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Novel cobalt redox materials admitted in natrosol polymer with a thiophene based additive as a gel polymer electrolyte to tune up the efficiency of dye sensitized solar cells
摘要： Synthesis of novel cobalt redox pairs such as Co2+/3+[bnbip]2, Co2+/3+[npbi]3, Co2+/3+[b(ttb)bip]2 and unknown organic additive integrated into a new natrosol polymer host act as an polymer gel electrolytes in DSSC. The newly synthesized ligands and organic additive (BNBIT) was characterized by 1H, 13C NMR and HRMS spectroscopy and complexes were confirmed by UV-Visible, FTIR and ESI-MS spectrum. Electrochemical analysis was determined for all new redox pairs in that Co2+/3+[bnbip]2 shows positive E1/2value 0.51 V Vs NHE and higher formal potential 0.55 V which leads a way to increase in open circuit voltage of DSSC. The new natrosol polymer gel electrolytes was characterized by using UV-Visible, FTIR, DSC, XRD, impedance spectrum and I-V curve. The conductivity increases up to 7.14x10-4Scm-1 for natrosol polymer gel electrolyte with a novel organic additive and stable Co2+/3+[bnbip]2 redox pair. The new organic additive plays a vital role in DSSC device which shields the Co3+ ions of the redox pair in gel electrolytes and interaction with TiO2 surface that made shift in quasi Fermi level of TiO2 which suppresses the recombination processes. The new natrosol polymer gel electrolytes with novel cobalt redox pairs and thiophene based organic additive that enhances the efficiency up to 4.5% under light illumination of 100mW/cm2 with a better stability. A increase in photocurrent due to BNBIT organic additive and the best E1/2 value of Co2+/3+[bnbip]2 mediator which made shift in (EF,n) quasi Fermi level of TiO2 that mitigate the recombination process in DSSCs. The interfacial studies in DSSCs were focused via EIS to elucidate the charge transport mechanisms at the interfaces of photoelectrodes and electrolyte medium of the devices.
关键词： quasi Fermi level.,organic additive,Dye sensitized solar cells,HEC polymer gel electrolyte,novel cobalt redox pairs
更新于2025-09-11 14:15:04
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Transparent p-Cu0.66Cr1.33O2/n-ZnO heterojunction prepared in a five-step scalable process
摘要： Transparent and electrical conducting p-type off-stoichiometric copper–chromium oxide thin films were used to build p-Cu0.66Cr1.33O2/n-ZnO heterojunctions. The junctions were fabricated in a novel and simple five step process including metal organic chemical vapour deposition, atomic layer deposition, chemical wet etching, and optical lithography. One last step of thermal annealing, with varying temperatures of 650 and 700 °C, is added in order to tune the electrical properties of delafossite and consequently the electrical features of p–n junctions. This work was developed to address the lack of transparent and industrially scalable rectifying p–n junctions that can open multiple application paths in transparent electronics. A competitive ideality factor η of 6.6 and a transmittance in the visible range of 50% were achieved. An understanding of the electronic response of junctions is presented herein as well as a deepening comprehension of the physical properties of materials, with the bands alignment and the Fermi level tuning.
关键词： Atomic layer deposition,Optical lithography,Thermal annealing,Delafossite,Metal organic chemical vapour deposition,p-Cu0.66Cr1.33O2/n-ZnO heterojunctions,Transparent electronics,Chemical wet etching,Fermi level tuning
更新于2025-09-10 09:29:36
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Evidence for Primal sp <sup>2</sup> Defects at the Diamond Surface: Candidates for Electron Trapping and Noise Sources
摘要： Many advanced applications of diamond materials are now being limited by unknown surface defects, including in the fields of high power/frequency electronics and quantum computing and quantum sensing. Of acute interest to diamond researchers worldwide is the loss of quantum coherence in near-surface nitrogen-vacancy (NV) centers and the generation of associated magnetic noise at the diamond surface. Here for the first time is presented the observation of a family of primal diamond surface defects, which is suggested as the leading cause of band-bending and Fermi-pinning phenomena in diamond devices. A combination of density functional theory and synchrotron-based X-ray absorption spectroscopy is used to show that these defects introduce low-lying electronic trap states. The effect of these states is modeled on band-bending into the diamond bulk and it is shown that the properties of the important NV defect centers are affected by these defects. Due to the paramount importance of near-surface NV center properties in a growing number of fields, the density of these defects is further quantified at the surface of a variety of differently-treated device surfaces, consistent with best-practice processing techniques in the literature. The identification and characterization of these defects has wide-ranging implications for diamond devices across many fields.
关键词： surfaces,Fermi-level pinning,defects,diamond,NEXAFS
更新于2025-09-10 09:29:36
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Dramatically enhanced photoelectrochemical properties and transformed p/n type of g-C3N4 caused by K and I co-doping
摘要： Graphitic carbon nitride (g-C3N4) usually shows amphoteric property in a neutral solution. In this work, a K&I co-doped g-C3N4 is prepared by simply sintering the mixture of dicyandiamine, KI and I2. The K&I co-doping modulates the band structure of g-C3N4 with pulling the Fermi level toward its conduction band minimum. The obtained K&I co-doped g-C3N4 (K&I-C3N4) generates positive photocurrents over the whole investigated potential range, exhibiting a typical n-type semiconductor characteristic. Therefore, the K&I co-doping transforms the g-C3N4 from amphoteric to n-type semiconductor. Also, the prepared K&I-C3N4 shows widened light absorption range and enhanced separation efficiency of the photogenerated charge carriers, which results in the dramatically enhanced photoelectrochemical performance.
关键词： Photoelectrochemical performance,K&I co-doping,Fermi level,p/n type,Graphitic carbon nitride
更新于2025-09-10 09:29:36
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First Experimental Demonstration and Mechanism of Abnormal Palladium Diffusion Induced by Excess Interstitial Ge
摘要： This letter represents the ?rst direct experimental demonstrations and mechanism proposal regarding abnormal palladium diffusion into germanium (Ge). Our experiments indicated that excess Ge atoms among palladium germanide alloy formation indirectly induce the abnormal out-diffusion of mass palladium atoms into Ge. Consequently, palladium germanide alloy on both n-type and p-type Ge form ohmic-like Schottky junctions. To identify this phenomenon, ?rst-principle calculations and technology computer-aided design simulation were used to evaluate the electrical in?uence of palladium atoms in Ge. We discovered that the activated palladium atoms in Ge induce large midgap bulk-trap states, which contribute to a severe increment of trap-assisted tunneling current at the palladium germanide/Ge junction.
关键词： Schottky junction,First-principles calculations,palladium germanide,technology computer-aided design,germanium,trap-assisted tunneling,fermi-level pinning effect
更新于2025-09-10 09:29:36
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Band Gap Width Control by Cu Intercalation into ZrSe <sub/>2</sub>
摘要： The CuxZrSe2 intercalation single crystals have been synthesized and studied in a concentration range of x = 0 – 0.3, in which the semiconductor-metal transition was observed. The evolution of the electronic structure of CuxZrSe2 as a function of the copper content has been studied experimentally using the XPS and XAS methods. The obtained results indicate the gradual shift of the Fermi level with increasing copper content, which does not allow the metal-insulator transition to be associated with charge transfer to the conduction band. This transition is associated with the formation of the covalent bond between copper and the nearest selenium atoms and of the p-d hybridized states inside the Zr 4d/Se 4p band gap. First-principle calculations were performed in order to obtain a theoretical description of the density of states near the Fermi level and confirm this conclusion.
关键词： first-principle calculations,covalent bond,Fermi level,CuxZrSe2,semiconductor-metal transition,XPS,XAS,p-d hybridized states,intercalation,electronic structure
更新于2025-09-04 15:30:14
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<i>In-Situ</i> Measurement and Control of the Fermi Level in Colloidal Nanocrystal Thin Films during Their Fabrication
摘要： In engineering a high-performance semiconductor device, understanding of the Fermi level position is critical. Here, we demonstrate that open-circuit potential (OCP) measurements can be used to quantify the Fermi level in nanocrystal thin films in-situ during their solution-based fabrication. We use this method to study the influence of (1) a metal contact and (2) nanocrystal surface termination on the Fermi level of the nanocrystal film, and find that oxidization or reduction of the nanocrystals as well as surface terminations with dipoles can be used to tune the Fermi level over large energy ranges. Finally, to emphasize the compatibility of the technique with device fabrication, we show that we can use blends of ligands to design the Fermi level landscape in a nanocrystal film. Our work highlights that OCP measurements can be used to gain insights into existing device operation and direct further optimization of optoelectronic devices.
关键词： Fermi level,nanocrystals,quantum dots,electronic structure,In-situ measurement
更新于2025-09-04 15:30:14