Abstract
Quasi-type II heterostructured nanocrystals (NCs) have been of particular interest due to their great potential for controlling the interplay of charge carriers. However, the lack of material choices for quasi-type II NCs restricts the accessible emission wavelength from red to near-infrared (NIR), which hinders their use in light-emitting applications that demand a wide range of visible colors. Herein, we demonstrate a new class of quasi-type II nanoemitters formulated in ZnSe/ZnSe 1- X Te X /ZnSe seed/spherical quantum well/shell heterostructures (SQWs) whose emission wavelength ranges from blue to orange. In a given geometry, ZnSe 1- X Te X emissive layers grown between the ZnSe seed and the shell layer are strained to fit into the surrounding media, and thus, the lattice mismatch between ZnSe 1- X Te X and ZnSe is effectively alleviated. In addition, composition of the ZnSe 1- X Te X emissive layer and the dimension of the ZnSe shell layer are engineered to tailor the distribution and energy of electron and hole wave functions. Benefitting from the capabilities to tune the charge carriers on demand and to form defect-free heterojunctions, ZnSe/ZnSe 1- X Te X /ZnSe/ZnS NCs show near-unity photoluminescence quantum yield ( PL QY > 90 % ) in a broad range of emission wavelengths (peak PL from 450 nm to 600 nm). Finally, we exemplify dichromatic white NC-based light-emitting diodes (NC-LEDs) employing the mixed layer of blue- and yellow-emitting ZnSe/ZnSe 1- X Te X /ZnSe/ZnS SQW NCs.
Highlights
Colloidal semiconductor nanocrystals (NCs), in which charge carriers are confined in all three dimensions, have received tremendous interest as next-generation lightemissive materials owing to their unique optical properties such as broad absorption but narrow emission bandwidth and size-dependent band gap tunability across visible to near IR [1,2,3,4]
As a new class of quasi-type II NCs, we construct heterojunctions made of ZnSe1-XTeX emissive layer passivated by a ZnSe shell layer for the following reasons
The energy offset between conduction band edge energy levels (ECBE) of ZnSe and ZnSe1-XTeX is similar to the thermal energy of room temperature, allowing the electron wave function to spread over the entire volume of NCs
Summary
Colloidal semiconductor nanocrystals (NCs), in which charge carriers are confined in all three dimensions, have received tremendous interest as next-generation lightemissive materials owing to their unique optical properties such as broad absorption but narrow emission bandwidth and size-dependent band gap tunability across visible to near IR [1,2,3,4]. The representative is the core/shell heterostructures, wherein the charge carriers in the core are decoupled from the surface trap states to award photochemical stability and near-unity luminescence efficiency at room temperature [11,12,13]. Among the core/shell heterostructures, NCs with the quasi-type II band alignment have been of particular interest due to their great potential for controlling the interactions among charge carriers. The distinguished feature of quasi-type II heterostructured NCs is the suppression of nonradiative Auger recombination processes of multicarriers
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
