Jathar Sagar B, Rondiya Sachin R, Jadhav Yogesh A, Nilegave Dhanaraj S, Cross Russell W, Barma Sunil V, Nasane Mamta P, Gaware Shankar A, Bade Bharat R, Jadkar Sandesh R, Funde Adinath M, Dzade Nelson Y
School of Energy Studies, Savitribai Phule Pune University, Pune 411007, India.
School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, Wales, United Kingdom.
Chem Mater. 2021 Mar 23;33(6):1983-1993. doi: 10.1021/acs.chemmater.0c03223. Epub 2021 Mar 3.
Ternary CuSnS (CTS) is an attractive nontoxic and earth-abundant absorber material with suitable optoelectronic properties for cost-effective photoelectrochemical applications. Herein, we report the synthesis of high-quality CTS nanoparticles (NPs) using a low-cost facile hot injection route, which is a very simple and nontoxic synthesis method. The structural, morphological, optoelectronic, and photoelectrochemical (PEC) properties and heterojunction band alignment of the as-synthesized CTS NPs have been systematically characterized using various state-of-the-art experimental techniques and atomistic first-principles density functional theory (DFT) calculations. The phase-pure CTS NPs confirmed by X-ray diffraction (XRD) and Raman spectroscopy analyses have an optical band gap of 1.1 eV and exhibit a random distribution of uniform spherical particles with size of approximately 15-25 nm as determined from high-resolution transmission electron microscopy (HR-TEM) images. The CTS photocathode exhibits excellent photoelectrochemical properties with PCE of 0.55% (fill factor (FF) = 0.26 and open circuit voltage (Voc) = 0.54 V) and photocurrent density of -3.95 mA/cm under AM 1.5 illumination (100 mW/cm). Additionally, the PEC activities of CdS and ZnS NPs are investigated as possible photoanodes to create a heterojunction with CTS to enhance the PEC activity. CdS is demonstrated to exhibit a higher current density than ZnS, indicating that it is a better photoanode material to form a heterojunction with CTS. Consistently, we predict a staggered type-II band alignment at the CTS/CdS interface with a small conduction band offset (CBO) of 0.08 eV compared to a straddling type-I band alignment at the CTS/ZnS interface with a CBO of 0.29 eV. The observed small CBO at the type-II band aligned CTS/CdS interface points to efficient charge carrier separation and transport across the interface, which are necessary to achieve enhanced PEC activity. The facile CTS synthesis, PEC measurements, and heterojunction band alignment results provide a promising approach for fabricating next-generation Cu-based light-absorbing materials for efficient photoelectrochemical applications.
三元铜锡硫（CTS）是一种具有吸引力的无毒且储量丰富的吸收材料，具有适合用于经济高效的光电化学应用的光电特性。在此，我们报告了使用低成本简便热注入路线合成高质量CTS纳米颗粒（NPs），这是一种非常简单且无毒的合成方法。使用各种先进的实验技术和原子级第一性原理密度泛函理论（DFT）计算，对合成的CTS NPs的结构、形态、光电和光电化学（PEC）特性以及异质结能带排列进行了系统表征。通过X射线衍射（XRD）和拉曼光谱分析确认的纯相CTS NPs具有1.1 eV的光学带隙，并且从高分辨率透射电子显微镜（HR-TEM）图像确定，呈现出尺寸约为15 - 25 nm的均匀球形颗粒的随机分布。CTS光阴极表现出优异的光电化学特性，在AM 1.5光照（100 mW/cm²）下，光电转换效率（PCE）为0.55%（填充因子（FF） = 0.26，开路电压（Voc） = 0.54 V），光电流密度为 -3.95 mA/cm²。此外，研究了CdS和ZnS NPs作为可能的光阳极与CTS形成异质结以增强PEC活性的PEC活性。结果表明，CdS比ZnS表现出更高的电流密度，这表明它是与CTS形成异质结的更好的光阳极材料。一致地，我们预测CTS/CdS界面处为交错型II能带排列，导带偏移（CBO）为0.08 eV，而CTS/ZnS界面处为跨越型I能带排列，CBO为0.29 eV。在II型能带排列的CTS/CdS界面处观察到的小CBO表明电荷载流子在界面处有效分离和传输，这是实现增强的PEC活性所必需的。简便的CTS合成、PEC测量和异质结能带排列结果为制造用于高效光电化学应用的下一代铜基光吸收材料提供了一种有前景的方法。
