Study On Synthesis And Properties Of Cu-based Chalcogenide Photoelectrical Materials

CuInSe2 solar thin films have direct band gap structure, suitable band gap and improved efficiencies. And CuInSe2 solar thin films do not have light-induced degradation. It could maintain excellent photoelectric conversion efficiency for a long time. Co-reduction is a kind of technology which has simple process and cheap equipment. With this technology, the cost of CuInSe2 could be reduced effectively.In this research, the CuInSe2 powder were prepared by hydrothermal chemical co-reduction, the CuInSe2 films were prepared by spin-coating chemical co-reduction. In order to study the effects of raw materials, solvents, temperature and reaction time on the target product, the X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS) and Four-Point Probes were used in this research. The research mainly includes three parts, as follows:In the first part, CuInSe2 powder was synthesized by hydrothermal chemical co-reduction. When the raw materials are chlorides and reaction temperature above 180℃, the CuInSe2 phase were easily to be synthesized. The powder is irregular ball about 0.2μm in diameter, and the powder always agglomerates particles which about 1-3μm in diameter. When the raw materials are nitrates, the CuInSe2 phase was synthesized too. Its diffraction peaks are higher. Although the impurity is less but the agglomeration has not improved.In the second part, Cu-Se thin films were synthesized by spin-coating chemical co-reduction. When the raw materials are chlorides and reaction temperature between 200 "C to 220 ℃, the Cu-Se thin films were easily synthesized. The Cu-Se thin film was made up of flake-like grains about 1-2μm in diameter and ball-like grains about 0.3-0.5μm in diameter. When the reaction temperature is below 180℃, the main components of the film is NaCl. When the raw materials are nitrates, the Cu-Se thin film was synthesized too. When the reaction temperature is 200 ℃ and the reaction time is 20h, the diffraction peaks are high and sharp. The intensity of diffraction peaks is higher than which prepared by chloride. The Cu-Se thin film was made up of hexagonal flake-like grains about 2～3 μm in diameter and rod-like grains about 0.3～0.5μm in length. In addition, when the reaction time was prolonged to 40h, single phase CuSe has been synthesized. Prolonging reaction time was beneficial to the synthesis of CuSe.In the third part, CuInSe2 thin films were synthesized by spin-coating chemical co-reduction. When the raw materials are chlorides and reaction temperature was low, there was a lot of NaCl been prepared. When the reaction temperature was 380℃, the diffraction of NaCl was lower than before. With the reaction temperature increasing, the intensity of diffraction peaks of CuInSe2 became higher too. The thin film was made up of ball-like grains about 0.3-0.5μm in diameter and rod-like grains about 0.5μm in length. When the raw materials are nitrates, the NaN03 was less than before. Prolonging reaction time was beneficial to synthesis of CuInSe2. The thin film was made up of ball-like grains about 0.3-0.5μm in diameter. It was found in the research, immersing the film in distilled water could remove the NaCl effectively.