Electronic Structure of 1D Lepidocrocite TiO 2 as Revealed by Optical Absorption and Photoelectron Spectroscopy
Electronic Structure of 1D Lepidocrocite TiO 2 as Revealed by Optical Absorption and Photoelectron Spectroscopy
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光学吸收和光电子能谱揭示一维纤铁矿TiO 2 的电子结构
DOI：
10.1021/acs.jpcc.2c06719
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Titova, Lyubov V.
中科院分区：
文献类型：
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作者：
Colin-Ulloa, Erika;Martin, Julia L.;Hanna, Ryan J.;Frasch, Michelle H.;Ramthun, Rebecca R.;Badr, Hussein O.;Uzarski, Joshua R.;Barsoum, Michel W.;Grimm, Ronald L.;Titova, Lyubov V.
我们最近展示了一维二氧化钛纤铁矿微丝的可扩展的一锅法合成，其通过使含Ti的水不溶性的、地球上丰富的化合物如TiC、TiB 2、TiN等反应，与四烷基氢氧化铵TMAOH在85 °C下在环境压力下反应几天。所得的一维纤铁矿（1DL）二氧化钛基纳米丝（NF）倾向于沿[100]生长方向沿着自排列以形成有时自排列成伪二维（2D）片的微丝。在亚平方纳米横截面的情况下，所得到的带隙能量Eg在4.0eV处是二氧化钛材料有史以来报道的最高之一。尽管一个大的带隙，纳米丝表现出显着的吸光度在整个可见光谱归因于间隙内的缺陷状态的基础上的UV-Vis吸光度数据和紫外光电子能谱（UPS）。UP谱表明相对于真空的功函数为4.0 ± 0.3 eV，相对于价带边缘的费米能量为3.8 ± 0.1 eV。瞬态吸收（TA）光谱的1DL纳米丝薄膜与子带隙，可见光照明揭示光激发寿命超过纳秒。与已建立的氧化稳定性相结合，长寿命的可见光激发带来了1DL纳米丝在电子学和光电子学中的可能应用。
We recently demonstrated scalable, one-pot syntheses of one-dimensional, titania lepidocrocite microfilaments by reacting Ti-containing water-insoluble, earth-abundant compounds such as TiC, TiB2, TiN, etc., with tetraalkylammonium hydroxide, TMAOH, for a few days at 85 °C under ambient pressure. The resulting one-dimensional lepidocrocite (1DL) titania-based nanofilaments, NFs, tend to self-align along the [100] growth direction to form microfilaments that sometimes self-align into pseudo-two-dimensional (2D) sheets. With sub-square-nanometer cross sections, the resulting band gap energy,Eg, at 4.0 eV is one of the highest ever reported for a titania material. Despite a large band gap, the nanofilaments exhibit significant absorbance throughout the visible spectrum ascribable to intra-gap defect states based on UV–Vis absorbance data and ultraviolet photoelectron spectroscopy (UPS). UP spectra demonstrate work functions of 4.0 ± 0.3 eV vs vacuum and Fermi energies of 3.8 ± 0.1 eV with respect to the valence band edge. Transient absorption (TA) spectroscopy of the 1DL nanofilament thin films with sub-band-gap, visible-light illumination reveals photoexcitations with lifetimes in excess of nanoseconds. In combination with the established oxidative stability, long-lived visible photoexcitations bring forward possible applications of 1DL nanofilaments in photocatalysis and optoelectronics.