Small Donor Research Articles

Fluorination or Not in Small Molecule Solar Cells: Achieving a Higher Efficiency with Halogen-Free End Group.

Fluorination is an efficient strategy for improving organic solar cells (OSCs) efficiency, particularly by fluorinating the end group of emerging nonfullerene acceptors. Here, the fluorination effect was investigated by using small molecule donors with fluorine-free (SBz) and fluorinated (SBz-F) end groups, paired with the emerging nonfullerene acceptor Y6. Interestingly and unexpectedly, fluorination of the end group negatively affects OSCs efficiency, with fluorine-free SBz:Y6 OSCs achieving a higher power conversion efficiency (PCE) of 11.05 % compared to the fluorine-containing SBz-F:Y6 blends (PCE=9.61 %). Analysis of space-charge limited currents reveals lower and unbalanced hole/electron mobility in SBz-F:Y6 compared to the SBz:Y6 blends. These findings are further supported by charge recombination dynamics and donor-acceptor miscibility analyses.

Sequential Release of Ibuprofen and the Gasotransmitter Hydrogen sulfide using Oxanorbornane-Based Synthetic Lipids as Carriers.

After understanding the biological signaling roles of hydrogen sulfide and its involvement in various physiological processes, there has been enormous interest in exploring its therapeutic utility in areas such as cancer, inflammation, cardiovascular diseases, etc. There is also growing interest in using suitable H2S donors in combination with other drugs to improve the treatment outcome through the modulation of multiple pathways. The premature release of H2S from small molecule donors and the difficulty in controlling its spatio-temporal distribution are the major challenges during these efforts. Hence the development of appropriate carriers that can release this gasotransmitter along with the therapeutic entity of interest in a controlled manner has high significance. In this regard, this report presents a novel drug delivery system from oxanorbornane-based synthetic lipids that carries a H2S-releasing 1,2-dithiole-3-thione moiety as part of the head group. Nanoaggregates of the resulting conjugate are not only capable of efficiently entrapping a non-steroidal anti-inflammatory drug such as ibuprofen, but also release this drug and H2S in a controlled and sequential manner.

Senior Discount? Gender, Age, and Small Donor Fundraising

Recent discussions surrounding candidate age and its impact on small donor fundraising have raised questions about ageism in American politics. However, existing studies of age in politics largely neglect the specific obstacles encountered by older female candidates. This paper, which examines the impact of age and gender on small contribution receipts in U.S. House of Representatives campaigns from 2006-2010, aims to address the following questions: How do age and gender interact to predict small contribution receipts? What are the implications for fundraising of older women candidates compared to their male counterparts? The findings reveal a significant negative interaction between age and gender, indicating that older female candidates experience a pronounced reduction in small contribution receipts compared to older male candidates. This suggests that age-related biases intersect with gender, posing unique challenges for older women candidates in fundraising efforts.

Impact of Different π-Bridges on the Photovoltaic Performance of A-D-D'-D-A Small Molecule-Based Donors.

Three small donor molecule materials (S1, S2, S3) based on dithiophene [2,3-d:2',3'-d']dithiophene [1,2-b:4,5-b']dithiophene (DTBDT) utilized in this study were synthesized using the Vilsmeier-Haack reaction, traditional Stille coupling, and Knoevenagel condensation. Then, a variety of characterization methods were applied to study the differences in optical properties and photovoltaic devices among the three. By synthesizing S2 using a thiophene π-bridge based on S1, the blue shift in ultraviolet absorption can be enhanced, the band gap and energy level can be reduced, the open circuit voltage (VOC) can be increased to 0.75 V using the S2:Y6 device, and a power conversion efficiency (PCE) of 3% can be achieved. Also, after developing the device using Y6, S3 introduced the alkyl chain of thiophene π-bridge to S2, which improved the solubility of tiny donor molecules, achieved the maximum short-circuit current (JSC = 10.59 mA/cm2), filling factor (FF = 49.72%), and PCE (4.25%). Thus, a viable option for future design and synthesis of small donor molecule materials is to incorporate thiophene π-bridges into these materials, along with alkyl chains, in order to enhance the device's morphology and charge transfer behavior.

The surge of the small donorate in U.S. elections: A view from Texas statewide campaigns

Over the last twenty years, a remarkable surge in small donor contributing has been observed throughout the United States. Little is known, however, about the geographic origin of these small donors. In this research, we ask whether the impressive emergence of small donors is observed in the same places the large donations spring from, or whether these donors occupy a distinct, more dispersed, geography. If the new donors are emerging from locations where donations are traditionally scarce, then perhaps this extraordinary development is more politically significant. We find that small donor fundraising has had a centrifugal impact on the campaign playing field, bringing fundraising into closer congruence with other grassroots outreach efforts. The democratization of campaign finance is well underway with observers now engaged in a vigorous debate about the consequences.

Small Donors, Big Impact: Optimizing Organ Utilization in Simultaneous Pancreas and Kidney Transplantation From Extra Small Pediatric Donors.

Simultaneous pancreas-kidney transplantation (SPK) is the preferred treatment for individuals with type-1 diabetes and end-stage renal disease. However, a limited supply of "Ideal Pancreas Donors" contributed to a growing disparity between available organs and recipients. Even though SPK outcomes from pediatric donors match those from adult donors, unclear guidelines on minimum age and weight criteria for extra small pediatric pancreas donors lead to hesitancy among several transplant centers to utilize these grafts due to concerns about inadequate islet mass, technical challenges, and increased risk of allograft thrombosis. This report details the successful outcomes of SPK transplantations performed at the study center between December 2021 and January 2024, using four extra small pediatric brain-dead donors (ESPDs). Each donor was aged ≤5 years and weighed <20kg. All SPK recipients achieved immediate posttransplant euglycemia without requiring insulin. None of the recipients experienced graft pancreatitis, graft thrombosis, allograft rejection, or required re-exploration. During a 5-27-month follow-up period, all ESPD recipients maintained optimal graft function, as evidenced by normal glucose tolerance tests and HbA1c (4.9%-5.2%), with 100% graft and patient survival. This report examines the usage of ESPDs in SPK transplantation, highlighting their potential to expand the donor pool and reduce wait times in areas with scarce deceased organ donations, thereby increasing the number of available organs for transplantation with acceptable outcomes. Revising donor selection guidelines to reflect the diverse risk-benefit profiles of waitlisted individuals is crucial to addressing geographical disparities and reducing organ discard rates.

P.285: Simultaneous pancreas and kidney transplantation from a small pediatric donor with ipsilateral implantation over aortic cuff.

P.285: Simultaneous pancreas and kidney transplantation from a small pediatric donor with ipsilateral implantation over aortic cuff.

Preparation and performance study of organic small molecule photovoltaic donor materials in solar cells

Abstract In this study, PDPAT-BDT-BT was used as a donor material, combined with PC61BM and PC71BM as acceptor materials, to prepare a hybrid thin film for organic solar cells. In photovoltaic performance tests, this film shows advantages and good characteristics. The experimental results show that the PDPAT-BDT-BT polymer shows good performance in terms of thermal stability, optical properties, and electrochemical properties. It also shows better photovoltaic performance in the hybrid system with PC71BM, which lays a good foundation for its potential application in organic solar cells.

Political Inequality

Inequality in political participation and influence has strongly increased in recent decades, breeding economic inequality. In this review, we focus on three aspects of political inequality: the increasing concentration of both political and charitable donations, the growing gap in descriptive representation, and the persistent lack of substantive representation. Based on the existing literature as well as on novel evidence, we relate these aspects to the recent widening of turnout inequality. We then examine novel forms of participation—e.g., the rise of small donors in the United States—and the efficiency of policies aimed at improving representation. Finally, we discuss new avenues for research.

Recent Advancements in Polymeric N-Nitrosamine-Based Nitric Oxide (NO) Donors and their Therapeutic Applications.

Nitric oxide (NO), a gasotransmitter, is known for its wide range of effects in vasodilation, cardiac relaxation, and angiogenesis. This diatomic free radical also plays a pivotal role in reducing the risk of platelet aggregation and thrombosis. Furthermore, NO demonstrates promising potential in cancer therapy as well as in antibacterial and antibiofilm activities at higher concentrations. To leverage their biomedical activities, numerous NO donors have been developed. Among these, N-nitrosamines are emerging as a notable class, capable of releasing NO under suitable photoirradiation and finding a broad range of therapeutic applications. This review discusses the design, synthesis, and biological applications of polymeric N-nitrosamines, highlighting their advantages over small molecular NO donors in terms of stability, NO payload, and target-specific delivery. Additionally, various small-molecule N-nitrosamines are explored to provide a comprehensive overview of this burgeoning field. We anticipate that this review will aid in developing next-generation polymeric N-nitrosamines with improved physicochemical properties.

Enhancing D/A Interactions via Porphyrin Isomerization to Improve Photovoltaic Performance.

The interactions between the electron donors and electron acceptors (D/A) play important roles for the performance of organic solar cells (OSCs).While the isomerization strategy is known to optimize molecular geometries and properties, the impacts of isomerization on the donors or acceptors in D/A interactions have not been extensively investigated.Here in, we innovatively investigated the impacts of donor isomerism on the D/A interactions by synthesizing two small molecule donors m-ph-ZnP2and p-ph-ZnP2by linking two functionalized porphyrins at the meta and para positions of phenyl groups, respectively.Compared with p-ph-ZnP2, m-ph-ZnP2displays reduced self-aggregation but with PC61BM.Consequently, a much higher power conversion efficiency (PCE) of 5.43% is achieved for the m-ph-ZnP2binary OSCs than the p-ph-ZnP2devices with a PCE of 2.03%.The enhanced performance of m-ph-ZnP2-based device can be primarily attributed to the stronger intramolecular charge transfer (ICT), the enhanced D/A interactions, the improved charge transfer, and the suppressed charge recombination.Furthermore, the ternary devices based on m-ph-ZnP2:Y6:PC61BM achieve a PCE of 8.34%. In short, this work elucidates the relationship among the chemical structure, D/A interactions and device performance, providing valuable guidelines for designing efficient OSCs materials.

All‐Small‐Molecule Ternary Organic Solar Cell with 16.35% Efficiency Enabled by Chlorinated Terminal Units

In the last few years, there have been notable developments in organic solar cells using both small molecule donor and acceptor. It has been noted that adding halogens to the end groups of small molecules could enhance the film structure and, consequently, the performance of the devices. In this study, three novel small molecule donors are created. The molecules include a vinyl‐CPDT oligomer with three units, with end‐caps made up of indanedione groups and containing four H, four Cl, and four F substituents. The purpose of the study is to investigate how the halogen substituent affects the photovoltaic characteristics of binary devices made with the non‐fullerene acceptor (NFA) TOCR2 as the acceptor. Having the halogen in the device enhances its effectiveness, and FG5, which has 4‐Cl substituents in the end groups, shows the highest efficiency among all devices with a PCE of 14.39%. Incredibly, the ternary device that is created in normal atmospheric conditions with chloro‐substituted FG5 as the donor, TOCR2 as the acceptor, and the wide band gap NFA DICTF as the third element shows significantly improved efficiency, achieving PCE values of up to 16.35%.

Dimerized small molecule donor enables efficient ternary organic solar cells

Ternary organic solar cells (OSCs) are the feasible and efficient strategy to achieve the high-performance OSCs. It is of great significance to develop a superior third component candidate for constructing efficient ternary OSCs. In this work, we intelligently designed and synthesized a dimerized small molecule donor by connecting two asymmetric small molecule donors with the vinyl group, which is named DSMD-βV. This innovative oligomeric molecule DSMD-βV not only exhibits the complementary absorption and the cascade energy level arrangement with PM6 and BTP-eC9, but also regulates the phase separation micromorphology based on PM6:BTP-eC9. Consequently, PM6:DSMD-βV:BTP-eC9 based ternary device exhibits the improved exciton dissociation, charge transport and decreased recombination, thus achieving a superior power conversion efficiency (PCE) of 18.26 %, surpassing PM6:BTP-eC9 based binary (17.63 %). This work indicates that the dimerized small molecule donor is able to become a promising third component candidate, which also opens up a unique idea for the construction of efficient ternary organic solar cells.

Double-bridged N–B←N bipyridyl-based airfoil-shaped small molecule dyes: π-bridge regulation on photovoltaic performance

The double-bridged N–B←N bipyridine unit (BNBP) with boron-nitrogen covalent bond and coordination bond can reduce the electronic energy level of the π-conjugated system, resulting in a reduction of band gap and a red shift in the absorption spectrum. Embedding the BNBP building block into organic optoelectronic materials provides a novel possibility in molecule design. In this paper, under the guidance of density functional theory (DFT) calculations, a series of 3D “airfoil-shaped” small molecule donors (SMDs) have been designed and successfully synthesized through Sonogashira, Suzuki and Stille coupling reactions. BNBP is adopted as the central electron-withdrawing unit and strong electron-rich triphenylamine (TPA) as the terminal group. The novel “airfoil-shaped” structure plays a supporting role in reducing the carrier recombination in the active layer. It reveals that molecular design engineering can achieve the expected results by the following steps: Firstly, the introduction of electron-rich alkoxy groups into the end of TPA through side chain engineering helps to improve the solubility and film-forming properties of the materials. Then, the π-bridge regulation not only extends the conjugate structure, but also plays a crucial role in the regulation of photovoltaic properties. It is worth noting that the compound BNBP(3TTPA)2 was synthesized by introducing thiophene oligomer into BNBP-based SMDs for the first time. Finally, the compound BNBP(EDPPTPA)2 was constructed by combining BNBP with DPP dye unit. Its narrow band gap is only 1.36 eV, which is one of the narrowest band gaps in small molecular organic-boron materials. In particular, compared with the starting compound BNBP(ETPA)2, the synergistic effects of DPP and BNBP broaden the edge absorption wavelength to 814 nm, resulting in a red shift of 170 nm. The power conversion efficiency (PCE) of 4.48 % is obtained in BNBP(EDPPTPA)2-based bulk heterojunction (BHJ) organic solar cells (OSCs), which is more than twice that of reference compound BNBP(ETPA)2. This work provides important references for the future development of 3D BNBP-based organic-boron SMDs and the structural regulation of materials through molecular engineering.

Molecular engineering strategy and optoelectronic properties of diaminobenzene-thiazole π-conjugated small donor molecules for high-performance organic solar cells

In this current study, the π-conjugated oligomers based on Thiazole units have been designed to understand the interaction of molecular orbitals and the influence of the substituents on the energetic HOMO-LUMO gap to build highly π-conjugated nanostructures. Their strong π-conjugated insight was also evidenced in gas phase through the photovoltaic properties using B3LYP/6-31G(d,p) level of theory for potential applications in organic electronic devices. Our research indicates geometries optimized structures, FMOs and chemical parameters were determined to predict optical properties of all oligomers. The results demonstrate that thiazole unit’s addition improved absorption above 400 nm at first excited states. The open-cicruit voltage Voc have been decreased from 2.22 V to 1.26 V in M1-a to M1-d. Whereas, LHE values was increased from 0.404 to 0.986 in M2-a to M2-d. All designed molecules have shown the enhanced optoelectronic characteristic that is plausible reason for their potential photoactive use in Organic Photovoltaics (OPVs) devices efficiencies.

Terminal group engineering of oligothiophene donors for efficient organic solar cells

All-small-molecule organic solar cells exhibit high reproducibility than polymer-based cells. Benzodithiophene and oligothiophene based derivatives are the most widely studied small molecule donors. The lower synthetic complexity and superior stability make oligothiophene based derivatives more promising for large scale production. Recently, a thiazole-centered oligothiophene donor Tz6T yields a high efficiency but deserves further improving. Substitution of halogen atoms on the end groups is proven to affect molecular packing through various non-covalent intermolecular interactions. Here we adopt terminal group engineering to regulate the optoelectronic properties of Tz6T. Through chlorine substitution, highest efficiency (9.60 %) is achieved in Tz6T-PH-Cl-4: eC9-4F binary device. Our results shed light on the structure-function relationship, and provide valuable insights into the regulation of phase separation.

Free Flap Evaluation Following Reconstruction of Locally Advanced Squamous Cell Carcinoma of The Tongue

Background: Neoadjuvant chemotherapy (NAC) is a crucial component in the management of tongue-based locally advanced squamous cell carcinoma (LASCC) due to its ability to decrease tumor mass and facilitate free tissue transplantation. The utilization of adjuvant radiation and chemotherapy has been observed to decelerate the progression of post-operative tumor growth. Probability of free flap failure is elevated. Post-operative complications and the long-term functional outcomes of speaking, salivation, and swallowing determine the quality of free flaps. Methods: A retrospective review of tongue LASCC patients who underwent NAC followed by glossectomy and free tissue transfer from 2015 to 2018. Tongue functional outcomes of speaking, swallowing, and salivation were assessed using FACE-Q scale in 3 times follow-up period. Result: This study included 7 patients who underwent tongue reconstruction. Treatment modalities were based on tumor presentation, with 4 patients (57.1%) receiving Taxane, 5-Fluorouracil, and Paclitaxel/Doclitaxel (TPF), and 3 patients (42.1%) receiving Paclitaxel and 5-Fluorouracil (PF). Tongue reconstruction utilized the radial forearm free flap in 5 patients (71.4%) and the anterolateral thigh free flap in 2 patients (28.6%). Intraoperatively, NAC had no impact on the integrity of small and reliable donor vessels. Three patients died from tumor metastases after the second follow-up assessment, while one patient was lost to follow-up. The study found no significant association between chemotherapy dosage and free flap vitality (P = 0.629). FACE-Q assessments revealed moderate to low scores in speaking, eating, and drinking outcomes. Conclusion: Tongue reconstruction after NAC in LASCC patients remains a challenging procedure for surgeons. While the consideration of surgical difficulties due to damage of the donor vessels demands a more structured pre-operative plan. No correlation between the exposure of NAC or AR to free flap complication as well as functional outcome.

Combined application of artificial bone powders and concentrated growth factor membranes on the autotransplantation of mature third molars: A 5-year retrospective case series.

This study aimed to observe the efficacy and outcomes of the combined application of artificial bone powder and concentrated growth factor (CGF) membranes for tooth transplantation in cases with wide recipient sockets and small donor teeth. A total of 36 teeth from 36 patients with wide recipient sockets and small donor teeth were enrolled. Autogenous tooth transplantation was performed using bone powders and CGF membranes. After transplantation, the visual analog scale (VAS) score, Landry Wound Healing Index, probing depth (PD), mobility, and gray value of the alveolar bone around the transplanted teeth were measured, and a patient satisfaction questionnaire was administered. All patients underwent clinical and radiographic examinations during follow-up. The VAS score of 16 (44.4%) cases after 1 week was 0, and 26 (72.2%) patients showed excellent gingival healing after 2-4 weeks. The PD of a few cases was deeper than 3 mm during the first month; however, returned to normal after 3 months. Although the majority of the transplanted teeth possessed mobility greater than grade I during the first month, the mobility gradually improved within 3 months. The gray value of the alveolar bone around the transplanted teeth, 1 year postoperatively showed no difference with pre-operation (p > .05). During the mean follow-up period of 42.7 months (range 20-72 months), 33 of the 36 transplanted teeth remained insitu without clinical or radiographic complications, with an overall success rate of 91.7%. Although the PD and mobility of the transplanted teeth were not ideal during the early stages of healing, most of the transplanted teeth had good clinical outcomes. In cases with large recipient sites accompanied by small donor teeth, autotransplantation of teeth using artificial bone powder combined with CGF membranes is a viable option and can lead to optimistic results with favorable success rates.

Biofilm microenvironment-activated multimodal therapy nanoplatform for effective anti-bacterial treatment and wound healing

Antimicrobial drug development faces challenges from bacterial resistance, biofilms, and excessive inflammation. Here, we design an intelligent nanoplatform utilizing mesoporous silica nanoparticles doped with copper ions for loading copper sulfide (DM/Cu2+-CuS). The mesoporous silica doped with tetrasulfide bonds responds to the biofilm microenvironment (BME), releasing Cu2+ions, CuS along with hydrogen sulfide (H2S) gas. The release of hydrogen sulfide within 72 h reached 793.5 µM, significantly higher than that observed with conventional small molecule donors. H2S induces macrophages polarization towards the M2 phenotype, reducing inflammation and synergistically accelerating endothelial cell proliferation and migration with Cu2+ions. In addition, H2S disrupts extracellular DNA within biofilms, synergistically photothermal enhanced peroxidase-like activity of CuS to effectively eradicate biofilms. Remarkably, DM-mediated consumption of endogenous glutathione enhances the anti-biofilm activity of H2S and improves oxygen species (ROS) destruction efficiency. The combination of photothermal therapy (PTT), chemodynamic therapy (CDT), and gas treatment achieves sterilization rates of 99.3 % and 99.6 % against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli), respectively, in vitro under 808 nm laser irradiation. Additionally, in vivo experiments demonstrate a significant biosafety and antibacterial potential. In summary, the H2S donor developed in this study exhibits enhanced biocompatibility and controlled release properties. By integrating BME-responsive gas therapy with antibacterial ions, PTT and CDT, a synergistic multimodal strategy is proposed to offer new therapeutic approaches for wound healing. Statement of significanceThe advanced DMOS/Cu2+-CuS (DMCC) multimodal therapeutic nanoplatform has been developed for the treatment of drug-resistant bacterial wound infections and has exhibited enhanced therapeutic efficacy through the synergistic effects of photothermal therapy, chemodynamic therapy, Cu2+ions, and H2S. The DMCC exhibited exceptional biocompatibility and could release CuS, Cu2+, and H2S in response to elevated concentrations of glutathione within the biofilm microenvironment. H2S effectively disrupted the biofilm structure. Meanwhile, peroxidase activity of CuS combined with GSH-mediated reduction of Cu2+ to Cu+ generated abundant hydroxyl radicals under acidic conditions, leading to efficient eradication of pathogenic bacteria. Furthermore, both H2S and Cu2+ could modulate M2 macrophages polarization and regulate immune microenvironment dynamics. These strategies collectively provided a novel approach for developing antibacterial nanomedical platforms.

Rational Design and Engineering of Terminal Functional Groups in Dibenzothiophene‐Diphenylamine Small Molecular Electron Donors for Enhanced Photovoltaic Efficiency in All‐Small‐Molecule Organic Solar Cells

AbstractAll‐small‐molecule organic solar cells (ASM‐OSCs) offer advantages like well‐defined molecular structures and excellent reproducibility. However, lower photovoltaic efficiencies hinder their adoption due to limitations in designing small molecular electron donors (SMEDs) with optimal energy levels, light absorption, and optoelectronic properties. The present study addresses this gap by rationally designing a series of SMEDs (DBT‐2FA1 to DBT‐2FA6) through terminal acceptors engineering into dibenzothiophene core with diphenylamine side donors for potential applications in ASM‐OSCs. Density functional theory simulations are carried‐out to establish structure‐property relationships based on structural, electrochemical, photophysical, and charge transfer (CT) properties. Results show that the SMEDs exhibit low‐lying HOMOs for suitable energy level alignment with benchmark Y6 acceptor, promoting open‐circuit voltage and charge separation. The panchromatic absorption spectra covering Vis‐NIR region and maximum light harvesting efficiency are beneficial for high current‐density in ASM‐OSCs. Notably, the push‐pull mechanism within SMEDs results in dominant intramolecular CT with above 70% CT excitations. Whereas, a moderate variation in dipole moments and electrostatic potential differences with acceptor material led to 99.9% intermolecular CT, thus ensuring robust exciton dissociation and efficient photocurrent generation. Overall, this work provides a molecular‐level understanding of designing novel SMEDs and their compatibility with acceptor materials for developing future high‐performance ASM‐OSCs.