Carrier Donors Research Articles

O-233 The current landscape for carrier screening in donor conception; a game of chance for donors and recipients?

Abstract Study question How do international regulatory and commercial factors influence donor carrier screening and pose dilemmas for donors, clinics, and recipients. Summary answer Inconsistencies in international carrier screening guidelines and practice for donor conception create a two-tier system for donors and recipients. What is known already Carrier screening is used to identify those who are at risk to have a child with an autosomal recessive or X-linked genetic disorder. Donor banks adopt a commercially viable approach for carrier screening for their market and export, which creates inequalities in donor recruitment and reproductive risk for recipients. For example, UK guidelines require donors to be screened only for cystic fibrosis, with non-European donors screened for conditions known to be more common by ancestry. Real-world pan-ethnic approaches, however, are taken in varying degrees in other countries via extended carrier screening, posing dilemmas for donors, recipients, and clinics. Study design, size, duration Using current available public information, 14 UK, European, and US donor banks were surveyed to understand the screening level for recessive conditions and how this was conveyed to the patient or clinic client. Separately, expanded carrier screening (ECS) results (283 - 502 genes) from 1742 prospective donors from a > 6 year period at a US sperm bank were analysed to calculate acceptance rates if minimal screening and exclusion criteria were applied. Participants/materials, setting, methods UK, European, and US donor gamete banks were identified and surveyed using public information (2023). Separately, internal data from a US sperm bank related to ECS results from 2017 – 2023 was extracted, collated, and evaluated against the UK donor sperm genetic screening guidelines. Main results and the role of chance All donor banks surveyed state donors are genetically screened. For recessive conditions, UK and European banks screened for a small panel of between 3-20 genes, published on a general screening page on the donor bank website, and exclude donors that are carriers. Some offer an additional paid ECS genetic matching service without revealing what the donor or recipient may be carriers for. US banks who perform ECS include these results with a donor profile; some banks exclude carriers of more common recessive disease, while others accept all donors regardless of carrier status. Results from the US sperm bank indicated that of 1742 prospective donors who had ECS, only 117 (6.7%) of carriers would have been reported if screening under minimal guidelines. 665 of the 782 US positive carrier donors would not have been identified as carriers if tested according to UK guidelines. This, together with the observed varying regulation and commercial ECS panels used by donor banks internationally, demonstrate a tiered system of information availability and sharing for reproductive risk knowledge for donors and recipients; recipients are not consistently informed of the limitations of screening of a selected donor, and acceptance of donors to programs is inconsistent. Limitations, reasons for caution The panel composition and number of genes are variable by commercial ECS provider and donor banks may vary their carrier screening policy or commercial ECS options over time. Additionally, other European countries may have differing recommendations in regards to carrier screening practices. Wider implications of the findings As donor sperm imports from within and outside Europe increase, registered donors within countries will present differing genetic risk. Review and implementation of current carrier screening guidelines are required to ensure consistency of methodology and availability of transparent information for donors, recipients, and clinics to consider the wider implications. Trial registration number not applicable

The longevity-associated BPIFB4 gene guarantees vascular homeostasis and immune protection through platelets.

Beyond their activity in hemostasis and thrombosis, recent advances attribute platelets a pro-youthful role capable to attenuate immune senescence and age-related neuroinflammation. Previous studies from our group associated a polymorphic haplotype variant in the BPIFB4 gene (LAV-BPIFB4) with exceptional longevity. Transfer of the LAV-BPIFB4 in preclinical models has proved strategic to cope with frailty conditions, aging-related events, e.g., cardiovascular ones, and immune dysfunction mainly through a favorable conditioning of the immune system. However, whether platelets participate in LAV-BPIFB4 therapeutic action is currently unknown.Herein, we discovered that platelets were instrumental in boosting the favorable health outcomes of the systemic AAV-LAV-BPIFB4 gene transfer in vivo, as the α-CD42b platelet depletion completely abolished the vascular protective action of LAV-BPIFB4 and suppressed its pro-resolutive CD206 + anti-/CD86 + pro-inflammatory Ly6C + monocyte skewing to LPS stimulation. Of note, this is associated with a huge drop in the protective levels of BPIFB4 in the plasma of AAV-LAV-BPIFB4-injected C57BL/6 mice, indicating that plasma circulating platelets may be a reservoir of the BPIFB4 protein. Indeed, we noticed that BPIFB4 was released by human platelets, a process that is amplified in LAV-allele carrier donors. Accordingly, lentivirus-mediated overexpression of human LAV-BPIFB4 isoform, but not WT-BPIFB4 isoform was able in leading differentiated megakaryocytes to release more platelet-like-particles enriched for BPIFB4. In addition, in vitro, the M2 macrophage polarization increased when releasate from platelets, and even more from LAV pre-stimulated once, was added in monocyte cell culture. Our data suggest that platelet release of BPIFB4 and of yet-to-be-determined unidentified factors mediates the therapeutic efficacy of LAV-BPIFB4 treatment.

Oxygen vacancy-activated thermoelectric properties of ZnO ceramics

Understanding the structural and thermoelectric (TE) properties of a pure material is essential for developing a practical approach to improve its TE performance. This study focuses on the high-temperature TE properties of ZnO ceramics synthesized by the spark plasma sintering (SPS) technique. The analyses of crystallinity and microstructure along with photoluminescence and Raman spectroscopy indicated an increase in oxygen vacancy in the ZnO ceramics with SPS temperature, which resulted in unit-cell shrinkage, lattice modification, grain densification, and TE modification. Specifically, oxygen vacancies were found to be a crucial factor affecting the TE performance of the spark-plasma-sintered ZnO ceramics at temperatures exceeding 773 K. Oxygen vacancies can act as carrier donors when they are ionized, contributing to an increase in electrical conductivity and a decrease in thermal conductivity. Additionally, this study proposes a potential way to engineer native defects in ZnO ceramics by controlling the SPS process.

Self-healable, mechanically durable and cold-resistant integrated supercapacitor enabled by dual metallic redox-mediated multiple cross-linking gel polymer electrolyte

Flexible supercapacitor is an important energy supply source for wearable electronic devices. Herein, an integrated supercapacitor with exceptional electrochemical performance is successfully constructed based on a novel dual redox-mediated double network (DN) gel polymer electrolyte (GPE). Thanks to the synergistic effect of DN structure and multiple physical interactions (hydrophobic association, hydrogen bond and ionic coordination), the polyacrylic acid/lauryl methacrylate/sodium carboxymethyl cellulose/H2SO4/CuSO4_FeSO4 GPE possesses exceptional mechanical properties and rapid self-healing ability. In addition to being ionic cross-linking agents, CuSO4_FeSO4 can also serve as carrier donors and anti-freezing agents, endowing the GPE with excellent conductivity (0.17 S/cm) and low temperature adaptability. The GPE-based integrated supercapacitor demonstrates an outstanding specific capacitance of 414.96 mF/cm2 and a high energy density of 84.21 μWh/cm2, benefiting from redox reactions of Cu2+/Cu+ and Fe2+/Fe3+ at the electrode/electrolyte interface. Due to the seamless gradient structure, the interfacial resistance is reduced and the relative slippage is overcome, resulting in splendid capacitance retention of the supercapacitor under various mechanical deformations. Moreover, the device demonstrates promising self-healing ability even at −20 °C. This work provides a novel strategy for designing and fabricating the supercapacitor with self-healing, arbitrary deformability and anti-freezing in next-generation electronic devices.

Anesthesia management protocol for liver transplantation as treatment for ornithine transcarbamylase deficiency.

Ornithine transcarbamylase deficiency is an X-linked genetic disorder that induces accumulation of ammonia in the liver and is the most common urea cycle disorder. The clinical manifestation of ornithine transcarbamylase deficiency is hyperammonemia that causes irreversible neurological damage. Liver transplantation is a curative therapy for ornithine transcarbamylase deficiency. The aim of this study is to suggest, from our previous experience, an anesthesia management protocol of liver transplantation for ornithine transcarbamylase deficiency, particularly focused on liver transplantation for cases with uncontrolled hyperammonemia. We retrospectively reviewed our anesthesia-related experience in all cases of liver transplantation for ornithine transcarbamylase deficiency in our center. Twenty-nine liver transplantation cases for ornithine transcarbamylase deficiency were found between November 2005 and March 2021 in our center. Of these, 25 cases were stable through the perioperative period. However, 2 cases with carrier donor graft had hyperammonemia after liver transplantation. Another two cases had uncontrolled hyperammonemia before liver transplantation, even with continuous hemodialysis. They underwent life-saving liver transplantation. Their metabolic status stabilized after the anhepatic phase. Liver transplantation for cases with uncontrolled hyperammonemia can be performed with proper management. Second, liver transplantation with carrier donors should be avoided because of the risk of postoperative recurrence.

Stratified Oxygen Vacancies Enhance the Performance of Mesoporous TiO2 Electron Transport Layer in Printable Perovskite Solar Cells.

The low electrical conductivity and the high surface defect density of the TiO2 electron transport layer (ETL) limit the power conversion efficiency (PCE) of corresponding perovskite solar cells (PSCs). Here, the conductivity and defect modulation of the mesoporous TiO2 (mp-TiO2 ) ETL via oxygen vacancy (OV) management by the reduction and oxidation treatment are reported. Reduction treatment via reducing agent introduces abundant OVs into the TiO2 nanocrystalline particles on the surface and at the subsurface. The following oxidation treatment via hydrogen peroxide removes the surface OVs while remains the subsurface OVs, resulting in stratified OVs. The stratified OVs improve the conductivity of TiO2 ETL by increasing carrier donors and decrease nonradiative centers by reducing surface defects. Such synergy ensures the capability of mp-TiO2 as the well-performed ETL with improved energy level alignment, suppressed interface recombination, enhanced carrier extraction, and transport. As a result, printable hole-conductor-free carbon-based mesoscopic PSCs based on the modulated mp-TiO2 ETL demonstrate a highest reported PCE of 18.96%.

Directional Carrier Transport in Micrometer-Thick Gallium Oxide Films for High-Performance Deep-Ultraviolet Photodetection.

Incorporating emerging ultrawide bandgap semiconductors with a metal-semiconductor-metal (MSM) architecture is highly desired for deep-ultraviolet (DUV) photodetection. However, synthesis-induced defects in semiconductors complicate the rational design of MSM DUV photodetectors due to their dual role as carrier donors and trap centers, leading to a commonly observed trade-off between responsivity and response time. Here, we demonstrate a simultaneous improvement of these two parameters in ε-Ga2O3 MSM photodetectors by establishing a low-defect diffusion barrier for directional carrier transport. Specifically, using a micrometer thickness far exceeding its effective light absorption depth, the ε-Ga2O3 MSM photodetector achieves over 18-fold enhancement of responsivity and simultaneous reduction of the response time, which exhibits a state-of-the-art photo-to-dark current ratio near 108, a superior responsivity of >1300 A/W, an ultrahigh detectivity of >1016 Jones, and a decay time of 123 ms. Combined depth-profile spectroscopic and microscopic analysis reveals the existence of a broad defective region near the lattice-mismatched interface followed by a more defect-free dark region, while the latter one serves as a diffusion barrier to assist frontward carrier transport for substantially enhancing the photodetector performance. This work reveals the critical role of the semiconductor defect profile in tuning carrier transport for fabricating high-performance MSM DUV photodetectors.

A Kinetic Model for the Generation and Annihilation of Thermally Induced Carrier Donors in a Semiconducting Metal‐Oxide Thin Film (Small 41/2022)

A Kinetic Model for the Generation and Annihilation of Thermally Induced Carrier Donors in a Semiconducting Metal‐Oxide Thin Film (Small 41/2022)

A Kinetic Model for the Generation and Annihilation of Thermally Induced Carrier Donors in a Semiconducting Metal-Oxide Thin Film.

Based on a kinetic model involving oxidant diffusion and an oxidation-reduction reaction, a 3-parameter equation is derived relating the change in the concentration of thermally induced carrier donors in common metal-oxide semiconductors (such as indium-gallium-zinc oxide and indium-tin-zinc oxide) to heat-treatment time. The change in the concentration of such donors is characterized by measuring the shift in the turn-on voltage of a thin-film transistor subjected to heat treatments in different atmospheres for different durations. The model parameters are extracted using optimal curve-fitting techniques, leading to the determination of relevant activation energies from the temperature dependence of the extracted parameters. The proposed model is found to be applicable to metal-oxide semiconductors of different compositions. It is discovered that the generation of donors in a non-oxidizing atmosphere is largely suppressed at a temperature below 250°C, but the effective annihilation of the donors spans over a wider temperature range in an oxidizing atmosphere.

Sandwiched Graphene/Bi2Te3/Graphene Thermoelectric Film with Exceptional Figure of Merit for Flexibility

AbstractFlexible thermoelectrics (TEs) that fit curved human skin well, could harvest energy from skin, and thus have been considered as a promising portable power source for wearable electronics. Bi2Te3, the most popular room‐temperature TE material, is still challenging to be applied in flexible devices due to its rigid nature. Although many Bi2Te3‐based films have been reported to be flexible when made thin enough, the thermal and electrical loads across them are rather small with severe limitation on the maximum power output. This work realizes a thick Bi2Te3‐based TE film with a “graphene/Bi2Te3/graphene” sandwiched structure, which demonstrates an unprecedentedly high figure of merit for flexibility among all Bi2Te3‐based films ever reported, due to the outstanding intrinsic flexibility of graphene and a small slippage barrier. Meanwhile, graphene acts as express conducting channels as well as carrier donors, resulting in an increased electrical conductivity. The numerous graphene/Bi2Te3 heterointerfaces induce energy filtering effect, leading to an enhanced Seebeck coefficient, and thus an optimized power factor is achieved. This work offers a cost‐effective avenue to make highly flexible TE films for power supply of wearable electronics by intercalating TE nanoplates into 2‐dimensional nanosheets.

HSCT using carrier donors for CD40L deficiency results in excellent immune function and higher CD40L expression in cTfh

AbstractData are limited regarding the immune status of CD40 ligand (CD40L)–deficient carriers and hematopoietic stem cell transplantation (HSCT) outcomes using them as donors for CD40L-deficient patients. Therefore, we studied the immune profiles of 7 carriers, 4 of whom were HSCT donors for family members with CD40L deficiency, and we characterized their HSCT outcomes. Immunoglobulin profiles, CD4, CD8, circulating T-follicular helper (cTfh) cells, and regulatory T cells (Tregs) in carriers were comparable to those in healthy controls. CD40L expression in carriers ranged from 37% to 78%. cTfh cells from carriers expressed higher CD40L compared with total CD4 cells or the memory CD4 compartment, suggesting a potential advantage to CD40L-expressing cTfh cells. Tregs had minimal CD40L expression in carriers and healthy controls. So we postulated that HSCT using donors who were CD40L carriers may result in excellent immune reconstitution without immune dysregulation. Four CD40L-deficient patients underwent HSCT from carriers who had CD40L expression from 37% to 63%. All patients engrafted, achieved excellent immune reconstitution with lack of opportunistic infections, graft-versus-host disease, and immune dysregulation; stable CD40L expression mimicked that of donors 1 to 5 years after HSCT. Immunoglobulin independence was achieved in 3 of the 4 patients. We demonstrated higher CD40L expression in the cTfh compartment of carriers and excellent immune reconstitution using donors who were CD40L carriers in CD40L-deficient patients.

Therapeutic potential of living donor liver transplantation from heterozygous carrier donors in children with propionic acidemia

BackgroundCurrent world experience regarding living donor liver transplantation (LDLT) in the treatment of propionic acidemia (PA) is limited, especially in terms of using obligate heterozygous carriers as donors. This study aimed to evaluate the clinical outcomes of LDLT in children with PA.MethodsFrom November 2017 to January 2020, 7 of the 192 children who underwent LDLT at our institution had been diagnosed with PA (median age, 2.1 years; range, 1.1–5.8 years). The primary indication for transplantation was frequent metabolic decompensations in 6 patients and preventative treatment in 1 patient. Of the seven parental living donors, six were genetically proven obligate heterozygous carriers.ResultsDuring a median follow-up of 23.9 months (range, 13.9–40.2 months), all patients were alive with 100% allograft survival, and no severe transplant-related complications occurred. In the case of liberalized protein intake, they did not suffer metabolic decompensation or disease-related complications and made progress in neurodevelopmental delay and body growth, as well as blood and urinary metabolite levels. In one patient with pre-existing mild dilated cardiomyopathy, her echocardiogram results completely normalized 13.8 months post-transplant. All living donors recovered well after surgery, with no metabolic decompensations or procedure-related complications. Western blotting revealed that the hepatic expressions of PCCA and PCCB in one of the heterozygous donors were comparable to those of the normal healthy control at the protein level.ConclusionsLDLT using partial liver grafts from asymptomatic obligate heterozygous carrier donors is a viable therapeutic option for selected PA patients, with no negative impact on donors’ and recipients' clinical courses.

Outcomes After Living Donor Liver Transplantation in Pediatric Patients with Inherited Metabolic Diseases.

BackgroundThere is no consensus about the long-term prognosis of pediatric patients with a variety of rare liver diseases but with inherited metabolic diseases (IMDs). We retrospectively reviewed the developmental outcomes of patients with IMDs undergoing living donor liver transplantation (LDLT).Material/MethodsBetween May 2001 and December 2020, of 314 pediatric patients who underwent LDLT, 44 (14%) had IMDs. The median age at LDLT was 3.0 years old (range 0–15.0 years). Associations between the post-transplant complications and graft survival rate in patients with IMDs and biliary atresia (BA) were calculated. We evaluated the safety of LDLT from heterozygous carrier donors, the prognosis of patients with IMDs who have metabolic defects expressed in other organs, and developmental outcomes of patients with IMDs.ResultsThe 10-year graft survival rates in patients with IMDs and BA were 87% and 94%, respectively (P=0.041), and the causes of graft failure included pneumocystis pneumonia, acute lung failure, hemophagocytic syndrome, hepatic vein thrombosis, portal vein thrombosis, and sepsis. The rate of post-transplant cytomegalovirus viremia in patients with IMDs was higher than that of patients with BA (P=0.039). Of 39 patients with IMDs, 15 patients (38%) had severe motor and intellectual disabilities in 4 patients, intellectual developmental disorders including epilepsy in 2, and attention-deficit hyperactivity disorder in 2. Of 28 patients with IMDs, 13 (46%) needed special education.ConclusionsThe long-term outcomes of LDLT in patients with IMDs are good. However, further long-term social and educational follow-up regarding intellectual developmental disorders is needed.

Screening of rice gene pool for resistance to pyriculariosis by phenotyping and DNA genotyping

When creating new resistant varieties of rice of an intensive type, an important aspect of the breeding process is the study of the diversity of cultural genetic resources. In the Krasnodar Territory, in Russia and in the world as a whole, the most harmful and common rice disease is pyricularosis (Pyricularia oryzae Br.et Cav.). The aim of this work was to study the genetic diversity accumulated in the collection of the rice institute (ARRRI, Krasnodar city) for the resistance to the causative agent of pyriculariosis to create a new source material with genes for a wide spectrum of resistance. In the course of studies, the results of phenotypic (1337 samples), immunological (775 samples) and molecular screening (115 samples) of the gene pool of Oryza sativa L. were obtained for the resistance to the pathogen of pyriculariosis. The rate of development of the disease (RDD,%) over the years of testing the general plasma varied within 5.6-85.0%. The proportion of varieties medium resistant to the fungus M. Grisea was significantly higher in almost all countries except Italy and Brazil, where the number of resistant forms was at the level of medium resistant. In the general plasma of Bulgaria, Uruguay, Greece, India and African countries, stable forms were generally absent. The world variety of rice genotypes showing resistance to the local pathogen population has been shown. Screening of the rice gene pool for the presence of the Pi-9 and Pi-k genes made it possible not only to identify carrier donors, but also to establish their frequency of occurrence in the global general plasma. Against a provocative background, the identification of effective resistance genes was carried out using monogenic differentiator lines of Pyricularia oryzae races, 15 resistance genes were isolated.

Oxygen vacancy induced strong anisotropy of the thermoelectric properties of strontium barium niobate

Electronic structure and thermoelectric properties of strontium barium niobate were investigated by first principles calculations combined with the semi-classical Boltzmann theory. The band structure corresponding to lattice anisotropy shows higher band dispersion along c axis, but the conductive pathway is mainly along ab plane. As a result, the values of power factor are in the same order of magnitude along different directions. Thus, the lattice anisotropy alone cannot result in the strong anisotropic thermoelectric properties of strontium barium niobate. Oxygen vacancies not only act as charge carrier donors, but also enhance the band dispersion and change the magnetic quantum number of the electrons around the bottom of conduction band. Accordingly, the thermoelectric properties of strontium barium niobate show very strong anisotropy after oxygen reduction.

Effects of potassium interstitial doping on thermoelectric properties of Sr0.7Ba0.3Nb2O6−δ ceramics

The thermoelectric properties of potassium interstitial doped Sr0.7Ba0.3KxNb2O6−δ ceramics were investigated in the temperature range from 323 to 1073 K. The thermoelectric power factor is improved enormously due to the potassium interstitial doping combined with a reductive calcination method. The potassium dopants not only act as carrier donors but also modulate the electronic structures. Thus, the electrical conductivity increases remarkably, and the Seebeck coefficient, meanwhile, maintains considerable values at high temperatures. Only the moderate doping content x = 0.10 contributes to reducing the lattice thermal conductivity. Thus, the sample Sr0.7Ba0.3K0.1Nb2O6−δ shows the highest ZT value of 0.23 at 1073 K.

Sex-specific survival difference in association with HLA-DRB1∗04 following allogeneic haematopoietic stem cell transplantation for lymphoid malignancies

The role of HLA system in allogeneic haematopoietic stem cell transplantation (allo-HSCT) outcome is unarguable. In this study we investigated association of HLA-A,-B and-DRB1 alleles with overall survival (OS) in 186 patients undergoing allo-HSCT for lymphoid malignancies. Analyses confirmed significantly better OS for HLA-DRB1∗04 carriers compared with non-carriers (p = 0.01). Survival benefit was confined to male patients (in multivariate analyses p = 0.034, hazard ratio 0.35, 95% confidence interval 0.13–0.92), whereas in females no difference was noted (p = 0.82). Furthermore, donor gender also affected outcome and transplantation from female HLA-DRB1∗04 carrier donors resulted in superior survival compared with female non-carrier donors (p = 0.01). Combined analyses including recipient/donor gender and HLA-DRB1∗04 showed that survival of male patients varied significantly according to donor gender and HLA-DRB1∗04 carriership (p = 0.04) with best survival among HLA-DRB1∗04 carriers transplanted from female donors. Of relevance to our results, HLA-DRB1∗04 has been documented as risk allele group for lymphoid malignancies, and studies described a male-specific risk. We believe that our findings provide further supporting evidence for sex-specific alterations secondary to HLA-DRB1∗04 or related genes. Further studies are warranted to evaluate whether in contrast to general favour of male donors HLA-DRB1∗04 carrier patients with lymphoid malignancies could benefit from transplantation from female donors.

Splicing arrays reveal novel RBM10 targets, including SMN2 pre-mRNA

BackgroundRBM10 is an RNA binding protein involved in message stabilization and alternative splicing regulation. The objective of the research described herein was to identify novel targets of RBM10-regulated splicing. To accomplish this, we downregulated RBM10 in human cell lines, using small interfering RNAs, then monitored alternative splicing, using a reverse transcription-PCR screening platform.ResultsRBM10 knockdown (KD) provoked alterations in splicing events in 10–20% of the pre-mRNAs, most of which had not been previously identified as RBM10 targets. Hierarchical clustering of the genes affected by RBM10 KD revealed good conservation of alternative exon inclusion or exclusion across cell lines. Pathway annotation showed RAS signaling to be most affected by RBM10 KD. Of particular interest was the finding that splicing of SMN pre-mRNA, encoding the survival of motor neuron (SMN) protein, was influenced by RBM10 KD. Inhibition of RBM10 resulted in preferential expression of the full-length, exon 7 retaining, SMN transcript in four cancer cell lines and one normal skin fibroblast cell line. SMN protein is expressed from two genes, SMN1 and SMN2, but the SMN1 gene is homozygously disrupted in people with spinal muscular atrophy; as a consequence, all of the SMN that is expressed in people with this disease is from the SMN2 gene. Expression analyses using primary fibroblasts from control, carrier and spinal muscle atrophy donors demonstrated that RBM10 KD resulted in preferential expression of the full-length, exon 7 retaining, SMN2 transcript. At the protein level, upregulation of the full-length SMN2 was also observed. Re-expression of RBM10, in a stable RBM10 KD cancer cell line, correlated with a reversion of the KD effect, demonstrating specificity.ConclusionOur work has not only expanded the number of pre-mRNA targets for RBM10, but identified RBM10 as a novel regulator of SMN2 alternative inclusion.

The effect of charge carrier and doping site on thermoelectric properties of Mg2Sn0.75Ge0.25

Mg2Sn0.75Ge0.25 has been recently demonstrated to be a promising thermoelectric material for power generation in the temperature range from room temperature to 723 K because of the high power factor of ∼54 μW cm−1 K−2 upon Sb doping to the Sn site. The enhanced density of states effective mass and weak electron scattering from the alloying effect are believed to be the main reasons for the high power factor (PF) and hence high figure of merit (ZT). In this study, it is shown that the right choice of carrier donor also plays an important role in obtaining high power factor. The effect of carrier donors Y and La at Mg-site and Bi and P at Sn-site in Mg2Sn0.75Ge0.25 is systematically investigated. It is found that charge donors at the Sn-site are much more effective than at the Mg-site in enhancing PF and ZT. Bi doped Mg2Sn0.73Bi0.02Ge0.25 shows a peak ZT of ∼1.4 at 673 K, a peak PF of ∼54 μW cm−1 K−2 at 577 K, which resulted in an engineering figure of merit (ZT)eng of ∼0.76 and (PF)eng of ∼2.05 W m−1 K−1 for cold side fixed at 323 K and hot side at 723 K.

Quantitative structure-property relationship model leading to virtual screening of fullerene derivatives: Exploring structural attributes critical for photoconversion efficiency of polymer solar cell acceptors

The power conversion efficiency (PCE) of pure polymer solar cells (PSCs) remains low, although significantly higher values could be achieved by using PSCs as carrier donors in conjunction with composite fullerene derivative (FD) acceptors. Significant resources, however, are required to experimentally develop and screen FDs that may serve as efficient acceptors in PSCs. Often, the materials are expensive, the methods are time consuming, and the production processes can generate toxic hazards. As an alternative approach, we introduce a quantitative structure-property relationship (QSPR) model for predicting the PCE of 59 FDs, including both C60 and C70 FDs. The QSPR model enables identification of the essential structural attributes necessary for quantifying the molecular prerequisites of diverse FDs, chiefly responsible for high PCE of PSC acceptors in composition with poly(3-hexylthiophene) (P3HT). The identified properties and structural fragments are particularly valuable for guiding future synthetic efforts for development of FDs with improved power conversion efficiency. Furthermore, a large number of FDs are collected to generate a database. Virtual screening of the database employing the developed QSPR model allows for identification of nine FDs with higher PCE than previously studied FDs.