This present work deals with CdSe/CdTe core-shell-based structures of type II QDs that critically rely on their synthesis processes and are examined with traditional powder X-ray diffraction (PXRD), SEM-EDX, TEM, and SAED pattern and optical characterization (UV-Vis, PL spectrum). Because of the exciton dispersion of heterostructure spatial separation, nanostructures can allow access to longer wavelengths than shell materials or single-core atoms. At the moment, core-shell nanostructures of CdTe are being developed, in which conduction of core and valence bands are generally larger (or smaller) in comparison to that of the shell. As a result, it is critical to synthesize materials with exceptional stability, a limited size range, and significant luminous performance. In general, the efficiency of unique photovoltaic device conversion is constrained by the solar energy distribution system which is associated with the host materials’ bandgap.
#Core shell free#
Another factor affecting performance is photoinduced excitons dissociating into holes and free electrons, rather than recombination. However, a critical factor limiting conversion capability is going to be the rapid relaxing of high-energy excitons (photostimulated) into low-energy excitons, resulting in excess energy from their conversion to heat energy via photon emission. In recent years, CdSe-CdTe heterostructures have been developed to improve the integration of CdTe and selenide components in solar cell structures for the compelling benefits of a number of these desirable features.
Following solar energy conversion and in conjunction with the use of heterostructures, nanostructures give various compensations, one of which is the quick exciton dissociation. Due to the tunable architecture, nanomaterials especially the core-shell nanostructures have an impact in most of the thrust research areas in recent years. With the rapid advancement of synthesis, characterization, and methods, scientists have discovered that combining multicomponent nanomaterials and tuning their composition profile can result in more desirable properties such as textural morphology and electrical and optical behaviour which leads to enhancement of their applications in a wide variety of fields. Nanoscience and nanotechnology breakthroughs have unlocked several possibilities in various fields, including solar cell systems, photodetectors, electrical injection lasers, and optical waveguides. The UV-Vis absorption bands at 455 nm and 560 nm confirm exciton emission due to the type II matrix of CdSe/CdTe QDs. The demonstrated monodispersed lattice structure of core-shell CdSe/CdTe QDs has excellent PL emission properties at which is suitable for photovoltaic applications. The correlation between the synthesis procedures and the corresponding structures of the core-shell CdSe/CdTe QDs is discussed. Significant results of the SAED pattern confirm the core and shell components as CdSe and CdTe, respectively. TEM results suggest that the size of spherical CdSe/CdTe core-shell QDs is in the range of 8~10 nm. EDX confirms the elemental presence of Cd, Se, and Te in the compound. SEM morphology confirms the uniformly distributed nanoscale CdSe/CdTe with no agglomeration. The XRD results reveal the formation of mixed phases of CdSe and CdTe with a grain size of 12.6 nm. A simple hydrothermal method is developed for the synthesis of high-quality type II core-shell CdSe/CdTe quantum dots (QDs).
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