Preparation And Properties Of Absorber Layer Of CIGS Thin Film Solar Cell

Chalcopyrite thin film CuInxGa1-xSe2(CIGS) polycrystalline compoundsemiconductor has draw the attention of researchers as a promising alternative tocrystalline silicon, a class of thin films exhibiting bandgap-tunable, high absorptioncoefficients and low cost for manufacturing. Although the best efficiencies to date havebeen produced using vacuum-based methods, they face challenges in commercialproduction due to their inherent cost-intensive equipments and large-scale incompatibility.In this work, doctor blade which is a non-vacuum printable ink-based deposition route hasbeen studied. The morphology, structures and optical-electrical properties of depositedfilms have been characterized by Scanning Electron Microscopy (SEM), EnergyDispersive X-Ray Spectroscopy (EDS), Auger electron Spectroscopy (AES), X-RayDiffraction (XRD), UV-vis spectrometer and four-point probe technique.Different stoichiometric ratio of Cu(NO3)2, Ga(NO3)3, In(NO3)3and SeCl4were usedas the resouce provided for CIGS. With ethanol, terpineol and ethyl cellulose as organicbinding agent adding into the solution, the viscosity and dispersiveness can be correctedfor the next coating step. It was found in the study that the residual of organic is severe,appropriate extend of heat insulation can alleviate this phenomenon. In the thin filmthrough relative long time high temperature treatment, a severe loss of selenium has beenobserved, however increasing the amout of SeCl4properly in the ink has been known as away to revise it.Different strichiometric ratio of Cu poor obsorber layer has been fabricated usingdoctor blade. Optimum ratio of Cu/(In+Ga)=0.8has been characterized with the sameconclusion of vacumm based co-evapration with best efficiency. This reveals thefeasibility of non-vacumm method for preparation of CIGS.A Gallium gradient CIGS absorber layer has been fabricated using multi-layer doctorblade. This was confirmed by AES deep profile.