Solution‐processable highly conductive polymers are of great interest in emerging electronic applications. For p‐doped polymers, conductivities as high a nearly 105 S cm−1 have been reported. In the ...case of n‐doped polymers, they often fall well short of the high values noted above, which might be achievable, if much higher charge‐carrier mobilities determined could be realized in combination with high charge‐carrier densities. This is in part due to inefficient doping and dopant ions disturbing the ordering of polymers, limiting efficient charge transport and ultimately the achievable conductivities. Here, n‐doped polymers that achieve a high conductivity of more than 90 S cm−1 by a simple solution‐based co‐deposition method are reported. Two conjugated polymers with rigid planar backbones, but with disordered crystalline structures, exhibit surprising structural tolerance to, and excellent miscibility with, commonly used n‐dopants. These properties allow both high concentrations and high mobility of the charge carriers to be realized simultaneously in n‐doped polymers, resulting in excellent electrical conductivity and thermoelectric performance.
Two conjugated polymers with rigid planar backbones, but with disordered crystalline structures, exhibit surprising structural tolerance to commonly used n‐dopants. These properties allow both high concentrations and high mobility of the charge carriers to be realized simultaneously in n‐doped polymers, resulting in excellent electrical conductivity of over 90 S cm−1 and thermoelectric performance up to 106 µW m−1 K−2.
In this contribution, for the first time, the molecular n‐doping of a donor–acceptor (D–A) copolymer achieving 200‐fold enhancement of electrical conductivity by rationally tailoring the side chains ...without changing its D–A backbone is successfully improved. Instead of the traditional alkyl side chains for poly{N,N′‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl(NDI)‐alt‐5,5′‐(2,2′‐bithiophene)} (N2200), polar triethylene glycol type side chains is utilized and a high electrical conductivity of 0.17 S cm−1 after doping with (4‐(1,3‐dimethyl‐2,3‐dihydro‐1H‐benzoimidazol‐2‐yl)phenyl)dimethylamine is achieved, which is the highest reported value for n‐type D–A copolymers. Coarse‐grained molecular dynamics simulations indicate that the polar side chains can significantly reduce the clustering of dopant molecules and favor the dispersion of the dopant in the host matrix as compared to the traditional alkyl side chains. Accordingly, intimate contact between the host and dopant molecules in the NDI‐based copolymer with polar side chains facilitates molecular doping with increased doping efficiency and electrical conductivity. For the first time, a heterogeneous thermoelectric transport model for such a material is proposed, that is the percolation of charge carriers from conducting ordered regions through poorly conductive disordered regions, which provides pointers for further increase in the themoelectric properties of n‐type D–A copolymers.
Significantly enhanced molecularly doping of an n‐type donor–acceptor (D–A) copolymer by rationally tailoring its side chains without changing its donor–acceptor character is demonstrated. Polar triethylene‐glycol‐based side chains on the host greatly increase the solubility of dopant molecules in the host matrix with respect to the traditional alkyl side chains. The former gives a highest conductivity of 0.17 S cm−1 for D–A copolymers, representing a 200‐fold enhancement compared to the latter.
Undoped and Zn-doped SnO sub(2) thin films are deposited onto glass substrates by sol-gel spin coating method. All the films are characterized by X-ray photon spectroscopy (XPS) and Fourier transform ...infra-red spectroscopy (FTIR). XPS shows that Sn presence as valence of Sn super(4+) in the prepared SnO sub(2) thin films instead of Sn super(2+). In addition, it also exhibits the amount of Zn in SnO sub(2) thin films, which increases with increasing Zn doping percentage. The Zn (2P sub(3/2)) peak is symmetric and centred at around 1,021.73 eV which shifts to the lower binding energy of 1,020.83 eV for 15 at.% Zn doped SnO sub(2) thin film. FTIR study is used to describe the local environment of undoped and Zn-doped SnO sub(2) thin films which also confirms the synthesis of undoped and Zn-doped SnO sub(2) thin films. It is found that the resistance of SnO sub(2) thin films increases as Zn doping concentration increases at room humidity. The resistance of all the samples increases as relative humidity (RH) increases. The sensitivity of SnO sub(2) thin films increases as RH increases while it decreases as Zn doping percentage increases. Response time of SnO sub(2) thin film decreases as Zn doping percentage increases and recovery time slightly increases with doping percentage.
Owing to their excellent physical properties, atomically thin layers of molybdenum disulfide (MoS2) have recently attracted much attention due to their nonzero‐gap property, exceptionally high ...electrical conductivity, good thermal stability, and excellent mechanical strength, etc. MoS2‐based devices exhibit great potential for applications in optoelectronics and energy harvesting. Here, a comprehensive review of various doping strategies is presented, including wet doping and dry doping of atomically crystalline MoS2 thin layers, and the progress made so far for their doping‐based prospective applications is also discussed. Finally, several significant research issues for the prospects of doped‐MoS2 in industry, as a guide for 2D material community, are also provided.
Various strategies for doping of molybdenum disulfide are comprehensively reviewed, including wet doping and dry doping of MoS2 thin layers and the progress made so far for their doping‐based industrial applications. Finally, a few important opening study directions for future prospects of doped atomically crystalline MoS2 layers in optoelectronics and energy harvesting, as a guide for the 2D material community, are also provided.
Selective doping of a single conjugated polymer (CP) to obtain p‐type and n‐type conductive materials would be highly attractive for organic thermoelectric applications, because it will greatly ...reduce the time and costs of synthesizing different types of CPs. However, this strategy has rarely been investigated. In this study, two CPs are synthesized, designated PTQDPP‐T and PTQDPP‐2FT, based on a newly developed quinoidal unit with thienoisatin as the termini and a thiophene‐flanked diketopyrrolopyrrole (ThDPP) unit as the quinoidal core. The electron‐rich thiophene rings in thienoisatin and the electron delocalization induced by thienoisatin resulted in polymers with high‐lying highest occupied molecular orbital, and the electron‐deficient nature of ThDPP unit and its quinoidal backbone endowed the polymers with low‐lying lowest unoccupied molecular orbitals. As a result, both polymers can be p‐type and n‐type doped. Because of its high mobility, doped PTQDPP‐2FT performed better in organic thermoelectric devices than the doped PTQDPP‐T. After being doped with FeCl3 and N‐DMBI, PTQDPP‐2FT showed p‐type and n‐type power factors of 278.2 and 2.37 µW m−1 K−2, respectively. These are the best for bipolar (p‐type and n‐type) performances that obtained by selective doping of a single polymer.
Polymers that can be both p‐doped and n‐doped are synthesized via incorporating a thienoisatin terminated quinoidal unit. Organic thermoelectric devices with a p‐type power factor >270 µW m−1 K−2 and an n‐type power factor >2 µW m−1 K−1 are fabricated by selective doping the polymers with FeCl3 and N‐DMBI, respectively.
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