Signatures of Room-Temperature Quantum Interference in Molecular Junctions.

ConspectusDuring the past decade or so, research groups around the globe have sought to answer the question: "How does electricity flow through single molecules?" In seeking the answer to this question, a series of joint theory and experimental studies have demonstrated that electrons passing through single-molecule junctions exhibit exquisite quantum interference (QI) effects, which have no classical analogues in conventional circuits. These signatures of QI appear even at room temperature and can be described by simple quantum circuit rules and a rather intuitive magic ratio theory. The latter describes the effect of varying the connectivity of electrodes to a molecular core and how electrical conductance can be controlled by the addition of heteroatoms to molecular cores. The former describes how individual moieties contribute to the overall conductance of a molecule and how the overall conductance can change when the connectivities between different moieties are varied. Related circuit rules have been derived and demonstrated, which describe the effects of connectivity on Seebeck coefficients of organic molecules. This simplicity arises because when a molecule is placed between two electrodes, charge transfer between the molecule and electrodes causes the molecular energy levels to adjust, such that the Fermi energy (EF) of the electrodes lies within the energy gap between the highest occupied molecular orbital and lowest unoccupied molecular orbital. Consequently, when electrons of energy EF pass through a molecule, their phase is protected and transport takes place via phase-coherent tunneling. Remarkably, these effects have been scaled up to self-assembled monolayers of molecules, thereby creating two-dimensional materials, whose room temperature transport properties are controlled by QI. This leads to new molecular design strategies for increasing the on/off conductance ratio of molecular switches and to improving the performance of organic thermoelectric materials. In particular, destructive quantum interference has been shown to improve the Seebeck coefficient of organic molecules and increase their on/off ratio under the influence of electrochemical gating. The aim of this Account is to introduce the novice reader to these signatures of QI in molecules, many of which have been identified in joint studies involving our theory group in Lancaster University and experimental group in Bern University.

Contribution of portable obstetric ultrasound service innovation in averting maternal and neonatal morbidities and mortalities at semi-urban health centers of Ethiopia: a retrospective facility-based study.

BACKGROUND: The maternal and neonatal mortalities in Ethiopia are high. To achieve the Sustainable Development Goals, innovations in ultrasound scanning and surveillance activities have been implemented at health centers for over 2 years. This study aims to estimate the contribution of obstetric ultrasound services on averted maternal and neonatal morbidities and mortalities in Ethiopia. METHODS: A retrospective facility-based cross-sectional study design was conducted in 25 selected health centers. Data were extracted from prenatal ultrasound registers. SPSS version 25 was used for analysis. To claim statistically significant relationship among sartorial variables, a chi-square test was analyzed and P < 0.05 was the cut-off point. RESULTS: Over the 2 years, 12,975 pregnant women were scanned and 52.8% of them were residing in rural areas. Abnormal ultrasound was reported in 12.7% and 98.4% of them were referred for confirmation of diagnosis and treatment. The ultrasound service has contributed to the prevention of 1,970 maternal and 19.05 neonatal morbidities and mortalities per 100,000 and 1,000 live births respectively. The averted morbidities and mortalities showed a statistically significant difference among women residing in rural and semi-urban areas, X,2 df (10) = 24.07, P = 0. 007 and X,2 df (5) = 20.87. P = 0.00, 1 respectively. CONCLUSION: After availing the appropriate ultrasound machines with essential supplies and capacitating mid-level providers, significant number of high-risk pregnant women were identified on time and managed or referred to health facilities with safe delivery services. Therefore, scaling-up limited obstetric ultrasound services in similar setups will contribute to achieving the Sustainable Development Goals by 2030. It is recommended to enhance community awareness for improved utilization of ultrasound services by pregnant women before the 24th week of gestational age.

Experiences of midwives on Vscan limited obstetric ultrasound use: a qualitative exploratory study.

BACKGROUND: Ethiopia is a low-income country located in the horn of Africa's sub-Saharan region, with very high incidences of maternal and neonatal mortality. Quality antenatal care improves perinatal health outcomes. The USAID funded Transform: Primary Health Care Activity in collaboration with the Ministry of Health and GE Healthcare introduced Vscan limited obstetric ultrasound services in 120 health centers in Ethiopia. So far, the experiences and opinions of midwives on their use have not been explored and described within the local context. This study therefore aims to explore and describe the experiences and opinions of midwives on Vscan limited obstetric ultrasound services at health centers within Ethiopia. METHODS: An exploratory and descriptive qualitative study was conducted in Amhara, Oromia, and Southern Nations, Nationalities and Peoples' (SNNP) regions of Ethiopia. Twenty-four participants were selected through a purposeful sampling technique. In-depth individual interviews with trained midwives with practical hands-on limited obstetric ultrasound service provision experience were conducted. The thematic analysis was conducted manually. RESULTS: The qualitative data analysis on the experiences and opinions of midwives revealed three themes, namely: individual perception of self-efficacy, facilitators, and barriers of limited obstetric ultrasound services. The basic ultrasound training, which was unique in its organization and arrangement, prepared and built the self-efficacy of trainees in executing their expected competencies. Support of health systems and health managers in dedicating space, availing essential supplies, and assigning human resources emerged as facilitators of the initiated limited obstetric ultrasound services, whereas high workload on one or two ultrasound trained midwives, interruption of essential supplies like paper towels, gel, and alternative power sources were identified as barriers for limited ultrasound services. CONCLUSION: This study explored the experiences and opinions of midwives who were trained on the provision of limited obstetric ultrasound services and served the community in health centers in rural parts of Ethiopia. The results of this study revealed the positive impacts of the intervention on the perceived self-efficacy, facilitation, and breaking-down of barriers to obstetric ultrasound services. Before scaling-up limited obstetric ultrasound interventions, health managers should ensure and commit to availing essential supplies (e.g., paper towels, ultrasound gel, and large memory hard discs), arranging private rooms, and training other mid-level health professionals. In addition, improving pregnant women's literacy on the national schedule for ultrasound scanning services is recommended.

Implementing a modified World Health Organization safe childbirth checklist in health centers of Ethiopia: a pre and post intervention study.

BACKGROUND: Childbirth is a complex process, and checklists are useful tools to remember steps of such complex processes. The World Health Organization safe childbirth checklist is a tool used to improve the quality of care provided to women giving birth. The checklist was modified by Ministry of Health and was introduced to health centers in Ethiopia by the USAID Transform: Primary Health Care Activity. METHODS: A pre and post intervention study design with prospective data collection was employed. The availability of essential childbirth supplies and adherence of health care providers to essential birth practices were compared for the pre and post intervention periods. RESULTS: The pre and post intervention assessments were conducted in 247 and 187 health centers respectively. A statistically significant improvement from 63.6% pre intervention to 83.5% post intervention was observed in the availability of essential childbirth supplies, t (389.7) = - 7.1, p = 0.000. Improvements in adherence of health care providers to essential birth practices were observed with the highest being at pause point three (26.2%, t (306.3) = - 10.6, p = 0.000) followed by pause point four (21.1%, t (282.5) = - 8.0, p = 0.000), and pause point two (18.2%, t (310.8) = - 9.7, p = 0.000). The least and statistically non-significant improvement was observed at pause point one (3.3%, t (432.0) = - 1.5, p = 0.131). CONCLUSION: Improvement in availability of essential childbirth supplies and adherence of health care providers towards essential birth practices was observed after introduction of a modified World Health Organization safe childbirth checklist. Scale up of the use of the checklist is recommended.

Comparison of maternal and child health service performances following a leadership, management, and governance intervention in Ethiopia: a propensity score matched analysis.

BACKGROUND: Leadership, management, and governance (LMG) interventions play a significant role in improving management systems, enhancing the work climate, and creating responsive health systems. Hence, the Ethiopian Ministry of Health with the support of the USAID Transform: Primary Health Care project has been implementing LMG interventions to improve performances of primary healthcare entities. The purpose of this evaluation was to compare maternal and child health service performances and overall health system strengthening measurement results of primary health care entities by LMG intervention exposed groups. METHODS: The study used a cross-sectional study design with a propensity matched score analysis, and was conducted from August 28, 2017, to September 30, 2018, in Amhara, Oromia, Tigray, and Southern Nations, Nationalities, and Peoples' (SNNP) regions. Data collection took place through interviewer and self-administered questionnaires among 227 LMG intervention exposed and 227 non-exposed health workers. Propensity score matched analysis was used to balance comparison groups with respect to measured covariates. RESULTS: The mean overall maternal and child health key performance indicator score with standard deviation (± SD) for the LMG intervention exposed group was 63.86 ± 13.16 and 57.02 ± 13.71 for the non-exposed group. The overall health system strengthening score for the LMG intervention exposed group (mean rank = 269.31) and non-exposed group (mean rank = 158.69) had statistically significant differences (U = 10.145, z = - 11.175, p = 0.001). In comparison with its counterpart, the LMG exposed group had higher average performances in 3.54, 3.51, 2.64, 3.00, 1.07, and 3.34 percentage-points for contraceptive acceptance rate, antenatal care, skilled birth attendance, postnatal care, full immunization, and growth monitoring services, respectively. CONCLUSION: There were evidences on the positive effects of the LMG intervention on increased maternal and child health services performances at primary healthcare entities. Moreover, health facilities with LMG intervention exposed health workers had higher and statistically significant differences in management systems, work climates, and readiness to face new challenges. Therefore, this study generated evidence for integrating LMG interventions to improve the performance of primary healthcare entities and maternal and child service uptake of community members, which contributes to the reduction of maternal and child deaths.

Scale-Up of Room-Temperature Constructive Quantum Interference from Single Molecules to Self-Assembled Molecular-Electronic Films.

The realization of self-assembled molecular-electronic films, whose room-temperature transport properties are controlled by quantum interference (QI), is an essential step in the scale-up of QI effects from single molecules to parallel arrays of molecules. Recently, the effect of destructive QI (DQI) on the electrical conductance of self-assembled monolayers (SAMs) has been investigated. Here, through a combined experimental and theoretical investigation, we demonstrate chemical control of different forms of constructive QI (CQI) in cross-plane transport through SAMs and assess its influence on cross-plane thermoelectricity in SAMs. It is known that the electrical conductance of single molecules can be controlled in a deterministic manner, by chemically varying their connectivity to external electrodes. Here, by employing synthetic methodologies to vary the connectivity of terminal anchor groups around aromatic anthracene cores, and by forming SAMs of the resulting molecules, we clearly demonstrate that this signature of CQI can be translated into SAM-on-gold molecular films. We show that the conductance of vertical molecular junctions formed from anthracene-based molecules with two different connectivities differ by a factor of approximately 16, in agreement with theoretical predictions for their conductance ratio based on CQI effects within the core. We also demonstrate that for molecules with thioether anchor groups, the Seebeck coefficient of such films is connectivity dependent and with an appropriate choice of connectivity can be boosted by ∼50%. This demonstration of QI and its influence on thermoelectricity in SAMs represents a critical step toward functional ultra-thin-film devices for future thermoelectric and molecular-scale electronics applications.

Association of interleukin-17A gene polymorphisms and susceptibility to systemic lupus erythematosus in Egyptian children and adolescents: a multi-centre study.

BACKGROUND: Recently, the interleukin-17A (IL-17A) gene has emerged as a potential candidate gene for autoimmune disorders, including systemic lupus erythematosus (SLE). OBJECTIVES: This study aimed to investigate whether IL-17A polymorphisms at rs2275913 G/A, rs8193036 C/T and rs3748067 C/T could be susceptibility markers for juvenile-onset SLE (JSLE) and lupus nephritis (LN) in Egyptian children and adolescents. METHODS: In this multi-centre study, we genotyped 320 patients diagnosed with JSLE and 320 matched control children for three IL-17A polymorphisms at rs2275913 G/A, rs8193036 C/T and rs3748067 C/T using TaqMan probe-based real-time polymerase chain reaction. Meanwhile, IL-17A serum levels were assessed using ELISA. RESULTS: The IL-17 rs2275913 A/A genotype and A allele were more represented in JSLE patients compared to the control group (21% vs. 7%, odds ratio (OR) = 3.8, 95% confidence interval (CI) 1.78-5.5, p = 0.001, pBonf = 0.003 for the A/A genotype; 37% vs. 29%, OR = 1.4, 95% CI 1.11-1.8, p = 0.003, pBonf = 0.009 for the A allele. No significant difference was found for IL-17 rs8193036 and rs3748067 single nucleotide polymorphisms (SNPs) in genotype distribution or allele frequencies (p>0.05). Patients carrying the IL-17 rs2275913 A/A genotype and A allele were more likely to develop LN (OR = 5.64, 95% CI 2.39-13.77, pBonf = 0.001 for the A/A genotype; OR = 2.73, 95% CI 1.84-4.07, pBonf = 0.02 for the A allele). CONCLUSION: The IL-17 rs2275913 A allele and A/A genotype were associated with high IL-17 serum levels and may contribute to susceptibility to JSLE and the development of LN in Egyptian children and adolescents. However, no significant association was evident between the studied IL-17A SNPs and other clinical phenotypes, disease activity scores or laboratory profile of JSLE.

Leadership, governance and management for improving district capacity and performance: the case of USAID transform: primary health care.

BACKGROUND: Primary health care (PHC) in Ethiopia serves as the main entry point for preventive, promotive and curative health services. The district health office is responsible for the planning, implementation and evaluation of all district health activities. In addition, district health offices manage service delivery facilities working on provision of PHC - primary hospitals, health centers and health posts. As the leader of the health care system tier, district health management must ensure direction, alignment and commitment within teams and organizations and make sure that achievements are consistent with the vision, values and strategy of the organization. USAID Transform: Primary Health Care provides diverse support to improve district health manager competencies including in-service trainings followed by planning and implementation of performance improvement projects and on-the-job mentoring and support. METHODS: This study was conducted to compare district level capacity and performances between leadership, management and governance (LMG) and non-LMG districts. Project outcome monitoring data that shows the performance of districts was collected from 284 districts from January to December 2019. The study was carried out using a comparative-cross sectional study design, which assessed and compared district health office level indicators. Districts were classified into two categories: LMG and non-LMG districts. The study compared data from 94 LMG and 190 non-LMG districts. Propensity score matching was used to control the effect of differences between LMG and non-LMG districts. RESULTS: Results of the independent samples t-test revealed that LMG districts scored better average performances of 61.8 ± 121.45 standard deviation (SD) compared to non-LMG districts 56.89 ± 110.39 SD, with t (282243) = - 3.407317 and p < 0.001, two-tailed. The difference of 4.9 percentage unit in the average performance indicated a statistically significant difference between the LMG and non-LMG districts. CONCLUSION: District level leadership development program contributes to improving district capacity, structure and management practices, and quality of care.

Correction: Connectivity dependence of Fano resonances in single molecules.

Correction for 'Connectivity dependence of Fano resonances in single molecules' by Ali K. Ismael et al., Phys. Chem. Chem. Phys., 2017, 19, 6416-6421.

Molecular design and control of fullerene-based bi-thermoelectric materials.

Molecular junctions are a versatile test bed for investigating nanoscale thermoelectricity and contribute to the design of new cost-effective environmentally friendly organic thermoelectric materials. It was suggested that transport resonances associated with discrete molecular levels could play a key role in thermoelectric performance, but no direct experimental evidence has been reported. Here we study single-molecule junctions of the endohedral fullerene Sc3N@C80 connected to gold electrodes using a scanning tunnelling microscope. We find that the magnitude and sign of the thermopower depend strongly on the orientation of the molecule and on applied pressure. Our calculations show that Sc3N inside the fullerene cage creates a sharp resonance near the Fermi level, whose energetic location, and hence the thermopower, can be tuned by applying pressure. These results reveal that Sc3N@C80 is a bi-thermoelectric material, exhibiting both positive and negative thermopower, and provide an unambiguous demonstration of the importance of transport resonances in molecular junctions.

Connectivity dependence of Fano resonances in single molecules.

Using a first principles approach combined with analysis of heuristic tight-binding models, we examine the connectivity dependence of two forms of quantum interference in single molecules. Based on general arguments, Fano resonances are shown to be insensitive to connectivity, while Mach-Zehnder-type interference features are shown to be connectivity dependent. This behaviour is found to occur in molecular wires containing anthraquinone units, in which the pendant carbonyl groups create Fano resonances, which coexist with multiple-path quantum interference features.

Discriminating single-molecule sensing by crown-ether-based molecular junctions.

Crown-ether molecules are well known to selectively bind alkali atoms, so by incorporating these within wires, any change in electrical conductance of the wire upon binding leads to discriminating sensing. Using a density functional theory-based approach to quantum transport, we investigate the potential sensing capabilities of single-molecule junctions formed from crown ethers attached to anthraquinone units, which are in turn attached to gold electrodes via alkyl chains. We calculate the change in electrical conductance for binding of three different alkali ions (lithium, sodium, and potassium). Depending on the nature of the ionic analyte, the conductance is enhanced by different amounts. This change in electrical conductance is due to charge transfer from the ion to molecular wire causing the molecular resonances to shift closer to the electrode Fermi energy.

Side-Group-Mediated Mechanical Conductance Switching in Molecular Junctions.

A key target in molecular electronics has been molecules having switchable electrical properties. Switching between two electrical states has been demonstrated using such stimuli as light, electrochemical voltage, complexation and mechanical modulation. A classic example of the latter is the switching of 4,4'-bipyridine, leading to conductance modulation of around 1 order of magnitude. Here, we describe the use of side-group chemistry to control the properties of a single-molecule electromechanical switch, which can be cycled between two conductance states by repeated compression and elongation. While bulky alkyl substituents inhibit the switching behavior, π-conjugated side-groups reinstate it. DFT calculations show that weak interactions between aryl moieties and the metallic electrodes are responsible for the observed phenomenon. This represents a significant expansion of the single-molecule electronics "tool-box" for the design of junctions with electromechanical properties.

Energy gap and aromatic molecular rings.

The manuscript combines rational density functional theory simulations and experimental data to investigate the electrical properties of eight polycyclic aromatic hydrocarbons (PAHs). The optimized geometries reveal a preference for one-row, two-row and three-row ring distributions. Band structure plots demonstrate an inverse correlation between the number of aromatic rings and band gap size, with a specific order observed across the PAHs. Gas phase simulations support these findings, though differences in values are noted compared to the literature. Introducing a two-row ring distribution concept resolves discrepancies, particularly in azulene. The B3LYP function successfully bridges theoretical and experimental gaps, particularly in large PAHs. The manuscript highlights the potential for designing electronic devices based on different-sized PAHs, emphasizing a multi-ring distribution approach and opening new avenues for practical applications.

Structure-Property Relationships in PVDF/SrTiO3/CNT Nanocomposites for Optoelectronic and Solar Cell Applications.

The optical properties of polyvinylidene fluoride (PVDF) polymer nanocomposite films incorporating SrTiO3/carbon nanotubes (CNTs) as nanofillers are investigated. PVDF/SrTiO3/CNTs films were prepared by the solution casting technique. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) analyses confirmed the incorporation of SrTiO3/CNTs into the PVDF matrix. The addition of nanofillers influenced the crystalline structure, morphology, and optical properties of the films. SEM images showed spherulite morphology, which is a spherical aggregate of crystalline polymer chains. The addition of a SrTiO3/CNTs nanofiller modified the polymer's electronic structure, causing a variation in the energy gap. The addition of SrTiO3/CNTs at 0.1 wt% increased the band gap, refractive index, and nonlinear optical properties of the PVDF films. These improvements indicate the potential of these nanocomposite films in optoelectronic applications such as solar cells, image sensors, and organic light-emitting diodes.

Orientational Effects and Molecular-Scale Thermoelectricity Control.

The orientational effect concept in a molecular-scale junction is established for asymmetric junctions, which requires the fulfillment of two conditions: (1) design of an asymmetric molecule with strong distinct terminal end groups and (2) construction of a doubly asymmetric junction by placing an asymmetric molecule in an asymmetric junction to form a multicomponent system such as Au/Zn-TPP+M/Au. Here, we demonstrate that molecular-scale junctions that satisfy the conditions of these effects can manifest Seebeck coefficients whose sign fluctuates depending on the orientation of the molecule within the asymmetric junction in a complete theoretical investigation. Three anthracene-based compounds are investigated in three different scenarios, one of which displays a bithermoelectric behavior due to the presence of strong anchor groups, including pyridyl and thioacetate. This bithermoelectricity demonstration implies that if molecules with alternating orientations can be placed between an asymmetric source and drain, they can be potentially utilized for increasing the thermovoltage in molecular-scale thermoelectric energy generators (TEGs).

A High-Performance Cr2O3/CaCO3 Nanocomposite Catalyst for Rapid Hydrogen Generation from NaBH4.

This study aims to prepare new nanocomposites consisting of Cr2O3/CaCO3 as a catalyst for improved hydrogen production from NaBH4 methanolysis. The new nanocomposite possesses nanoparticles with the compositional formula Cr2-xCaxO3 (x = 0, 0.3, and 0.6). These samples were prepared using the sol-gel method, which comprises gelatin fuel. The structure of the new composites was studied using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, environmental scanning electron microscopy (ESEM), and X-ray spectroscopy (XPS). The XRD data showed the rhombohedral crystallinity of the studied samples, and the average crystal size was 25 nm. The FTIR measurements represented the absorption bands of Cr2O3 and CaO. The ESEM micrographs of the Cr2O3 showed the spherical shape of the Cr2O3 nanoparticles. The XPS measurements proved the desired oxidation states of the Cr2-xCaxO3 nanoparticles. The optical band gap of Cr2O3 is 3.0 eV, and calcium doping causes a reduction to 2.5 and 1.3 eV at 15.0 and 30.0% doping ratios. The methanolysis of NaBH4 involved accelerated H2 production when using Cr2-xCaxO3 as a catalyst. Furthermore, the Cr1.7Ca0.3O3 catalyst had the highest hydrogen generation rate, with a value of 12,750 mL/g/min.

20-State Molecular Switch in a Li@C60 Complex.

A substantial potential advantage of industrial electric and thermoelectric devices utilizing endohedral metallofullerenes (EMFs) is their ability to accommodate metallic moieties inside their empty cavities. Experimental and theoretical studies have elucidated the merit of this extraordinary feature with respect to developing electrical conductance and thermopower. Published research studies have demonstrated multiple state molecular switches initiated with 4, 6, and 14 distinguished switching states. Through comprehensive theoretical investigations involving electronic structure and electric transport, we report 20 molecular switching states that can be statistically recognized employing the endohedral fullerene Li@C60 complex. We propose a switching technique that counts on the location of the alkali metal that encapsulates inside a fullerene cage. The 20 switching states correspond to the 20 hexagonal rings that the Li cation energetically prefers to reside close to. We demonstrate that the multiswitching feature of such molecular complexes can be controlled by taking advantage of the off-center displacement and charge transfer from the alkali metal to the C60 cage. The most energetically favorable optimization suggests 1.2-1.4 Å off-center displacement, and Mulliken, Hirshfeld, and Voronoi simulations articulate that the charge migrates from the Li cation to C60 fullerene; however, the amount of the charge transferred depends on the nature and location of the cation within the complex. We believe that the proposed work suggests a relevant step toward the practical application of molecular switches in organic materials.

Impact of the terminal end-group on the electrical conductance in alkane linear chains.

This research presents comprehensive theoretical investigations of a series of alkane-based chains using four different terminal end groups including amine -NH2, thiomethyl -SMe, thiol -SH and direct carbon contact -C. It is widely known that the electrical conductance of single molecules can be tuned and boosted by chemically varying their terminal groups to metal electrodes. Here, we demonstrate how different terminal groups affect alkane molecules' electrical conductance. In general, alkane chain conductance decreases exponentially with length, regardless of the anchor group types. In these simulations the molecular length varies from 3 to 8 -CH2 units, with 4 different linker groups; these simulations suggest that the conductances follow the order G C > G SH > G SMe > G NH2 . The DFT prediction order of the 4 anchors is well supported by STM measurements. This work demonstrates an excellent correlation between our simulations and experimental measurements, namely: the percent difference ΔG, exponential decay slopes, A constants and ß factors at different molecular alkane chain lengths.

Quantum Interference and Contact Effects in the Thermoelectric Performance of Anthracene-Based Molecules.

We report on the single-molecule electronic and thermoelectric properties of strategically chosen anthracene-based molecules with anchor groups capable of binding to noble metal substrates, such as gold and platinum. Specifically, we study the effect of different anchor groups, as well as quantum interference, on the electric conductance and the thermopower of gold/single-molecule/gold junctions and generally find good agreement between theory and experiments. All molecular junctions display transport characteristics consistent with coherent transport and a Fermi alignment approximately in the middle of the highest occupied molecular orbital/lowest unoccupied molecular orbital gap. Single-molecule results are in agreement with previously reported thin-film data, further supporting the notion that molecular design considerations may be translated from the single- to many-molecule devices. For combinations of anchor groups where one binds significantly more strongly to the electrodes than the other, the stronger anchor group appears to dominate the thermoelectric behavior of the molecular junction. For other combinations, the choice of electrode material can determine the sign and magnitude of the thermopower. This finding has important implications for the design of thermoelectric generator devices, where both n- and p-type conductors are required for thermoelectric current generation.