Narayan Chandra Deb Nath

Fermi energy level tuning for high performance dye sensitized solar cells using sp2 selective nitrogen-doped carbon nanotube channels

Here, we find that doping sp(2) selective nitrogen, N sp(2), into carbon nanotube (CNT) channels induces a positive shift in the Fermi level of TiO(2) photoelectrodes. It is found that this results in the large diffusion coefficient of solar driven electrons for increasing the photocurrent as well as in the low recombination rate for improving open circuit voltage with 0.74 V, which could not be overcome by using pristine CNT channels with 0.66 V.

Deprotonation of N3 adsorbed on TiO2 for high-performance dye-sensitized solar cells (DSSCs)

Chemical modification of a N3-adsorbed TiO2 photoelectrode with 1-methyl-3-phenylpropylamine enhanced the power conversion efficiency (η) by ca. 15% compared to DSSCs containing pristine N3 by increasing the short circuit current density (Jsc) and open circuit voltage (Voc).

Interference-Free Determination of Dopamine at the Poly(thionine)-Modified Glassy Carbon Electrode

A highly selective and sensitive electrochemical method, based on a poly(thionine)-modified glassy carbon electrode (PTH-GCE), was developed for the determination of dopamine (DA). The modified electrode was characterized by electrochemical techniques and an atomic force microscope (AFM). The modified GCE exhibited catalytic behavior towards the oxidation of DA in 0.1 M pH 7.0 phosphate buffer solution (PBS). In differential pulse voltammetry (DPV) measurements, the oxidation peak potential of ascorbic acid (AA), uric acid (UA) and serotonin (5-HT) overlapped with that of DA at the bare GCE. However, the oxidation peak of 5-HT was separated from that of DA at the PTH-GCE while the oxidation of AA and UA were suppressed at the same time. The peak potential separation of ca. 0.2 V was large enough for selective determination of DA from the interference of 5-HT. A linear range of 5.0―35.0 μM and a detection limit (S/N = 3) of 0.2 μM were obtained for DA detection in PBS (pH 7.0). This approach provides a simple and easy method to detect DA selectively from the interferences of AA, UA and 5-HT.

A Facile Synthesis of Granular ZnO Nanostructures for Dye-Sensitized Solar Cells

Granular ZnO nanostructures of single-crystalline wurtzite hexagonal phases were synthesized by a facile and low-cost chemical method in aqueous condition. The average size of ZnO nanograin increased with reflux time, and it significantly affected the open circuit potential while the short circuit current density was not changed much. The overall energy conversion efficiency was 1.82% with the smaller grain size of ca. 250 nm when it was used as photoelectrode of DSSCs. The positive shifting of the Fermi energy () and low density of surface states (DOS) were consistent with the reduction of the recombination of excited electron with electrolyte for smaller grains.

Physical and Electrochemical Properties of Polyaniline-Ionic Liquid Composite

전도성 고분자로 널리 알려진 폴리아닐린과 액체전해질의 핵심 재료인 이온성 액체와의 복합체를형성시키고 이들의 물리적, 전기화학적인 특성을 조사되었다. 이미다졸늄 이온성 액체 (1-methyl-3-propylimidazolium iodide, PMI-I)에 비전도성 폴리아닐린 (Emeraldine Base)을 30 wt%이상첨가하였을 때 준고형화 현상이 나타났고, 이온성 액체의 이미다졸늄 양이온의 방향족 고리와 폴리아닐린의 벤족기와의 π−π 자기상호조립에 의한 약한 도핑작용을 통해 섬유상 구조를 나타내었으며, 전도도의 변화율은 80%이상 유지하였다.Abstract : Polyaniline-ionic liquid composite was prepared and investigated its physical andelectrochemical properties. The quasi-solidification was presented in imidazolium-based ionic liquid(1-methly-3-propylimidazolium iodide, PMI-I) containing above 30 wt% of polyaniline (emer-aldine base), which exhibited around 80% decrease of conductivity compared to pristine ionicliquid, resulting in fibril structure trough π−π self-assembled of imidazolium aromatic ring ofionic liquid on polyaniline framework.Keywords: Ionic Liquid, Polymer Composite, Quasi-Solidification, Quasi Solid-State Electrolyte