Photo‐ and Electroluminescence from Zn‐Doped InN Semiconductor Nanocrystals

Abstract

There is a critical research need for efficient luminescent colloidal nanocrystals, free from cadmium and lead whose toxicity subjects them to usage restrictions, with applications from display devices to biology. Approaches to directly replace cadmium‐based materials have mainly focused on indium phosphide‐based nanocrystals, however these too are subject to concerns over toxicity. Few other alternatives have been found that can compete with the emission range and efficiency of Cd‐ and Pb‐based nanocrystals. Group III‐nitride nanocrystals, and their alloys, offer the exciting potential to tune bandgap energies from the ultraviolet to the near infrared yet a robust route toward efficient luminescent nitride nanocrystals is lacking. Here, the synthesis of photoluminescent indium zinc nitride quantum dots exhibiting tunable emission through the visible to near infrared spectra region, with quantum yields of up to 30% is reported. Capping the nanocrystals with both a GaN and ZnS shell significantly increases air stability and emission quantum yields. A proof‐of‐principle indium zinc nitride nanocrystal light emitting diode is also demonstrated. This work overcomes the significant challenges that have prevented the full exploration of nitride‐based semiconductor nanocrystal development, providing a new system for further exploration as a heavy‐metal free alternative to current state‐of‐the‐art materials.

Nanoscale LiZnN - Luminescent Half-Heusler Quantum Dots

“…Inspection of the low-energy tails of the materials synthesized at 260 and 270 °C clearly show extended emission, beyond the onset of absorption, that is characteristic of trap states that are commonly associated with nanocrystal surfaces. It was also observed that the full width half-maximum (fwhm) of the LiZnN emission profile (45 nm) was significantly narrower than for the parent Zn 3 N 2 material (60 nm) and recently reported InN:Zn (160 nm) . This blue-shift in optical profile from the near-IR to red spectral region is consistent with Li insertion in thin films of Zn 3 N 2 as described by Moriga et al Emission quantum yields were found to be as high as 15% (270 °C, 70 min).…”

“…It was also observed that the full width half-maximum (fwhm) of the LiZnN emission profile (45 nm) was significantly narrower than for the parent Zn 3 N 2 material (60 nm) and recently reported InN:Zn (160 nm). 18 This blue-shift in optical profile from the near-IR to red spectral region is consistent with Li insertion in thin films of Zn 3 N 2 as described by Moriga et al 19 Emission quantum yields were found to be as high as 15% (270 °C, 70 min).…”

Investigating the effect of Zn doping and temperature on the photoluminescence behaviour of CuLaSe2 quantum dots

“…However, due to their excellent stability and performance, the majority of the well studied QDs are high toxic material (such as Pb and Cd)‐based QDs. Alternative materials have been reported including CuInSe 2 [9], InZnN [10], InP [11], AgInS 2 [12], ZnAIS [13], and AIS/ZnS [14] but noticeably they have both unstable nature and poor optical properties due to mainly the fact that those nano‐materials either suffer from surface oxidation or poor surface atom coordination that results in surface trap states. There have been several methods to decrease the rate of defect sizes and therefore improve photophysical properties in environmentally friendly QDs [9, 15, 16], but they still lag behind their toxic counterparts.…”

Synthesis of Size-Tunable Indium Nitride Nanocrystals

“…We note that there was significant electron beam damage to the nanocrystals under the TEM, a common observation with III–V semiconductor nanocrystals (see Figure S4). − …”