Concentration Dependent Mobility Research Articles

Differential MRGPRX2-dependent activation of human mast cells by polymyxins and octapeptins

The emergence of multi-drug resistant Gram-negative bacteria has led to renewed interest in the antimicrobial activity of polymyxins and novel polymyxin analogues (e.g. nonapeptides and octapeptin). In some individuals, clinically used polymyxins can cause acute hypersensitivity reactions through mast cell activation, with a recent study attributing this effect to activation of the MAS-related G protein-coupled receptor X2 (MRGPRX2). In the present study, HEK293 cells expressing human MRGPRX2 and the human mast cell line LAD2 were used to characterize the activity of the broader family of polymyxins. Octapeptin C4, polymyxin B and colistin produced concentration-dependent calcium mobilization, degranulation, and CCL-2 (MCP-1) release in LAD2 mast cells, with the former being highly potent. CRISPR-Cas9 knockdown of MRGPRX2 in LAD2 cells and a MRGPRX2 inverse agonist caused a significant reduction in calcium mobilization, degranulation, and CCL-2 release, demonstrating dependency on MRGPRX2 expression. In contrast, polymyxin nonapeptides were far less potent calcium mobilisers and failed to induce functional degranulation in LAD2 cells. Our results confirm that activation of mast cells induced by polymyxin-related antibiotics is MRGPRX2-dependent and reveal that octapeptin C4 might be more liable, whilst nonapeptides are less liable, to trigger immediate hypersensitivity reactions clinically. The mechanism underpinning the difference in MRGPRX2 activation between polymyxin-related antibiotics is important to better understand as it may help design new, safer polymyxins and guide the optimal clinical use of existing polymyxin drugs.

A second-order fully-balanced structure-preserving variational discretization scheme for the Cahn–Hilliard–Navier–Stokes system

We propose and analyze a structure-preserving space-time variational discretization method for the Cahn–Hilliard–Navier–Stokes system. Uniqueness and stability for the discrete problem is established in the presence of concentration-dependent mobility and viscosity parameters by means of the relative energy estimates and order optimal convergence rates are established for all variables using balanced approximation spaces and relaxed regularity conditions on the solution. Numerical tests are presented to demonstrate the proposed method is fully practical and yields the predicted convergence rates. The discrete stability estimates developed in this paper may also be used to analyse other discretization schemes, which is briefly outlined in the discussion.

Stability and discretization error analysis for the Cahn–Hilliard system via relative energy estimates

The stability of solutions to the Cahn–Hilliard equation with concentration dependent mobility with respect to perturbations is studied by means of relative energy estimates. As a by-product of this analysis, a weak-strong uniqueness principle is derived on the continuous level under realistic regularity assumptions on strong solutions. The stability estimates are further inherited almost verbatim by appropriate Galerkin approximations in space and time. This allows to derive sharp bounds for the discretization error in terms of certain projection errors and to establish order-optimal a priori error estimates for semi- and fully discrete approximation schemes. Numerical tests are presented for illustration of the theoretical results.

Cryogenic Characteristics of InGaAs MOSFET

We present an investigation of the temperature dependence of the current characteristic of a long-channel InGaAs quantum well MOSFET. A model is developed, which includes the effects of band tail states, electron concentration-dependent mobility, and interface trap density to accurately explain the measured data over all modes of operation. The increased effect of remote impurity scattering is associated with mobility degradation in the subthreshold region. The device has been characterized down to 13 K, with a minimum inverse subthreshold slope of 8 mV/dec and a maximum ON-state mobility of 6700 cm2/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}\cdot \text{s}$ </tex-math></inline-formula> and with values of 75 mV/dec and 3000 cm2/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\text{V}\cdot \text{s}$ </tex-math></inline-formula> at room temperature.

CALPHAD integrated grain boundary co-segregation design: Towards safe high-entropy alloys

Along with the desire for developing novel multi-principal element alloys, also known as high-entropy alloys, the concern about their safe application is also increasingly growing. This relates to the alloys’ phase stability, in particular, the control required over unexpected phase decompositions resulting from solute segregation at grain boundaries. Yet, the mechanisms of co-segregation and grain boundary phase decomposition in multi-component alloys are rather challenging to explore. In fact, quantitative investigation of grain boundary behaviors is mostly conducted for binary and a few ternary alloys. In this work, we apply the recently introduced CALPHAD-integrated density-based formalism [RSC Advances 10 (2020) 26728-26741] for considering co-segregation phenomena in alloys with an arbitrary number of components —the term ‘co-segregation’ here refers to co-evolution and any mutual interplay among the solute atoms during their interaction with a grain boundary. Quaternary Fe-Co-Mn-Cr alloy system is studied. We present two major advances beyond previous results: First, a co-segregation-induced multi-component grain boundary spinodal decomposition is quantitatively simulated for the first time. We found that in addition to its low cohesive energy and asymmetrical mixing enthalpy due to magnetic ordering, Mn plays a leading role in triggering interfacial phase decomposition by having a relatively large, concentration-dependent atomic mobility. Second, as an alternative to grain boundary phase diagrams proposed for binary and ternary alloys, we introduce the concept of co-segregation maps for grain boundary segregation screening and design in multi-component alloys. Applying the co-segregation maps, the nonlinear Mn and Cr co-segregation are discussed. Depicted on the alloying composition and phase space, the co-segregation maps enable the required insights to guide a safer, more controlled design of high-entropy alloys.

Numerical Study of a Solar Cell to Achieve the Highest InGaN Power Conversion Efficiency for the Whole In-Content Range.

A solar cell structure with a graded bandgap absorber layer based on InGaN has been proposed to overcome early predicted efficiency. Technological issues such as carrier concentration in the p- and n-type are based on the data available in the literature. The influence of carrier concentration-dependent mobility on the absorber layer has been studied, obtaining considerable improvements in efficiency and photocurrent density. Efficiency over the tandem solar cell theoretical limit has been reached. A current density of 52.95 mA/cm2, with an efficiency of over 85%, is determined for a PiN structure with an InGaN step-graded bandgap absorption layer and 65.44% of power conversion efficiency for the same structure considering piezoelectric polarization of fully-strained layers and interfaces with electron and hole surface recombination velocities of 10-3 cm/s.

On a generalized Cahn--Hilliard model with $p$-Laplacian

A generalized Cahn--Hilliard model in a bounded interval of the real line with no-flux boundary conditions is considered. The label ``generalized'' refers to the fact that we consider a concentration dependent mobility, the $p$-Laplace operator with $p > 1$ and a double well potential of the form $F(u)=\frac{1}{2\theta}|1-u^2|^\theta$, with $\theta > 1$; these terms replace, respectively, the constant mobility, the linear Laplace operator and the $C^2$ potential satisfying $F''(\pm1) > 0$, which are typical of the standard Cahn--Hilliard model. After investigating the associated stationary problem and highlighting the differences with the standard results, we focus the attention on the long time dynamics of solutions when $\theta\geq p > 1$. In the critical case $\theta= p > 1$, we prove exponentially slow motion of profiles with a transition layer structure, thus extending the well know results of the standard model, where $\theta=p=2$; conversely, in the supercritical case $\theta > p > 1$, we prove algebraic slow motion of layered profiles.

A pseudo-spectral based efficient volume penalization scheme for Cahn–Hilliard equation in complex geometries

In this paper, we have developed an efficient volume penalization based diffuse-filtering scheme to solve variable mobility based Cahn–Hilliard equation in complex geometries. The main novelty of the work is that a dealiased pseudo-spectral scheme with immersed interface method (IIM) is proposed for solving any generalized concentration-dependent mobility function-based Cahn–Hilliard (CH) equation in complicated computational domains. An indicator function based mobility parameter is introduced to perform simulation of binary spinodal decomposition problem at a lower computational expense in complex geometries by solving a single phase field equation. Due to the smooth removal of high frequency Fourier components, the solution of the present RK4 based diffuse-filtering scheme does not display spurious currents when suitable low-pass filtering strategy and adequately resolved mobility indicator are incorporated. The traditional and memory optimized zero padding schemes are also implemented to show the comparative performance of different dealiasing schemes for the variable mobility based Cahn–Hilliard equation. It is found that the diffuse-filtering scheme displays reasonable accuracy similar to the zero padding based schemes but its average CPU time is significantly lower, which indicates better computational performance of the scheme for the variable mobility Cahn–Hilliard equation. Time variation of the characteristic length scale during spinodal decomposition of a binary mixture agrees well with the analytical prediction. The optimal three stage SSPRK3 temporal scheme is employed and it is found that time step size can be increased approximately 1.4 times than the classical RK4 scheme reducing total CPU time. Oscillation free numerical solution and conservation of order parameter are obtained for the complex geometry based spinodal decomposition problem. A radially-averaged structure factor is introduced to quantify resolution issues of the dealiasing schemes for the spinodal decomposition problem in different complex geometries.

Lymphotonic activity of Ruscus extract, hesperidin methyl chalcone and vitamin C in human lymphatic smooth muscle cells

Besides actions including their venotonic, anti-inflammatory, and anti-oxidant effects, venoactive drugs are expected to act on edema via their action on lymphatics. The objective of this study was to evaluate the effect of the combination of Ruscus, hesperidin methyl chalcone and Vitamin C (Ruscus/HMC/Vit C) on intracellular calcium mobilization and contraction of human lymphatic smooth muscle cells (LSMCs) to better characterize the mechanism of its lymphotonic activity. Calcium mobilization was evidenced by videomicroscopy analysis of the fluorescence emitted by a specific Ca2+ sensitive dye and measured after injection of Ruscus/HMC/Vit C at 0.1, 0.3, 1.0, and 3.0mg/mL into LSMCs. Ruscus/HMC/Vit C induced a strong and reproducible concentration-dependent calcium mobilization in LSMCs. On the contrary, another venoactive drug used as comparator, micronized purified flavonoid fraction (MPFF), did not induce calcium mobilization whatever the tested concentration. Although alternative mechanisms of action may result in potential lymphotonic effects, the efficacy of lymphotonic products is nonetheless related to their stimulating effect on the contractile activity of the smooth muscle cells surrounding lymphatic vessels. In the light of the results obtained in this study, the direct effect of Ruscus/HMC/Vit C on LSMC contraction may partially explain its clinical efficacy on lymphotonic activity, as has been observed in terms of objective signs of edema as reported in the recent guidelines on chronic venous disease.

Numerical study of hybrid quantum dot light-emitting diode with different concentration of quantum dots in the emissive layer

In this study, a model for numerical simulation of carrier transport mechanism in the hybrid quantum dot light-emitting diodes (QD-LEDs) is presented. The carrier mobility in the polymer layer doped with quantum dots (QDs) was calculated by a proposed hopping mobility, which is a concentration-dependent mobility model based on the Gaussian distribution of density-of-states and the effective transport energy models. A QD-LED structure based on PVK:CdSe-QDs blend as the emissive layer with different QD concentrations were fabricated and their current density versus voltage (J–V) characteristic was measured. The numerical results were compared with experimental data, which indicates the ability of the proposed mobility model to describe the general trend of the electrical characteristic of the devices. Then, the exciton density profiles of the devices were extracted based on the continuity equation for singlet and triplet excitons, and the corresponding luminance characteristic of the devices was calculated. The resulted electrical and optical characteristics show that there is an optimal concentration for the QDs in the emissive layer of the QD-LEDs.

Influence of film morphology and crystallinity on charge carrier concentration-dependent hole mobility in hexamethyldisilazane treated Pentacene bottom contact devices

The effect of substrate temperature and deposition rate on the film morphology, crystallinity, and electronic properties of Pentacene transistors treated with hexamethyldisilazane (HMDS) is studied. The gate bias dependence of mobility is used to estimate the width of the density of states and thereby quantify the disorder of the highest occupied molecular orbital. A low deposition rate and the substrate held at room temperature are shown to be the optimal conditions for good mobility (0.20 cm2 V−1 s−1) and low electronic disorder (50 ± 10 meV). X-ray diffraction measurements are performed to quantify the ratio of the two crystalline phases (thin-film phase and bulk phase) present in the film. The crystalline phases, rather than grain size, plays a significant role in determining the charge carrier mobility. Film deposition with the substrate at room temperature leads to low electronic disorder as the film is composed of one crystalline phase (thin-film phase), while high substrate temperature makes the film increasingly polymorphic, leading to increased electronic disorder (up to 230 meV). A high deposition rate leads to poor morphology of Pentacene near the source/drain electrode edge, thereby leading to increased contact resistance and electronic disorder. Hence, a low growth rate at room temperature is required for HMDS treated substrates to induce good crystalline properties of the film in the channel region, which results in enhanced electronic properties of the transistors.

Error Analysis of an Unconditionally Energy Stable Local Discontinuous Galerkin Scheme for the Cahn–Hilliard Equation with Concentration-Dependent Mobility

Abstract In this paper, we mainly study the error analysis of an unconditionally energy stable local discontinuous Galerkin (LDG) scheme for the Cahn–Hilliard equation with concentration-dependent mobility. The time discretization is based on the invariant energy quadratization (IEQ) method. The fully discrete scheme leads to a linear algebraic system to solve at each time step. The main difficulty in the error estimates is the lack of control on some jump terms at cell boundaries in the LDG discretization. Special treatments are needed for the initial condition and the non-constant mobility term of the Cahn–Hilliard equation. For the analysis of the non-constant mobility term, we take full advantage of the semi-implicit time-discrete method and bound some numerical variables in L ∞ L^{\infty} -norm by the mathematical induction method. The optimal error results are obtained for the fully discrete scheme.

Strong well-posedness and inverse identification problem of a non-local phase field tumour model with degenerate mobilities

We extend previous weak well-posedness results obtained in Frigeri et al. (2017, Solvability, Regularity, and Optimal Control of Boundary Value Problems for PDEs, Vol. 22, Springer, Cham, pp. 217–254) concerning a non-local variant of a diffuse interface tumour model proposed by Hawkins-Daarud et al. (2012, Int. J. Numer. Method Biomed. Engng.28, 3–24). The model consists of a non-local Cahn–Hilliard equation with degenerate mobility and singular potential for the phase field variable, coupled to a reaction–diffusion equation for the concentration of a nutrient. We prove the existence of strong solutions to the model and establish some high-order continuous dependence estimates, even in the presence of concentration-dependent mobilities for the nutrient variable in two spatial dimensions. Then, we apply the new regularity results to study an inverse problem identifying the initial tumour distribution from measurements at the terminal time. Formulating the Tikhonov regularised inverse problem as a constrained minimisation problem, we establish the existence of minimisers and derive first-order necessary optimality conditions.

Charge-carrier photogeneration and extraction dynamics of polymer solar cells probed by a transient photocurrent nearby the regime of the space charge-limited current

To understand the complex behaviors of photogenerated charge carriers within polymer-based bulk-heterojunction-type solar cells, the charge-carrier photogeneration and extraction dynamics are simultaneously estimated using a transient photocurrent technique under various external-bias voltages, and a wide range of excitation intensities are analyzed. For this purpose, conventional devices with 80 nm thick active layers consisting of a blend of representative P3HT and PTB7 electron-donating polymers and proper electron-accepting fullerene derivatives were used. After the correction for the saturation behavior at a high excitation-intensity range nearby the regime of the space charge-limited current, the incident-photon-density-dependent maximum photocurrent densities at the initial peaks are discussed as the proportional measures of the charge-carrier-photogeneration facility. By comparing the total number of the extracted charge carriers to the total number of the incident photons and the number of the initially photogenerated charge carriers, the external quantum efficiencies as well as the extraction quantum efficiencies of the charge-carrier collection during a laser-pulse-induced transient photocurrent process were obtained. Subsequently, the charge-carrier concentration-dependent mobility values were obtained, and they are discussed in consideration of the additional influences of the charge-carrier losses from the device during the charge-carrier extraction that also affects the photocurrent-trace shape.

(Keynote) Proton-Tunable Analog Transistor Using a Coordination Polymer

Artificial neural networks (ANN), an alternative to digital logic, can supersede Moore’s law limitations, solve complex non-numeric problems, and are compatible with low-power analog hardware that can reduce energy consumption. Analog devices emulating nerve synapses offer an alternative to digital logic for ANN. Ion-based switches, such as memristors, could potentially address these challenges. However, correlated ion and charge transport in their conducting channels and numerous issues with the switching materials are a barrier to development and optimization of these potentially revolutionary concepts. Recently, Talin and coworkers developed a novel three-terminal redox transistor (RT)[1] based on conducting organic polymers (PEDOT:PSS) that can overcome the inherent limitations of two-terminal memristors for ANN and low-power computing (Fig. 1). Dozens to hundreds of conducting states are feasible, with fast switching and much lower switching voltages than CMOS transistors. They also demonstrated that these polymer redox transistors endure >109 ‘read-write’ operations and project that switching times <100 ns are feasible.[2] Gaining fundamental insight into the performance-controlling phenomena in ion-based switches such as the RT is difficult because ionic and electronic charge transport are correlated in these devices. In the RT, the complex morphology of the polymer electrodes, which have both ordered and disordered regions resembling “cooked spaghetti”[3] affects the density of states (DOS), leading to carrier concentration-dependent mobilities.[4] Consequently, disentangling the correlated effects of morphology, composition, and device architecture requires new synthetic approaches, much greater control over disorder, and operando experimental probes that can generate spatially resolved potentials and composition and microstructural maps.We are developing self-assembled nanoporous materials (SNM) as a new class of mixed conductors to enable independent control of ion and electronic charge transport. SNM offer unprecedented control over porosity to confine and rapidly transport ions, as well as long-range order and synthetic versatility to tailor electronic conductivity. In this presentation we will discuss the requirements for such materials, in particular, highlighting the potential of nanoporous framework materials to provide tailorable pore dimensions with chemical functionalities and redox behavior suitable for ion-based switching. As a starting point for determining structure-function relationships, we are considering redox-active MOFs, which can provide tunable electrical conductivity and fast ion transport combined with a structure having long-range order. An experimental device incorporating these materials will be described to illustrate the potential for using MOFs in RT devices. Fabrication methods and device assembly will also be discussed. Data from operando measurements of local composition and state-of-charge will be presented together with maps relating local morphology with conductivity to create a detailed picture of material and device performance. Finally, results from analytical modeling will be compared with these experimental to determine the validity of current models to describe the coupled ion and charge transport. Y. van de Burgt; E. Lubberman; E. J. Fuller; S. T. Keene; G. C. Faria; S. Agarwal; M. J. Marinella; A. A. Talin; A. Salleo "A non-volatile organic electrochemical device as a low-voltage artificial synapse for neuromorphic computing," Nat. Mater. 2017, 16, 414, 10.1038/nmat4856.E. J. Fuller; S. T. Keene; A. Melianas; Z. Wang; S. Agarwal; Y. Li; Y. Tuchman; C. D. James; M. J. Marinella; J. J. Yang; A. Salleo; A. A. Talin "Parallel programming of an ionic floating-gate memory array for scalable neuromorphic computing," Science 2019, 364, 570, 10.1126/science.aaw5581.R. Noriega; J. Rivnay; K. Vandewal; F. P. V. Koch; N. Stingelin; P. Smith; M. F. Toney; A. Salleo "A general relationship between disorder, aggregation and charge transport in conjugated polymers," Nat. Mater. 2013, 12, 1038, 10.1038/nmat3722.J. T. Friedlein; J. Rivnay; D. H. Dunlap; I. McCulloch; S. E. Shaheen; R. R. McLeod; G. G. Malliaras "Influence of disorder on transfer characteristics of organic electrochemical transistors," Appl. Phys. Lett. 2017, 111, 10.1063/1.4993776. Figure 1

AGTR1 Is Overexpressed in Neuroendocrine Neoplasms, Regulates Secretion and May Potentially Serve as a Target for Molecular Imaging and Therapy.

Simple SummaryClinical management of neuroendocrine neoplasms (NEN), especially of those low in target molecules such as somatostatin receptors, may benefit from the discovery of novel targets. This study identified and confirmed angiotensin II (ATII) as a strong activator of signaling in NEN cells and its cognate receptor AGTR1 as overexpressed in human small intestinal NEN. NEN cells with high AGTR1 expression exhibited cellular activation and secretion upon stimulation with ATII. AGTR1 ligand saralasin coupled to a fluorescent dye demonstrated tumor accumulation in an animal model of NEN. This proof of concept establishes AGTR1 as a novel target in NEN, paving the way for its potential use in diagnostic PET imaging and radioligand therapy.This study identified and confirmed angiotensin II (ATII) as a strong activator of signaling in neuroendocrine neoplasm (NEN) cells. Expression analyses of the ATII receptor type 1 (AGTR1) revealed an upregulation of mRNA levels (RT-qPCR) and radioligand binding (autoradiography) in small-intestinal (n = 71) NEN tissues compared to controls (n = 25). NEN cells with high AGTR1 expression exhibited concentration-dependent calcium mobilization and chromogranin A secretion upon stimulation with ATII, blocked by AGTR1 antagonism and Gαq inhibition. ATII also stimulated serotonin secretion from BON cells. AGTR1 ligand saralasin was coupled to a near-infrared fluorescent (NIRF) dye and tested for its biodistribution in a nude mouse model bearing AGTR1-positive BON and negative QGP-1 xenograft tumors. NIRF imaging showed significantly higher uptake in BON tumors. This proof of concept establishes AGTR1 as a novel target in NEN, paving the way for translational chelator-based probes for diagnostic PET imaging and radioligand therapy.

A study on the effect of film crystallinity and morphology on charge carrier concentration-dependent hole mobility in pentacene thin-film transistors: advantages of high deposition rate

The combined effect of deposition rate and substrate temperature on the film crystallinity, morphology, and electronic properties of pentacene is studied. It is shown that the channel mobility in polycrystalline pentacene thin-film transistors is relatively immune to substrate temperature, and the films offer good hole mobility when grown at a high rate. This is advantageous when high throughput with low deviation in electrical parameters over devices are required. The surface morphology is characterized by atomic force microscopy measurements and the crystallinity is studied using x-ray diffraction. The effect of growth parameters on the crystalline phases of pentacene is correlated to the charge carrier transport. It is found that the field-effect mobility is primarily affected by the crystalline phases of the film rather than the grain size. The charge carrier dependence of the hole mobility is used to parameterize the dispersion (width) in the density of states (DOS) of the highest occupied molecular orbital of the films in the transistor channel region. It is found that the presence of multiple phases in the path of the charge carrier flow increases the dispersion of the DOS.

Atomic transport in B2-ordered Al(Fe,Ni) alloys: Tracer-interdiffusion couple approach

A novel tracer-interdiffusion couple technique is utilized to measure the concentration-dependent tracer- (59Fe) diffusion coefficients in the B2-ordered Al50(Ni,Fe)50 alloys at 1373 K in a single experiment. The influence of variable molar volume on the diffusion coefficients is examined. The tracer diffusion coefficients determined under chemical gradients are shown to be in an excellent agreement with the diffusivities measured independently for homogeneous alloys. The tracer diffusion coefficients of Fe are observed to increase strongly with an increase of the Fe concentration. Strong up-hill diffusion of Al hinders a reliable determination of the interdiffusion coefficients with a single diffusion couple. The results confirm a high potential of the tracer-interdiffusion couple technique for producing highly accurate concentration-dependent mobility data in multi-component systems.

Mobility Models Based on Forward Current-Voltage Characteristics of P-type Pseudo-Vertical Diamond Schottky Barrier Diodes.

Compared with silicon and silicon carbide, diamond has superior material parameters and is therefore suitable for power switching devices. Numerical simulation is important for predicting the electric characteristics of diamond devices before fabrication. Here, we present numerical simulations of p-type diamond pseudo-vertical Schottky barrier diodes using various mobility models. The constant mobility model, based on the parameter μconst, fixed the hole mobility absolutely. The analytic mobility model resulted in temperature- and doping concentration-dependent mobility. An improved model, the Lombard concentration, voltage, and temperature (CVT) mobility model, considered electric field-dependent mobility in addition to temperature and doping concentration. The forward voltage drop at 100 A/cm2 using the analytic and Lombard CVT mobility models was 2.86 and 5.17 V at 300 K, respectively. Finally, we used an empirical mobility model based on experimental results from the literature. We also compared the forward voltage drop and breakdown voltage of the devices, according to variations in p- drift layer thickness and cathode length. The device successfully achieved a low specific on-resistance of 6.8 mΩ∙cm2, a high breakdown voltage of 1190 V, and a high figure-of-merit of 210 MW/cm2.

Thermoelectric transport properties in Bi-doped SnTe–SnSe alloys

Numerous endeavors have been made to advance thermoelectric SnTe for potential applications. Effective strategies focus on the manipulation of transport properties, including valence band convergence, resonate state, and defect engineering. It has been demonstrated that alloying trivalent Bi or chalcogenide SnSe alone in SnTe can trigger an inherent enhancement of thermoelectric performance. However, what the critical role in the transport valence band co-doping Bi and Se in SnTe plays is still unclear. Particularly, fully evaluating the effect of band convergence on the carrier concentration-dependent weighted mobility, which dominates the electronic performance, is primary and essential for designing excellent thermoelectric materials. Here, we report that Bi doping in SnTe–SnSe alloys can derive a distinct decrease in the energy offset between the two valence bands, thus improving the density-of-state effective mass by only slightly deteriorating the mobility. The well-established theoretical model reveals that the Bi-doping-induced band convergence and the optimized carrier concentration actually enhance the weighted mobility, contributing to the improvement of electronic performance. Moreover, the Debye–Callaway model demonstrates the origin of the reduced lattice thermal conductivity. The present results confirm the potential of transport engineering in promoting thermoelectric performance.