• Bulletin of the Korean Chemical Society
• /
• v.33 no.9
• /
• pp.2910-2916
• /
• 2012

Cadmium sulphide (CdS) nanorods were prepared by a single precursor thermal decomposition (SPTD) method. The formation of CdS nanorods and their structure, morphology and elemental composition were studied by means of FT-IR, XRD, FE-SEM, HR-TEM and EDAX analysis. Photoluminescence (PL) and lifetime measurements were recorded to study the luminescence properties of the material. The PL spectrum of the CdS nanorods showed one broad peak and four shoulders and the cause for this emission was discussed. The PL emissions from the band edge and deep trap state of the CdS nanorods were studied by lifetime measurements. Further, the synthesized CdS nanorods showed an increase in efficiency of photocatalytic degradation of methylene blue (MB) and rhodamine B (RhB). The increase in the photocatalytic activity was attributed to the mixed phase of the CdS nanorods.

• New & Renewable Energy
• /
• v.1 no.1 s.1
• /
• pp.32-36
• /
• 2005

We studied the optoelectronic properties of hybrid solar cells formed by mixing cadmium sulfide [CdS] nanorods with a conjugated polymer, poly-2-methoxy, 5-[2'-ethy[hexyloxy]-1,4-p-phenylenevinylene[MEH-PPV]. CdS nanorods were grown vertically on Ti substrates by electrochemical deposition through a porous alumina template. Absorption spectrum of the composite layer was the same as the superposition of the absorption spectrum of each individual layer. The photoluminescence signal from MEH-PPV film was reduced as a result of the mixing. The energy conversion efficiency of MEH-PPV improved from $0.0012\%$ to about $0.60\%$ when combined with the vertically aligned CdS nanorods.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.5
• /
• pp.1118-1120
• /
• 2009

Micro-size CdS spheres of hollow shape were fabricated through the self-assembly of high density arrow-like nanorods. The synthesis of the CdS hollow spheres were accomplished in an aqueous solution of cadmium nitrate and triblock copolymer (Pluronic P123) at low temperature (80 ${^{\circ}C}$) through the slow release of S2- ions from thioacetamide. Morphology of the fabricated CdS hollow spheres was characterized by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The results indicate that the arrow-like CdS nanorods are simultaneously grown and attached each other to form the building units that become the spheres with hollow inside as a self-assembled process. The CdS spheres have a diameter of $2{\sim}3 {\mu}m$ and consist of the nanorods with a length of$\sim$800 nm. The nanocrystal building blocks have a hexagonal CdS structure.

• Korean Journal of Materials Research
• /
• v.28 no.5
• /
• pp.261-267
• /
• 2018

Hydrothermal synthesis of highly crystalline $TiO_2$ nanorods is a well-developed technique and the nanorods have been widely used as the template for growth of various core-shell nanorod structures. Magneli/CdS core-shell nanorod structures are fabricated for the photoelectrochemical cell (PEC) electrode to achieve enhanced carrier transport along the metallic magneli phase nanorod template. However, the long and thin $TiO_2$ nanorods may form a high resistance path to the electrons transferred from the CdS layer. $TiO_2$ nanorods synthesized are reduced to magneli phases, $TixO_{2x-1}$, by heat treatment in a hydrogen environment. Two types of magneli phase nanorods of $Ti_4O_7$ and $Ti_3O_5$ are synthesized. Structural morphology and X-ray diffraction analyses are carried out. CdS nano-films are deposited on the magneli nanorods for the main light absorption layer to form a photoanode, and the PEC performance is measured under simulated sunlight irradiation and compared with the conventional $TiO_2/CdS$ core-shell nanorod electrode. A higher photocurrent is observed from the stand-alone $Ti_3O_5/CdS$ core-shell nanorod structure in which the nanorods are grown on both sides of the seed layer.

• Journal of Electrical Engineering and Technology
• /
• v.7 no.6
• /
• pp.965-970
• /
• 2012

Structure and optical properties of cadmium sulphide-zinc oxide composite nanorods have been evaluated by suitable characterization techniques. The X-ray diffraction spectrum contains a series of peaks corresponding to reflections from various sets of lattice planes of hexagonal ZnO as well as CdS. The above observation is supported by the Micro-Raman spectroscopy result. The optical reflectance spectra of CdS-ZnO is compared with that of ZnO where we observe an enhanced absorption and hence diminished reflection from CdS-ZnO compared to that from only ZnO. A very small intensity of the visible photoluminescence peak observed at 550 nm proves that the ZnO nanorods have very low concentrations of point defects such as oxygen vacancies and zinc interstitials. The photocurrent in the visible region has been significantly enhanced due to deposition of CdS on the surface of the ZnO nanorods. CdS acts as a visible sensitizer because of its lower band gap compared to ZnO.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.2
• /
• pp.397-400
• /
• 2014

Size- and shape-controlled monodisperse wurtzite structured CdS nanorods have been successfully synthesized using a facile solution-based colloidal method. Depending on the control of injection/growth temperatures and the variation of Cd-to-S molar ratios, the morphology of the CdS nanocrystals (NCs) can be adjusted into bullet-like, rod-like, and dot-like shapes. X-ray diffraction (XRD), transition electron microscopy (TEM), and absorption spectroscopy were used to characterize the structure, morphology, and optical properties of as-synthesized CdS NCs. It was found that uniform CdS nanorods could be successfully synthesized when the injection and growth temperatures were very high (> $360^{\circ}C$). The aspect ratios of different shaped (bullet-like or rod-like) CdS NCs could be controlled by simply adjusting the molar ratios between Cd and S.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2010.02a
• /
• pp.57-57
• /
• 2010

Self assembled $Zn_{x-1}Cd_xS$ nanowires, synthesized on a Indium tin oxide coated glass substrate with low composition of Cd as x=0.09, were fabricated non-precursor via a co-evaporation method using of solid sources of CdS and ZnS. We studies that ZnCdS nanowires are dislocation-free and the single crystalline hexagonal wurtzite structure showed by transmission electron microscopy and selected area electron diffraction pattern. Cathode luminescence spectra showed an near band edge peak at 383nm originated from nanowires at 80K and 300K. Core level spectra of the Cd 3d, Zn 2p and S 2p in the ZnCdS nanorods were obtained by x-ray photoelectron spectroscopy. Prepared ZnCdS nanorods showed different shape with increase of substrate temperature at the growth.

• Macromolecular Research
• /
• v.17 no.12
• /
• pp.995-1002
• /
• 2009

Luminescent polynorbornene (PNB)/quantum dot (CdSe@ZnS; QD) composite nanorods and nanotubes were successfully prepared using anodic aluminum oxide (AAO) membranes of various pore sizes as templates. To protect QDs with high quantum yield from quenching during the phosphoric acid treatment used to remove the AAO templates, chemically stable and optically clear norbornene-maleic anhydride copolymers (P(NB-r-MA)) were employed as a capping agent for QDs. The amine-terminated QDs reacted with maleic anhydride moieties in P(NB-r-MA) to form PNB-grafted QDs. The chemical- and photo-stability of QDs encapsulated with PNB copolymers were investigated by photoluminescence (PL) spectroscopy. By varying the pore size of the AAO templates from 40 to 380 urn, PNB/QD composite nanorods or nanotubes were obtained with a good dispersion of QDs in the PNB matrix.

• Bulletin of the Korean Chemical Society
• /
• v.31 no.8
• /
• pp.2185-2189
• /
• 2010

Closely arranged CdSe and Zn doped CdSe vertical nanorod bundles were grown directly on FTO coated glass by using electrodeposition method. Structural analysis by XRD showed the hexagonal phase without any precipitates related to Zn. FE-SEM image showed end capped vertically aligned nanorods arranged closely. From the UV-vis transmittance spectra, band gap energy was found to vary between 1.94 and 1.98 eV due to the incorporation of Zn. Solar cell parameters were obtained by assembling photoelectrochemical cells using CdSe and CdSe:Zn photoanodes, Pt cathode and polysulfide (1M $Na_2S$ + 1M S + 1M NaOH) electrolyte. The efficiency was found to increase from 0.16 to 0.22 upon Zn doping. Electrochemical impedance spectra (EIS) indicate that the charge-transfer resistance on the FTO/CdSe/polysulfide interface was greater than on FTO/CdSe:Zn/polysulfide. Cyclic voltammetry results also indicate that the FTO/CdSe:Zn/polysulfide showed higher activity towards polysulfide redox reaction than that of FTO/CdSe/polysulfide.

• Korean Journal of Materials Research
• /
• v.30 no.3
• /
• pp.131-135
• /
• 2020

Silver nanowire (AgNW) networks have been adopted as a front electrode in Cu(In,Ga)Se2 (CIGS) thin film solar cells due to their low cost and compatibility with the solution process. When an AgNW network is applied to a CIGS thin film solar cell, reflection loss can increase because the CdS layer, with a relatively high refractive index (n ~ 2.5 at 550 nm), is exposed to air. To resolve the issue, we apply solution-processed ZnO nanorods to the AgNW network as an anti-reflective coating. To obtain high performance of the optical and electrical properties of the ZnO nanorod and AgNW network composite, we optimize the process parameters - the spin coating of AgNWs and the concentration of zinc nitrate and hexamethylene tetramine (HMT - to fabricate ZnO nanorods. We verify that 10 mM of zinc nitrate and HMT show the lowest reflectance and 10% cell efficiency increase when applied to CIGS thin film solar cells.