The Study On Doping And Induced Crystallization Of Antimony Selenide Thin Film Solar Cells

Due to environmental and energy issues,we urgently need to develop sustainable clean energy,such as solar cells.Although silicon solar cells have become the mainstream products in the market,thin-film cells also have certain advantages due to their lightness,thinness and flexibility.At present,CIGS and Cd Te thin-film solar cells have achieved relatively high power conversion efficiency(PCE).However,the toxicity of Cd is a shortcoming of Cd Te solar cells,while In and Ga in CIGS are scarce and expensive.In the past few years,antimony selenide(Sb₂Se₃)thin film solar cells have attracted much attention.Sb₂Se₃ is an emerging photovoltaic material with superior photoelectric conversion performance.For example,it has the advantages of suitable band gap,high absorption coefficient,single-phase structure,inert grain boundary,low toxicity and low cost.In this paper,Pb I₂ was first used to effectively P-type doped Sb₂Se₃ film through thermal diffusion.After doping,the hole concentration increased from 1.6×10⁹ to 1.7×10¹³ cm^-3,and the resistivity decresed from 2.1×10⁸?cm to 2.9×10⁵?cm.These results indicate that Pb I₂is an effective P-type dopant for Sb₂Se₃.This article also uses Pb I₂ doping to improve the efficiency of Sb₂Se₃ thin film solar cells.The device structure used in this article is:ITO/Pb I₂doped Sb₂Se₃/C₆₀/Alq₃/Al.The results show that through Pb I₂ doping,the open circuit voltage of the device increases from 0.32 to 0.38V,and the power conversion efficiency increases from 2.87%to 4.43%.Secondly,the crystal quality of the Sb₂Se₃ film is improved by the method of inducing crystallization.After the introduction of the Alq₃ induction layer,the diffraction peak intensity of the(020)crystal plane was significantly increased,and the other diffraction peaks were weakened,indicating that the crystal orientation became more consistent.Secondary ion mass spectrometry and X-ray photoelectron spectroscopy tests show that Alq₃ molecules are decomposed during the annealing process,and the decomposed Al diffuses to the surface of the film.Al acts as a catalyst to improve the crystal quality of the Sb₂Se₃ film.This article also uses Alq₃ to induce crystallization to improve the efficiency of Sb₂Se₃ thin film solar cells.The device structure used in this article is:ITO/Alq₃/Sb₂Se₃/C₆₀/Alq₃/Al.The results show that after introducing the Alq₃ small molecule layer between ITO and Sb₂Se₃,the open circuit voltage of the device increases from 0.33 to 0.40V,and the conversion efficiency increases from 3.07%to 4.97%.