Cu2ZnSnS4 is a promising solar absorbing material in solar cells due to its high absorption coefficient and abundance on earth. We have demonstrated that wurtzite Cu2ZnSnS4 nanoleaves could be synthesized through a facile solution-based method. Detailed investigation of the growth process indicates that α-Cu2S nanocrystals are first formed and then serve as a catalyst to introduce the Cu, Zn, and Sn species into the nanoleaf growth for fast ionic conduction. The structure of the as-synthesized nanoleaves is characterized by powder X-ray diffraction, high-resolution transmission electron microscopy, fast Fourier transform, and energy dispersive X-ray spectroscopy mapping. Photoresponses of Cu2ZnSnS4 nanoleaves are evaluated by I–V curves of a Cu2ZnSnS4 nanoleaf film. It is believed that the enhancement of the photoresponse current of the Cu2ZnSnS4 nanoleaf film can be attributed to fast carrier transport due to the single crystalline nature and enhanced light absorption resulting from larger absorption areas of the Cu2ZnSnS4 nanoleaves.
Yi Li,Yanghan Chen,Tao Chen,Guoqiang Shi,Lin Zhu,Ye Sun,Miao Yu
Ethanol (C2H5OH) is an economically ideal C2 product in electrochemical CO2 reduction. However, the CO2-to-C2H5OH conversion yield has been rather low and the underlying catalytic mechanism remains vague or unexplored in most cases. Herein, by decorating small Cu2S nanocrystals uniform ly on Cu nanosheets, three desirable features are integrated into the electrocatalyst, including a relatively high positive local charge on Cu (Cuδ+), abundant interfaces between Cuδ+ and zero-valence Cu0, and a non-flat, stepped catalyst surface, leading to the promoted affinity of *CO, decreased *COCO formation barrier, and thermodynamically preferred *CH2CHO-to-*CH3CHO conversion. As a result, a high partial current density of ∼20.7 mA cm–2 and a Faraday efficiency of 46% for C2H5OH are delivered at −1.2 V vs reversible hydrogen electrode in an H-cell containing a 0.1 M KHCO3 solution. This work proposes an efficient strategy for the high-yield CO2-to-C2H5OH conversion, emphasizing the promise for the industrial production of alcohol and related products from CO2.
Heterovalent doping represents an effective method to control the optical and electronic properties of semiconductor nanocrystals (NCs), such as the luminescence and electronic impurities (p-, n-type doping). Considering the phase structure diversity, coordination varieties of Cu atoms in Cu 2 S NCs, and complexity of Cu doping in II-VI NCs, monodisperse Cu 2 S NCs with pure hexagonal phase were synthesized firstly. Then through cation exchange reaction between Cd ions and well-defined Cu 2 S NCs, dominant Cu(I) doped CdS NCs were produced successfully. The substitutional Cu(I) dopants with controllable concentrations were confirmed by local atom-specific fine structure from X-ray absorption near edge structure (XANES), extended X-ray absorption fine structure (EXAFS) spectroscopy, elemental analysis characterizations from X-ray photoelectron spectroscopy (XPS) and the electron spin resonance (ESR) measurement. The dominant and strong Cu(I) dopant fluorescence was verified by their absorption and photoluminescence (PL) spectra, and PL lifetime. Finally, the band positions and the p-type conductivities of the as-prepared Cu 2 S and Cu(I) doped CdS NCs were identified by ultraviolet photoelectron spectroscopy (UPS) measurements. The high monodispersity of NCs enables their strong film-scale self-assembly and will hasten their subsequent applications in devices.
危险品化学品经营许可证（带存储）