Cu(In,Ga)S 2 nanoparticles were synthesized by a hot-injection method under a low-vacuum ambience, which were printed and annealed with Se vapor for Cu(In,Ga)(S,Se) 2 solar cells. The Cu(In,Ga)S 2 nanoparticles were around 14 nm, and the stable ink was obtained by dispersing the nanoparticles in hexanethiol. The crystallinity of the Cu(In,Ga)(S,Se) 2 films increased with the increase in annealing temperature. Cu(In,Ga)(S,Se) 2 solar cells with KCN etching after annealing showed better photovoltaic properties than KCN etching before annealing and without etching. The best cell was observed at an annealing temperature of 540 ∘ C and KCN etching after annealing; the parameters of this cell were a short-circuit photocurrent density of 27.12 mA/cm 2 , open-circuit voltage of 0.42 V, fill factor of 0.38, and conversion efficiency of 4.3%.

The phosphorus barrier layers at the doping procedure of silicon wafers were fabricated using a spin-coating method with a mixture of silica-sol and tetramethylammonium hydroxide, which can be formed at the rear surface prior to the front phosphorus spin-on-demand (SOD) diffusion and directly annealed simultaneously with the front phosphorus layer. The optimization of coating thickness was obtained by changing the applied spin-coating speed; from 2,000 to 8,000 rpm. The CZ-Si p-type silicon solar cells were fabricated with/without using the rear silica-sol layer after taking the sheet resistance measurements, SIMS analysis, and SEM measurements of the silica-sol material evaluations into consideration. For the fabrication of solar cells, a spin-coating phosphorus source was used to form the n+ emitter and was then diffused at 930°C for 35 min. The out-gas diffusion of phosphorus could be completely prevented by spin-coated silica-sol film placed on the rear side of the wafers coated prior to the diffusion process. A roughly 2% improvement in the conversion efficiency was observed when silica-sol was utilized during the phosphorus diffusion step. These results can suggest that the silica-sol material can be an attractive candidate for low-cost and easily applicable spin-coating barrier for any masking purpose involving phosphorus diffusion.

Hot-injection synthesis of copper indium sulfide produces suitable ink for printed photovoltaic devices.