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Niobium doped TiO2 nanorod arrays as efficient electron transport materials in photovoltaic
摘要： One-dimensional (1-D) rutile TiO2 nanorod arrays (NRAs) synthesized by a hydrothermal method suffer from low electrical conductivity and large amounts of surface defects, hindering their further applications. Nb doping is thus introduced to modify their electronic properties. Results indicate that light Nb doping reduces rod nanosizes, increases electron concentrations, decreases surface defective oxides and lowers conduction band of the TiO2 NRAs, while heavy doping induces transformations of morphologies and crystalline orientations as well as occurrences of compositional deviations and low oxidative states of Ti3t. After 0.1 mol% and 1 mol% Nb incorporations, device efficiencies are substantially improved by ~16% and ~33% for the model perovskite and dye-sensitized solar cells, respectively, which are ascribed to reduced recombination at the perovskite/TiO2 interfaces (e.g. charge lifetime increasing from 62 μs to 107 μs) and improved electron transport through the photoanode of TiO2 NRAs (e.g. electron diffusion length increasing from ~14 μm to ~50 μm). Our study verifies that Nb doped 1-D TiO2 NRAs are versatile electron transporting materials in different kinds of emerging solar cells, and are also potential for other fields including photocatalysis, sensors and batteries etc.
关键词： TiO2 nanorod array,Dye-sensitized solar cell,Niobium doping,Charge transport,Perovskite solar cell,Recombination
更新于2025-09-19 17:13:59
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Hole Conduction of Tungsten Diselenide Crystalline Transistors by Niobium Dopant
摘要： In spite of its ambipolar character, tungsten diselenide (WSe2) is known as one of a few p-type materials among transition metal dichalcogenides and is currently being used as a fundamental building block of homo- and hetero-junctions to meet the essential requirement of electronic devices. Many studies have solved the hole transport of WSe2 by contact engineering; however, another route is shown by an effective p-doping strategy for achieving reliable p-type transistor. Diverse characterization methods confirm the transition of the Fermi level from near midgap in intrinsic WSe2 to lower half bandgap with niobium substitutional doping, leading to a nondegenerate doping level exceeding a 1017–1018 cm?3 hole concentration. As a consequence, current on/off ratio and swing parameter have improved correspondingly as expected. The WSe2 transistors (with and without doping) are examined by the Zerbst-type method to conduct the transient data analysis enabling the systemic characterization of the generation lifetime and surface generation velocity of WSe2. It is demonstrated that the lifetime for WSe2 is commonly in the 0.5–0.1 μs range. The generation velocity is ≈10 000-fold slower than that of the typical crystalline silicon, which is attributed to the ultrathin body nature of the materials.
关键词： p-type,niobium doping,tungsten diselenide,transistors,lifetime
更新于2025-09-10 09:29:36