Ternary Cu 2 SnS 3 (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 2 under AM 1.5 illumination (100 mW/cm 2 ). 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.

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Cadmium sulfide (CdS) nanoparticles were synthesized by simple and low cost homemade hot injection method at low process temperature using different sulphur sources. The effects of sulphur concentration on the structural, morphological, and optoelectronic properties of synthesized CdS films were studied using a range of characterization techniques: X-ray diffraction (XRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM) and UV-Visible spectroscopy. The XRD studies revealed the formation of hexagonal type CdS nanoparticles. The varying morphology dependence on the sulphur source was ascertained from FESEM analysis. The longitudinal optical (LO) phonon vibrational modes of CdS were assigned in Raman spectra at 300 and 600 cm-1. The band gap of the CdS particles was estimated to be 2.30 eV from Tauc's plots. Consistent with the experimental results, our first-principles DFT calculations predict the band gap of CdS nanoparticles to increase with decreasing S concentration: Cd 52 S 52 (2.38 eV) Cd 52 S 51 (2.52 eV) and Cd 52 S 50 (2.65 eV), with both the valence and conduction band edges demonstrated to be dominated by S-p states.

Inorganic metal halide perovskites CsPbX3 (X = Cl, Br, and I) has achieved extensive attention in recent years for photovoltaics because of their unique properties like tunable band gap, high charge carrier mobility, high absorption coefficient, etc. and which makes it suitable for optoelectronic applications. In this work, we have reported a facile synthesis method of inorganic CsPbBr3 nanoparticles (NPs) at room temperature using cesium bromide (CsBr) as a Cs source, lead bromide (PbBr2) as Br source, oleic acid, and Oleylamine as capping ligands. Nucleation starts immediately after the injection of a precursor solution into the toluene. Synthesis of CsPbBr3 NPs was confirmed by X-Ray diffraction pattern, UV-Visible spectroscopy, photoluminescence (PL), scanning electron microscopy (SEM), and atomic force microscopy (AFM). X-ray diffraction pattern reveals mainly the monoclinic crystal structure of CsPbBr3 NPs. The UV-Vis absorption spectra and PL spectra show a strong absorption peak at 509 nm, emission peak at 505 nm, and the band gap of CsPbBr3 to be 2.2 eV. The synthesized CsPbBr3 exhibit regular cuboid like structure with a particle size of approximately 400-500 nm. The surface roughness morphology of CsPbBr3 NPs was studied using AFM, and it shows the roughness of the CsPbBr3 films was around 260 nm. These results provide a facile synthesis method, and CsPbBr3 NPs are a suitable candidate for the optoelectronic and photovoltaic device's application.