From Large-Scale Synthesis to Lighting Device Applications of Ternary I–III–VI Semiconductor Nanocrystals: Inspiring Greener Material Emitters

Quantum dots with fabulous size-dependent and color-tunable emissions remained as one of the most exciting inventories in nanomaterials for the last 3 decades. Even though a large number of such dot nanocrystals were developed, CdSe still remained as unbeatable and highly trusted lighting nanocrystals. Beyond these, the ternary I–III–VI family of nanocrystals emerged as the most widely accepted greener materials with efficient emissions tunable in visible as well as NIR spectral windows. These bring the high possibility of their implementation as lighting materials acceptable to the community and also to the environment. Keeping these in mind, in this Perspective, the latest developments of ternary I–III–VI nanocrystals from their large-scale synthesis to device applications are presented. Incorporating ZnS, tuning the composition, mixing with other nanocrystals, and doping with Mn ions, light-emitting devices of single color as well as for generating white light emissions are also discussed. In addition, the future prospects of these materials in lighting applications are also proposed

Supplementary document for Polarized Emission of Cs3Cu2I5 Nanowires Embedded in Nanopores of Anodic Aluminum Oxide Template - 6864447.pdf

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Hydroxyl-Terminated CuInS₂ Based Quantum Dots: Toward Efficient and Bright Light Emitting Diodes

CuInS₂ based quantum dots are emerging as low toxic materials for new generation white lighting technology due to their broad and color-tunable emissions as well as large Stokes shifts. Here, we developed a simple and <i>in situ</i> ligand exchange strategy for the fabrication of hydroxyl-terminated CuInS₂ based quantum dots capped with 6-mercaptohexanol. During the ligand exchange, long-chain methyl-terminated oleylamine on the quantum dots’ surface can be effectively and efficiently replaced by the short-chain hydroxyl-terminated 6-mercaptohexanol, enabling their solubility in polar organic solvents such as methanol, ethanol, and dimethylformamide. Moreover, the resulting hydroxyl-terminated quantum dots exhibit well-preserved photoluminescence properties with quantum yields of ∼70%. Using these hydroxyl-terminated CuInS₂ based quantum dots as an emitting layer, we fabricated efficient and bright light emitting diodes by adopting an inverted device structure. The optimized devices show a maximum luminance of 8,735 cd/m² and an external quantum efficiency of 3.22%. Furthermore, the performance enhancement can be explained by considering the decreased energy barriers between the electron transport layer and the emitting layer. The combination of high efficiency and enhanced brightness as well as the potential all-solution processability using green solvents makes hydroxyl-terminated quantum dots capped with 6-mercaptohexanol a new generation of materials for light emitting applications

Template Synthesis of CuInS₂ Nanocrystals from In₂S₃ Nanoplates and Their Application as Counter Electrodes in Dye-Sensitized Solar Cells

We report the room temperature template synthesis of CuInS₂ nanocrystals through incorporation of Cu⁺ cations into In₂S₃ nanoplates whose chemical composition has been controlled by varying the amount of copper ions in the reaction mixture. As a result, bandgaps of the resultant CuInS₂ nanoplates can be tuned from 1.45 to 1.19 eV with [Cu]/[In] molar ratios increasing from 0.7 to 2.9, which was demonstrated by the cyclic voltammetry. We explored the use of CuInS₂ nanocrystals as potential counter electrodes in dye-sensitized solar cells, and a power conversion efficiency of 6.83% was achieved without selenization and ligand exchange. The value is comparable with the performance of a control device using Pt as a counter electrode (power conversion efficiency: 7.08%) under the same device architecture