Colloidal quantum dots (QDs) of I-III-VI ternary compounds such as copper indium sulfide (CIS) and copper indium selenide (CISe) have been under intense investigation due to both their unusual photophysical properties and considerable technological utility. These materials feature a toxic-element-free composition, a tunable bandgap that covers near-infrared and visible spectral energies, and a highly efficient photoluminescence (PL) whose spectrum is located in the reabsorption-free intragap region. These properties make them attractive for light-emission and light-harvesting applications including photovoltaics and luminescent solar concentrators. Despite a large body of literature on device-related studies of CISe(S) QDs, the understanding of their fundamental photophysical properties is surprisingly poor. Two particular subjects that are still heavily debated in the literature include the mechanism(s) for strong intragap emission and the reason(s) for a poorly defined (featureless) absorption edge, which often "tails" below the nominal bandgap. Here, we address these questions by conducting comprehensive spectroscopic studies of CIS QD samples with varied Cu-to-In ratios using resonant PL and PL excitation, femtosecond transient absorption, and magnetic circular dichroism measurements. These studies reveal a strong effect of stoichiometry on the concentration of Cu Cu defects (occurring as Cu and Cu species, respectively), and their effects on QD optical properties. In particular, we demonstrate that the increase in the relative amount of Cu Cu centers suppresses intragap absorption associated with Cu states and sharpens band-edge absorption. In addition, we show that both Cu and Cu centers are emissive but are characterized by distinct activation mechanisms and slightly different emission energies due to different crystal lattice environments. An important overall conclusion of this study is that the relative importance of the Cu Cu emission/absorption channels can be controlled by tuning the Cu-to-In ratio, suggesting that the control of sample stoichiometry represents a powerful tool for achieving functionalities (., strong intragap emission) that are not accessible with ideal, defect-free materials.
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http://dx.doi.org/10.1021/acsnano.9b09181 | DOI Listing |
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January 2025
Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024, China.
The properties and device applications of 2D semiconductors are highly sensitive to intrinsic structural defects due to their ultrathin nature. CuInSe (CIS) materials own excellent optoelectronic properties and ordered copper vacancies, making them widely applicable in photovoltaic and photodetection fields. However, the synthesis of 2D CIS nanoflakes remains challenging due to the nonlayered structure, multielement composition, and the competitive growth of various by-products, which further hinders the exploration of vacancy-related optoelectronic devices.
View Article and Find Full Text PDFSci Rep
January 2025
Imec, imo-imomec, Thor Park 8320, 3600, Genk, Belgium.
This study presents a comprehensive evaluation of Copper Indium Gallium Selenide (CIGS) solar technology, benchmarked against crystalline silicon (c-Si) PERC PV technology. Utilizing a newly developed energy yield model, we analyzed the performance of CIGS in various environmental scenarios, emphasizing its behavior in low-light conditions and under different temperature regimes. The model demonstrated high accuracy with improved error metrics of normalized mean bias error (nMBE) ~ 1% and normalized root mean square error (nRMSE) of ~ 8%-20% in simulating rack mounted setup and integrated PV systems.
View Article and Find Full Text PDFNanomaterials (Basel)
December 2024
Division of Physics, Engineering, Mathematics and Computer Sciences and Optical Science Center for Applied Research, Delaware State University, Dover, DE 19901, USA.
This study offers a comprehensive summary of the current states as well as potential future directions of transparent conducting oxides (TCOs), particularly tin-doped indium oxide (ITO), the most readily accessible TCO on the market. Solar cells, flat panel displays (FPDs), liquid crystal displays (LCDs), antireflection (AR) coatings for airbus windows, photovoltaic and optoelectronic devices, transparent p-n junction diodes, etc. are a few of the best uses for this material.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
TU Berlin University: Technische Universitat Berlin, Fachbereich Keramische Werkstoffe, Hardenbergstr. 40, 10623, Berlin, GERMANY.
Carbon dioxide hydrogenation to methanol is a key chemical reaction to store energy in chemical bonds, using carbon dioxide as an energy sink. Indium oxide is amongst the most promising candidates for replacing the copper and zinc oxide catalyst, which is industrially applied for syngas mixtures but less idoneous for educts with carbon dioxide due to instability reasons. The polymorph of indium oxide and the operating conditions remain to be optimized for optimal and stable performance.
View Article and Find Full Text PDFInductively coupled plasma mass spectrometry was employed to determine the content of 25 inorganic elements in Bambusae Concretio Silicea, and the elemental fingerprint was established according to the element content. SPSS 20.0 and SIMCA 14.
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