Solution-processed Cu(In,Ga)(Se,S) 2 solar cells prepared via a surface sulfurization process
Journal
Journal of the Taiwan Institute of Chemical Engineers
Journal Volume
110
Pages
41-50
Date Issued
2020
Author(s)
Abstract
The photovoltaic (PV) characteristics of solution-coated Cu(In,Ga)Se2 films were effectively improved via a surface sulfurization in this study to overcome the complexity to control the appropriated amounts of sulfur ionsduring the sulfurization process.After sulfurization treatment, the Cu(In,Ga)(Se,S)2 films with double-graded band gap were obtained because the incorporation of sulfur-ion intoCu(In,Ga)Se2 films increasedthe band gap near the surface region.The formation of selenium vacancies in Cu(In,Ga)(Se,S)2 films were effectively diminished by adjusting H2S concentration. Band gap gradients and defect passivation reduced the interface recombination and improved the carrier collection in the devices. As the H2S concentration was raised from 0 to 1.0 vol%, the open-circuit voltage was increased from 541 to 596 mV, thereby boosting the conversion efficiency from 10.71to 12.40%. The reduction of vacancy defects and surface roughness suppressed the formation of shunt paths, resulting ina decrease indiode factor and leakage current. Compared with the Cu(In,Ga)(Se,S)2 films deriving from vacuum processes, solution-coated Cu(In,Ga)(Se,S)2 films with relatively small grains facilitated the sulfur diffusion along the grain boundaries into the films.Therefore, the appropriate H2S concentration used in the solution-coated Cu(In,Ga)(Se,S)2 films was less than vacuum processes. This investigation demonstrates that adjusting the concentrationof H2S is vital for enhancing the PV properties of thesolution-processed Cu(In,Ga)(Se,S)2 PV cells. © 2020 Taiwan Institute of Chemical Engineers
Subjects
Atomic force microscopy; CIGS solar cell; Grain growth; Photovoltaic performance; SIMS analysis; Sulfurization
SDGs
Other Subjects
Atomic force microscopy; Copper compounds; Energy gap; Gallium compounds; Grain boundaries; Grain growth; Open circuit voltage; Photovoltaic cells; Solar cells; Solar power generation; Sulfur; Surface roughness; CIGS solar cells; Cu(In ,Ga)Se2 films; Interface recombination; Photovoltaic performance; Sims analysis; Solution-processed; Sulfurization; Surface sulfurization; Selenium compounds
Type
journal article