Cobalt dopant with deep redox potential for organometal halide hybrid solar cells.
In this work, we report a new cobalt(III) complex, tris[2-(1H-pyrazol-1-yl)pyrimidine]cobalt(III) tris[bis(trifluoromethylsulfonyl)imide] (MY11), with deep redox potential (1.27 V vs NHE) as dopant for 2,2',7,7'-tetrakis-(N,N-di-p-methoxyphenylamine)-9,9'-spirobifluorene (spiro-OMeTAD). This dopant possesses, to the best of our knowledge, the deepest redox potential among all cobalt-based dopants used in solar cell applications, allowing it to dope a wide range of hole-conductors. We demonstrate the tuning of redox potential of the Co dopant by incorporating pyrimidine moiety in the ligand. We characterize the optical and electrochemical properties of the newly synthesized dopant and show impressive spiro-to-spiro(+) conversion. Lastly, we fabricate high efficiency perovskite-based solar cells using MY11 as dopant for molecular hole-conductor, spiro-OMeTAD, to reveal the impact of this dopant in photovoltaic performance. An overall power conversion efficiency of 12% is achieved using MY11 as p-type dopant to spiro-OMeTAD.
Energy Research Institute @ NTU (ERI@N), Nanyang Technological University, Research Techno Plaza, Singapore 637553 (Singapore); School of Materials Science & Engineering, Nanyang Technological University, Singapore 639798 (Singapore).
Teck Ming
TM
Koh
Sabba
S
Dharani
Hairong
H
Li
Rajiv Ramanujam
RR
Prabhakar
Nripan
N
Mathews
Andrew C
AC
Grimsdale
Subodh G
SG
Mhaisalkar
D003035:Cobalt / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D011211:Electric Power Supplies; D004563:Electrochemistry; D006219:Halogens / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D012993:Solar Energy
D056831:Coordination Complexes; D006219:Halogens; D009942:Organometallic Compounds; D003035:Cobalt
cobalt complex; dye-sensitized solar cells; electrochemistry; perovskites; redox potential