Crystallinity and electroluminescence efficiency of CdS nanoparticles grown on the aligned carbon nanotube array

Abstract

CdS nanoparticles have been grown on multiwalled carbon nanotubes (CNTs) using a chemical bath deposition. Transmission electron microscopy and Raman spectroscopy revealed that crystalline ordering of nanoparticles depends on the duration of synthesis. Moreover, X-ray photoelectron spectroscopy showed that the surface of CdS nanoparticles contains ammonia used as a complexing agent in the reaction. Application of voltage to the substrate with array of aligned CNTs resulted in luminescence of CdS nanoparticles. Efficiency of the electroluminescence depends on the CdS crystallinity and size. Large well-crystallized nanoparticles give bright spots on the cathode image, while the glow from smaller, poor ordered nanocrystalls is strongly scattered.Bigger and better crystallized CdS nanoparticles produce brighter electroluminescence glow. Figure 4 (online color at: www.pss-b.com) Image of surface glow of CdS/CNT cathode produced after 2 min (a) and 5 min (b,c) of synthesis and measured at the applied voltage of 7.5 V mm À1 (a,b) and 15 V mm À1 (c).

Photoluminescence of CdS nanoparticles grown on carbon nanotubes covered by a dielectric polymer layer

“…Luminescence of the deposited CdS could contribute to the background appearing in the scattering region ranging from 1000 to 2100 cm −1 . We had shown before that the intensity of the 1LO peak dramatically increases, and its width decreases during CdS synthesis in a chemical bath . This effect was attributed to improvement of the particle crystallinity in time.…”

Role of Defects in Carbon Nanotube Walls in Deposition of CdS Nanoparticles from a Chemical Bath

“…This suggestion was supported by transmission electron microscopy (TEM) analysis, which has detected the bigger CdS nanoparticles grown on the nanotube caps as compared to the nanoparticles formed on the nanotube sidewalls . Under applied electric field, the nanoparticles located at MWCNT tips emitted green light with an admixture of red and orange colors. , …”

“…11 Under applied electric field, the nanoparticles located at MWCNT tips emitted green light with an admixture of red and orange colors. 12,13 A chemical bath deposition (CBD) procedure, where a cadmium salt and thiourea are taken as sources of cadmium and sulfur ions, while ammonia works as a complexing agent and makes a basic medium for thiourea hydrolysis, is widely used for the formation of CdS thin films. 14,15 The structure and properties of deposited film depend on the temperature and duration of synthesis, 16,17 the type of cadmium salt, 18,19 the concentration and ratio of the reagents, 20,21 the pH of solution, 20,22 and the used substrate.…”

Optical properties of CdS quantum dots on graphene

“…Hybrid materials based on carbon materials and semiconductor nanoparticles (CdS [1][2][3][4][5][6][7][8][9][10][11], CdSe [12], CdTe [13], TiO 2 [14], nanodiamonds [15], etc.) are currently subject to extensive research, mainly with regard to their application in optoelectronics and power engineering.…”