CdSe nanocrystals with a zinc blende structure allowed apparent Mg doping (∼9.8 at.%). Inverse micelles were formed at a low temperature as templates for the zinc blende CdSe nanocrystals, and paraffin oil and oleic acid were used as a solvent and a surfactant, respectively. The Mg doping was shown by energy dispersive x-ray spectroscopy (EDS) and inductively coupled plasma (ICP) atomic emission analyses. Although the particle size of the CdSe and Mg-doped CdSe nanocrystals were ∼6 and ∼8 nm, respectively, the Mg-doped ones show the obvious blueshift in the UV–visible absorption spectra due to the increase in the bulk energy bandgap, which is decisive evidence for the real Mg doping in the CdSe lattices. The Mg-doped CdSe nanocrystals also showed the blueshift in the photoluminescence (PL) spectra, and their PL intensity was comparable to or even higher than that of the undoped CdSe. This impurity doping using the zinc blende structure is suggested as a simple and effective way to tune the energy bandgap of CdSe nanocrystals and, in turn, to control their light emission colour.

High-density and single-crystalline CdS nanowires were grown on fluorine-doped tin oxide (FTO)/soda-lime glass substrates using Bi catalysts via the so-called solution-liquid-solid (SLS) mechanism. Through a series of voltage loading steps, high-quality Cu(In,Ga)Se 2 (CIGS) light absorption layers were electrochemically deposited on the CdS window layers and subsequently selenized at 400 °C to form photovoltaic cells. Due to the one dimensionality and single crystallinity of the CdS nanowires, the carrier collection efficiency could be improved. The resulting CIGS/CdS nanowire solar cells showed a light energy conversion efficiency of ∼6.18% under AM 1.5 conditions (I = 100 mW/cm 2 ), which is ∼28.7% higher than that of the equivalent CIGS solar cells containing chemically deposited CdS thin film as a window layer.

High-density and single-crystalline CdS nanowire arrays were formed on fluorine-doped tin oxide (FTO)coated soda-lime glass substrates without aid of templates at 220 °C. Bi was employed as a catalyst for the low-temperature growth of CdS nanowires via solution-liquid-solid (SLS) mechanism. CdS nanowires were very straight and they were ∼20-50 nm in diameter and ∼2-3 µm in length. CdS nanowires were in highly crystalline wurtzite structure, and their crystal growth direction was [001]. Careful controlling of processing conditions including Bi catalyst size, precursor concentration, and processing temperature was effective to grow thin CdS nanowires by suppressing formation of nanoparticles and radial growth of nanowires. Poly vinyl alcohol (PVA) film covering Bi catalyst layer played a critical role in holding Bi liquid droplets on the substrates during nanowire growth. The potential of CdS nanowire arrays on FTO/glass substrates was demonstrated to be used for organic-inorganic hybrid solar cells.

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