A Simple Route for Highly Luminescent Quaternary Cu-Zn-In-S Nanocrystal Emitters

Abstract

We reported a simple synthetic method for Cu–Zn–In–S nanocrystals (NCs) using commercially available, low toxic precursors. The various sizes and composition of Cu–Zn–In–S NCs were well controlled by simply changing reaction temperature and the ratio of the precursors, respectively. Accordingly, as produced these particles exhibited tunable photoluminescence (PL) spectra with emission color tuned from visible to the NIR region and had a relatively high QY of over 70% without coating any wide band gap shell materials. Further experimental results revealed that Cu–Zn–In–S NCs showed some advantages in contrast to typical plain II–VI and III–V semiconductor NCs. Preliminary tentative application on the preparation of QD-LEDs verified the feasibility in the lighting field.

Large-scale synthesis of single-source, thermally stable, and dual-emissive Mn-doped Zn–Cu–In–S nanocrystals for bright white light-emitting diodes

“…The UV-vis and PL spectra of the samples corresponded to the same samples shown in Figure 1. All samples had a common feature: a UV-vis absorption spectrum displayed featureless excitonic peaks, which was consistent with the quaternary samples reported in our previous work [31]. The band edges of samples slightly red-shifted with increased reaction temperature, indicating increased particle size as confirmed by TEM measurement (Figure 1).…”

“…The as-prepared NCs displayed a nearly spherical shape with increased mean size from 2.6 nm (180 °C), 3.6 nm (210 °C), and 4.1 nm (240 °C), as the reaction proceeded. This trend on the variation in size of NCs had been confirmed by preparing quaternary NCs in our previous report [31]. Note that the size of particles synthesized at 150 °C was difficult to be determined due to the limited TEM measurement.…”

“…With increased reaction temperature from 150 °C to 180 °C, the emission peak narrowed gradually along with a significant blue-shift in its emission peak position. These shifts reflected the formation of alloyed NCs because of the incorporation of Zn, resulting in increased band gap of the samples [31]. With further increased reaction temperature from 180 °C to 210 °C and 240 °C, the emission peak narrowed gradually along with a slight red-shift in its emission peak position.…”

“…A number of research groups focused on composition--dependent band gap tuning in alloy NCs and great success had been achieved [97][98][99][100][101][102]. For example, the PL peak position is tunable in the visible region by changing the ratio of Cu/Zn [31,[100][101][102]. Therefore, we can tune the composition of host materials as Nano Res.…”

“…Various NCs such as ZnCdS [16][17][18][19][20][21], CdSe [22][23][24][25][26], ZnCdSe [27], CuInS [28][29][30][31][32][33][34][35], and InP [36][37][38][39][40][41] NCs have been successfully applied in the fabrication of WLEDs to enhance the color properties of the device. The general methods to achieve white light emission are either by coating a yellow phosphor, by combining green and red phosphors on a background consisting of a blue light-emitting diode (LED), or by using NC of the three primary colors (red, green, blue) using multilayer structures in LEDs [14,15,[42][43][44].…”