Aluminum‐doped Zn1 − xMgxO as transparent conductive oxide of Cu(In, Ga)(S, Se)2‐based solar cell for minimizing surface carrier recombination. (21st June 2017)

• Record Type: Journal Article
• Authors: Chantana, Jakapan; Kato, Takuya; Sugimoto, Hiroki; Minemoto, Takashi
• Is Part Of: Progress in photovoltaics. Volume 25:Number 12(2017)
• Page Start: 996
• Page End: 1004
• Publication Date: 2017-06-21
• Subjects: (Cd, Zn)S -- Cu(In, Ga)(S, Se)2 -- [Mg]/([Mg] + [Zn]) ratio -- thin‐film solar cell -- Zn1 − xMgxO -- Zn1 − xMgxO:Al; Solar cells -- Periodicals; Photovoltaic cells -- Periodicals; Solar power plants -- Periodicals; 621.31245
• DOI: 10.1002/pip.2911
• Languages: English
• ISSNs: 1062-7995

Abstract

Abstract: A 19.5%‐efficient Cu(In, Ga)(S, Se)2 (CIGSSe)‐based solar cell is obtained by replacing traditional CdS/ZnO buffer layers with Cd0.75 Zn0.25 S/Zn0.79 Mg0.21 O buffer layers for increasing short‐circuit current density because band‐gap energies of Cd0.75 Zn0.25 S and Zn0.79 Mg0.21 O are wider than those of CdS and ZnO, respectively. This yields the increase in external quantum efficiency in a short wavelength range of approximately 320 to 550 nm. Moreover, difference of conduction band minimum ( E C ) between Zn1 − x Mg x O:Al (transparent conductive oxide, TCO) layer and CIGSSe absorber is optimized by varying [Mg]/([Mg] + [Zn]), x . It is revealed that Zn1 − x Mg x O:Al films with [Mg]/([Mg] + [Zn]) in a range of 0.10 to 0.12, enhancing E g from 3.72 to 3.76 eV, are appropriate as TCO because of their enhanced mobility and decreased carrier density. Addition of 12% Mg into ZnO:Al to form Zn0.88 Mg0.12 O:Al as TCO layer effectively decreases surface carrier recombination and improves photovoltaic parameters, especially open‐circuit voltage and fill factor. This is the first experimental proof of the concept for optimizing E C difference between TCO and absorber to minimize surface carrier recombination. Ultimately, conversion efficiency ( η ) of CIGSSe solar cell with alternative Cd0.75 Zn0.25 S/Zn0.79 Mg0.21 O/Zn0.88 Mg0.12 O:Al (TCO) layers is enhanced to 20.6%, owing to control of total E C alignment, which is higher η up to 12.6% relative as compared with the solar cell with traditional CdS/ZnO/ZnO:Al layers. Abstract : Difference of conduction band minimum ( E C ) between Zn1 − x Mg x O:Al (transparent conductive oxide; TCO) layer and Cu(In, Ga)(S, Se)2 (CIGSSe) absorber is optimized by varying [Mg]/([Mg] + [Zn]), x . Addition of 12% Mg into ZnO:Al to form Zn0.88 Mg0.12 O:Al as TCO layer effectively decreases surface carrier recombination and improves photovoltaic parameters. Ultimately, conversion efficiency of CIGSSe solar cell with Cd0.75 Zn0.25 S/Zn0.79 Mg0.21 O/Zn0.88 Mg0.12 O:Al (TCO) layers is enhanced to 20.6% owing to control of total E C alignment in the device.