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Multi-scale ordering in highly stretchable polymer semiconducting films
摘要： Stretchable semiconducting polymers have been developed as a key component to enable skin-like wearable electronics, but their electrical performance must be improved to enable more advanced functionalities. Here, we report a solution processing approach that can achieve multi-scale ordering and alignment of conjugated polymers in stretchable semiconductors to substantially improve their charge carrier mobility. Using solution shearing with a patterned microtrench coating blade, macroscale alignment of conjugated-polymer nanostructures was achieved along the charge transport direction. In conjunction, the nanoscale spatial confinement aligns chain conformation and promotes short-range π–π ordering, substantially reducing the energetic barrier for charge carrier transport. As a result, the mobilities of stretchable conjugated-polymer films have been enhanced up to threefold and maintained under a strain up to 100%. This method may also serve as the basis for large-area manufacturing of stretchable semiconducting films, as demonstrated by the roll-to-roll coating of metre-scale films.
关键词： charge carrier mobility,conjugated polymers,solution shearing,stretchable semiconductors,roll-to-roll coating,multi-scale ordering
更新于2025-11-19 16:56:35
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Admittance of Organic LED Structures with an Emission YAK-203 Layer
摘要： The current-voltage characteristics and admittance of multilayer structures for organic LEDs based on the PEDOT:PSS/NPD/YAK-203/BCP system have been experimentally investigated in a wide range of the measurement conditions. It is shown that at voltages corresponding to the effective radiative recombination of charge carriers, a significant decrease in the differential capacitance of the structures is observed. The frequency dependences of the normalized conductance of LED structures are in good agreement with the results of numerical simulation in the framework of the equivalent circuit method. Changes in the frequency dependences of the admittance with a change in temperature are most pronounced in the temperature range of 200–300 K and less noticeable in the temperature range of 8–200 K. From the frequency dependences of the imaginary part of impedance, the charge carrier mobilities are found at various voltages and temperatures. The mobility values obtained by this method are somewhat lower than those determined by the transient electroluminescence method. The dependence of the mobility on the electric field is well approximated by a linear function. As the temperature decreases from 300 to 220 K, the mobility decreases several times.
关键词： frequency dependence of imaginary part of impedance,LED structure,current-voltage characteristic,transient electroluminescence,organic semiconductor,charge carrier mobility,method of equivalent circuits,admittance
更新于2025-11-14 17:28:48
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[IEEE 2018 IEEE International Conference on Electron Devices and Solid State Circuits (EDSSC) - Shenzhen (2018.6.6-2018.6.8)] 2018 IEEE International Conference on Electron Devices and Solid State Circuits (EDSSC) - Analysis of 1/f Noise for Organic TFTs Considering Mobility Power-Law Parameter
摘要： Based on carrier number fluctuation model, 1/f noise is analyzed for organic thin-film transistors (TFTs) at low drain voltage. The carrier mobility is gate-voltage-dependent, and is described by a power-law function. The mobility power-law parameter α determines the relationship between drain current noise power spectral density (PSD) SIDS and drain current IDS, and it is found that SIDS /I 2 DS when α = 1. It is different from the well-known rule for the MOSFETs with the constant carrier mobility: When SIDS /I 2 DS , Hooge’s mobility fluctuation model dominates the 1/f noise.
关键词： carrier mobility,Thin-film transistor (TFT),analytical model,low frequency noise
更新于2025-09-23 15:23:52
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First-principles study of the surface reparation of ultrathin InSe with Se-atom vacancies by thiol chemistry
摘要： Utilizing first-principles calculations, the surface reparation of monolayer InSe with Se-atom vacancies by thiol chemistry was studied. The geometrical structures and electronic properties of monolayer InSe with Se-atom vacancies were evaluated before and after reparation by S atoms, benchmarked against defect-free case. The parameters of bond lengths, band gaps and carrier mobilities can be recovered to the standard of pristinely defect-free structure. Moreover, the interaction of S atom with complete part of monolayer InSe was also investigated. S atom cannot adsorb on the surface without Se-atom vacancies, while it can substitute Se atom or insert into the interior of monolayer InSe. And the insertion was able to induce a decrease by one order of magnitude. It was demonstrated that thiol chemistry was an effective method to repair Se-atom vacancies and maintain its oxidation resistance, while the insertion of S atom into the interior of monolayer InSe should be avoided.
关键词： Indium selenides,Carrier mobility,Se-atom vacancies,Band gap,First-principles
更新于2025-09-23 15:22:29
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Strain-Engineered Ultrahigh Mobility in Phosphorene for Terahertz Transistors
摘要： Carrier mobility is a key parameter for the operation of electronic devices as it determines the ON state current and switching speed/frequency response of transistors. 2D phosphorene is considered as a potential candidate for field-effect transistors due to its high mobility. Here it is proposed to further enhance the carrier mobility of phosphorene and device performance via strain engineering. A systematic ab initio investigation on the anisotropic electronic structure of few-layer phosphorene reveals that the monolayer under 7.5–10% strain along zigzag direction shows an exceptional carrier mobility of ≈106 cm2 V?1 s?1, which is 10 times higher than the strain-free case. The simulated device performance shows that strain-engineered phosphorene–based field-effect transistors demonstrate a cut-off frequency of ≈1.14 THz with a gate length of 1.0 micron and 112 THz with a sub-10 nm gate length.
关键词： carrier mobility,density functional theory,phosphorene,transistors,strain-engineered electronics
更新于2025-09-23 15:22:29
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Carbon nanotubes assisting interchain charge transport in semiconducting polymer thin films towards much improved charge carrier mobility; 碳纳米管辅助共轭聚合物薄膜链间载流子传输以提高迁移率;
摘要： Conjugated polymers attracted much attention in the past few decades due to their wide applications in various optoelectronic devices and circuits. The charge transport process in conjugated polymers mainly occurs in the intrachain and interchain parts, where the interchain charge transport is generally slower than intrachain transport and may slow down the whole charge transport properties. Aiming at this issue, herein we employ semiconducting single-walled carbon nanotubes (s-SWNTs) as efficient charge-transporting jointing channels between conjugated polymer chains for improving the charge transport performance. Taking the typical conjugated polymer, ploy-N-alkyl-diketopyrrolo-pyrrole-dithienylthieno[3,2-b]thiophene (PDPP-TT) as an example, polymer thin film transistors (PTFTs) based on the optimized blended films of PDPP-TT/s-SWNTs exhibit an obviously increasing device performance compared with the devices based on pure PDPP-TT films, with the hole and electron mobility increased from 2.32 to 12.32 cm2 V?1 s?1 and from 2.02 to 5.77 cm2 V?1 s?1, respectively. This result suggests the importance of forming continuous conducting channels in conjugated polymer thin films, which can also be extended to other polymeric electronic and optoelectronic devices to promote their potential applications in large-area, low-cost and high performance polymeric electronic devices and circuits.
关键词： connected conducting channel,conjugated polymer,s-SWNTs,carrier mobility
更新于2025-09-23 15:22:29
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Synergistic Cascade Carrier Extraction via Dual Interfacial Positioning of Ambipolar Black Phosphorene for Higha??Efficiency Perovskite Solar Cells
摘要： 2D black phosphorene (BP) carries a stellar set of physical properties such as conveniently tunable bandgap and extremely high ambipolar carrier mobility for optoelectronic devices. Herein, the judicious design and positioning of BP with tailored thickness as dual-functional nanomaterials to concurrently enhance carrier extraction at both electron transport layer/perovskite and perovskite/hole transport layer interfaces for high-efficiency and stable perovskite solar cells is reported. The synergy of favorable band energy alignment and concerted cascade interfacial carrier extraction, rendered by concurrent positioning of BP, delivered a progressively enhanced power conversion efficiency of 19.83% from 16.95% (BP-free). Investigation into interfacial engineering further reveals enhanced light absorption and reduced trap density for improved photovoltaic performance with BP incorporation. This work demonstrates the appealing characteristic of rational implementation of BP as dual-functional transport material for a diversity of optoelectronic devices, including photodetectors, sensors, light-emitting diodes, etc.
关键词： ambipolar carrier mobility,cascade interfacial carrier extraction,black phosphorene,perovskite solar cells,band energy alignment
更新于2025-09-23 15:21:01
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Tweaking the physics of interfaces between monolayers of buckled cadmium sulfide for a superhigh piezoelectricity, excitonic solar cell efficiency and thermoelectricity
摘要： Interfaces of heterostructures are routinely studied for different applications. Interestingly, monolayers of the same material when interfaced in an unconventional manner can bring about novel properties. For instance, CdS monolayers, stacked in a particular order, are found to show unprecedented potential in the conversion of nanomechanical energy, solar energy and waste heat into electricity, which has been systematically investigated in this work, using DFT based approaches. Moreover, stable ultrathin structures showing strong capabilities for all kinds of energy conversion are scarce. The emergence of a very high out-of-plane piezoelectricity, |d33| ~ 56 pm/V, induced by the inversion symmetry broken in the buckled structure helps to supersede the previously reported bulk wurzite GaN, AlN and Janus multilayer structures of Mo and W based dichalcogenides. The piezoelectric coefficients have been found to be largely dependent on the relative stacking between the two layers. CdS bilayer is a direct band gap semiconductor with its band edges straddling the water redox potential, thereby making it thermodynamically favorable for photocatalytic applications. Strain engineering facilitates its transition from type-I to type-II semiconductor in CdS bilayer stacked over monolayer boron phosphide, and the theoretically calculated power conversion efficiency (PCE) in the 2D excitonic solar cell exceeds 27% for a fill factor of 0.8, which is much higher than that in ZnO/CdS/CuInGaSe solar cell (20% efficiency). Thermoelectric properties have been investigated using semi classical Boltzmann transport equations for electrons and phonons within the constant relaxation time approximation coupled to deformation potential theory, which reveal ultralow thermal conductivity (~ 0.78 Wm-1K-1) at room temperature due to the presence of heavy element Cd, strong anharmonicity (high mode Gruneisen parameter at long wavelength, phonon lifetime < 5 ps), low phonon group velocity (4 km/s) and low Debye temperature (260 K). Such a low thermal conductivity is lower than that of dumbbell silicene (2.86 Wm-1K-1), SnS2 (6.41 Wm-1K-1) and SnSe2 (3.82 Wm-1K-1), SnP3 (4.97 Wm-1K-1). CdS bilayer shows a thermoelectric figure of merit (ZT) ~ 0.8 for p-type and ~ 0.7 for n-type doping at room temperature. Its ultrahigh carrier mobility (μe ~2270 cm2V-1s-1) is higher than that of single layer MoS2 and comparable to that in InSe. The versatile properties of CdS bilayer together with its all-round stability supported by ab initio molecular dynamics simulation, phonon dispersion and satisfaction of Born-Huang stability criteria highlight its outstanding potential for applications in device fabrication and applications in next generation nanoelectronics and energy harvesting.
关键词： Power conversion efficiency,Excitonic solar cell,Piezoelectricity,Photocatalysis,Solar energy,Semiconductor,Thermoelectricity,Carrier mobility
更新于2025-09-23 15:21:01
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Non-fullerene small molecule acceptors with three-dimensional thiophene/selenophene-annulated perylene diimides for efficient organic solar cells
摘要： Three-dimensional non-fullerene acceptors with a spiro core linked with S/Se fused perylene diimides possess appropriate energy levels, twisted molecular configuration and high carrier mobility, leading to a power conversion efficiency of 6.95% for the organic solar cells.
关键词： perylene diimides,organic solar cells,carrier mobility,non-fullerene acceptors,spiro core
更新于2025-09-23 15:21:01
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Potential and limitations of CsBi3I10 as photovoltaic material
摘要： Herein we demonstrate the dry synthesis of CsBi3I10 both as free-standing material as well as in the form of homogeneous thin films, deposited by thermal vacuum deposition. Chemical and optical characterization shows high thermal stability, phase purity, and photoluminescence centered at 700 nm, corresponding to a bandgap of 1.77 eV. These characteristics make CsBi3I10 a promising low-toxicity material for wide bandgap photovoltaics. Nevertheless, the performance of this material as a semiconductor in solar cells remains rather limited, which can be at least partially ascribed to a low charge carrier mobility, as determined from pulsed-radiolysis, time-resolved microwave conductivity. Further developments should focus on understanding and overcoming the current limitations in charge mobility, possibly by compositional tuning through doping and/or alloying, as well as optimizing thin film morphology which may be another limiting factor.
关键词： photovoltaic material,thermal vacuum deposition,CsBi3I10,dry synthesis,charge carrier mobility
更新于2025-09-23 15:21:01