Selenium metal flexible solar cell

Se, InSe, GaSe/CdS three solar cells pn junction thin films are deposited at room temperature on ITO glass and PET polymer flexible substrates by thermal evaporation technique at high vacuum pressure 2×10^-5 mbar. The X-Ray diffraction analysis showed that all are amorphous in nature while the as-deposited film CdS is polycrystalline. The optical energy gap and carrier concentration of Se, InSe, GaSe and CdS thin films are found 1.95eV, 1.6eV, 2.46eV and 2.4eV respectively with p=8.4×10⁹cm^-3, p=6.7×10¹¹cm^-3, p=1.2×10⁹cm^-3 and n=3.1×10¹³cm^-3 respectively. The four layers structure of solar cell formed by deposited CdS film with variable thickness t=200,300,550 nm on ITO conductive polyester film PET; R=15 (ohms per sq) with t=175 um or ITO deposited on glass 1mm thickness with deposited layers of Se, InSe and GaSe thin films in variable thickness t=700nm and 1000nm then Aluminum electrode as back surface. The results showed the efficiency decrease with increase thickness of thin films of semiconductors for CdS/InSe solar cell from %0.506 to %0.055 respectively, while we found efficiency solar cells increase when used ITO on Glass rather than ITO on PET substrate for pn junctions CdS/Se, CdS/InSe and CdS/GaSe from %0.377 to %0.355, %0.506 to %0.123 and %0.073 to %0.061 respectively.