Ln 10 S 14 O (Ln = La, Pr, Nd, Sm) Oxysulfides: A Series of Direct n-Type Semiconductors
Ln 10 S 14 O (Ln = La, Pr, Nd, Sm) Oxysulfides: A Series of Direct n-Type Semiconductors
复制标题
Ln 10 S 14 O (Ln = La, Pr, Nd, Sm) 硫氧化物：一系列直接 n 型半导体
DOI：
10.1021/acs.chemmater.2c01244
复制
发表时间：
2022
影响因子：
8.6
通讯作者：
Velázquez, Jesús M.
中科院分区：
文献类型：
--
作者：
Wuille Bille, Brian A.;Kundmann, Anna C.;Osterloh, Frank E.;Velázquez, Jesús M.
稀土硫氧化物具有磁性、光致发光、催化和光电性能，是一种很有应用前景的材料。本文报道了Ln_（10）S_（14）O（Ln = La，Ce，Pr，Nd，Sm）硫氧化物的固相合成和结构表征。然后，我们提出了一个深入的讨论，他们的电子和电子物理性质。通过Tauc图分析和吸收光谱拟合方法（DASF）的推导，确定了所有硫氧化物都具有直接带隙，其能量分别为2.84 eV（La），2.02 eV（Ce），2.56 eV（Pr），2.64 eV（Nd）和2.41 eV（Sm）。此外，表面光电压谱（SPS）显示，当在光学带隙附近照射时，含La，Pr，Nd和Sm的化合物的光电压（ΔCPD）值为−0.4至−1.1 V，表明这些氧硫化物是n型半导体，这与Mott-Schottky分析一致。子带隙照明能量下的光电压和光电压衰减数据表明，中带隙态可能源于镧系元素4f轨道和/或晶体结构内或颗粒表面的缺陷。这些物理性质表明硫氧化物在光电化学和光伏能量转换中可能的应用。
Lanthanoid oxysulfides are promising materials for technological applications owing to their magnetic, photoluminescent, catalytic, and optoelectronic properties. Herein, we report the solid-state synthesis and structural characterization of Ln10S14O (Ln = La, Ce, Pr, Nd, Sm) oxysulfides. Then, we present a thorough discussion on their electronic and photophysical properties. Through Tauc plot analysis and the derivation of the absorption spectrum fitting method (DASF), we determine that all oxysulfides have direct band gaps with energies of 2.84 eV (La), 2.02 eV (Ce), 2.56 eV (Pr), 2.64 eV (Nd), and 2.41 eV (Sm). Furthermore, surface photovoltage spectroscopy (SPS) shows photovoltage (ΔCPD) values of −0.4 to −1.1 V for La-, Pr-, Nd-, and Sm-containing compounds when illuminated near the optical band gap, indicating that these oxysulfides are n-type semiconductors, which is consistent with Mott–Schottky analysis. Photovoltages under sub-band gap illumination energy and photovoltage decay data suggest mid-band gap states possibly arising from the lanthanoid 4f orbitals and/or defects within the crystal structure or at the particle surfaces. These photophysical properties suggest possible applications of the oxysulfides in photoelectrochemical and photovoltaic energy conversion.