Narrow-Bandwidth Blue-Emitting Ag–Ga–Zn–S Semiconductor Nanocrystals for Quantum-Dot Light-Emitting Diodes

Abstract

I–III–VI type semiconductor nanocrystals (NCs) have attracted considerable attention in the display field. Herein, we realized the synthesis of narrow-bandwidth blue-emitting Ag–Ga–Zn–S (AGZS) NCs via a facile one-pot method. Intriguingly, the Ag/Zn feeding ratio and Ag/Ga feeding ratio are crucial for the realization of narrow-bandwidth AGZS NCs. By choosing a Ag/Zn feeding ratio of 4:1 and Ag/Ga feeding ratio of 1:8, AGZS NCs demonstrate a typical blue emission at 470 nm with a narrow full width at half-maximum (fwhm) of 48 nm, which is mainly generated from the band-to-hole recombination rather than the donor–acceptor pair (DAP) recombination. Furthermore, a solution-processed quantum-dot light-emitting device based on AGZS NCs exhibits a narrow electroluminescent bandwidth of 53 nm and high luminance over 123.1 cd m–2, as well as a high external quantum efficiency (EQE) of 0.40%. Our work highlights AGZS NCs with high color purity as an important candidate for blue-light-emitting devices.

I–III–VI Quantum Dots and Derivatives: Design, Synthesis, and Properties for Light-Emitting Diodes

“…Tang et al reported the narrowest blue QLEDs (48 nm) based on Ag−Ga−Zn−S QDs (Figure 4d), the ratios of cations (Ag + /Zn 2+ and Ag + /Ga 3+ ) are the crucial for narrow emission. 26 This research provides a feasible strategy for pure-monochrome emission. Tsuzuki et al reported a GaS x -passivated AIGS QD, whose defect sites are compensated, and the defect-related direct electron injection are suppressed.…”

“…Copyright 2017 Royal Society of Chemistry. (d)–(f) EL spectra of blue, green, and red QDs, and the photographs demonstrate the LEDs under voltages. ,, Adapted with permission from ref (copyright 2022 American Chemical Society), ref (copyright 2018 The Optical Society of American, under CC BY 4.0), and ref (copyright 2023 American Chemical Society).…”

“…The Zn 2+ has been reported to have strong ability in regulating emissive spectra; Tang et al discovered the extended blueshift in Zn 2+ -doped AIGS QDs. 26 The ZnS shell also blues shift spectra by limiting excited state energy. 34 In addition, the defects formed by nonstoichiometric show adjustment in emissive spectra of QDs as well, serve as radiative recombination centers.…”

“…6 Introducing homologous or heterogeneous ions (Al 3+ , Zn 2+ , Sn 4+ , Fe 3+ ) Made available for a limited time for personal research and study only License. can further derive the composition into quaternary/quinary QDs, 19 the main compounds are Ag−In−Ga−S (AIGS), 20−23 Ag−Cu−Ga−Se (ACGSe), 24 Zn−Cu−Ga−S (ZCGS), 25,26 and Zn−Ag−In−Ga−S (ZAIGS). 27 I−III−VI QDs and derivatives demonstrate flexible chemical composition and nonstoichiometric characteristics, meanwhile the defects can participate in the radiative recombination process.…”

Building in biologically appropriate multifunctionality in aqueous copper indium selenide-based quantum dots

“…Ternary I-III-VI semiconductor nanocrystals or quantum dots (QDs), such as copper indium selenide QDs, have become attractive alternatives to the more well-established Cd-, Pb-, or Hg-containing QDs for in vivo applications. [7][8][9][10][11][12] Apart from their good biocompatibility due to the absence of highly toxic elements, their relatively narrow bulk band gaps allow the tuning of photoluminescence from the visible region all the way up to the near-infrared (NIR) spectral region, [13][14][15][16][17][18][19] where penetration through biological tissue is favorable. [20][21][22][23][24] In contrast to binary Cd-free QDs, ternary QDs show compositiondependent optical properties while maintaining similar particle sizes, which endows the QDs with analogous pharmacokinetic behaviors in vivo.…”