Preparation And Performance Of CIGS Solar Cells Of Absorption Layers Prepared By Powder Coating Method

Copper indium gallium selenide (CIGS) is a kind of direct bandgap semiconductor materials and has chalcopyrite structure, a high absorption coefficient (105cm-1), a wide range of broad spectrum and high stability. Therefore, CIGS attracts many researchers all over the world.In this thesis, the CIGS thin films were fabricated by paste coating. The manufacturing process is as follows:(1) preparing a precursor paste by ball-milling method, (2) pasting the thin precursor layer on the substrate, (3) exerting pressure to precursor layer before annealing, (4) annealing the precursor layer to form CIGS thin films at the atmosphere of Ar. Effect of different milling and annealing conditions on the properties of pastes and thin films were studied. Slurry particle size analyzer, X-ray diffraction (XRD), Field emission scanning electron microscope (FESEM), energy dispersive X-ray analysis (EDAX) and UV-vis spectrophotometer were used to investigate the particle size, structure, morphology and band gaps.With the increase of the ball-to-powder ratio and the ball milling time, the prepared thin films had the pure single-phase chalcopyrite structure. Diffraction peaks of XRD were intense and narrow with (112)、(400) and (316/332) preferred orientation, which indicated good crystallinity. The addition of 0.6ml polyethylene glycol, the reunion phenomenon had no obvious change with the incubation time increasing. Annealing 30min, the best thin films were fabricated at 500℃.Moreover, the properties of the thin films were also good. The precursor layers were exerted by the different pressures. It can be seen from the plan-view FESEM micrographs that the surfaces of these samples became more uniform and dense with the increase of pressure, The suitable pressure is 90 MPa. When annealing temperature was 500℃, the thin films had the appropriate optical properties.