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Using Preformed Meisenheimer Complexes as Dopants for n‐Type Organic Thermoelectrics with High Seebeck Coefficients and Power Factors
Author(s) -
Han Jinfeng,
Ganley Connor,
Hu Qin,
Zhao Xingang,
Clancy Paulette,
Russell Thomas P.,
Katz Howard E.
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202010567
Subject(s) - dopant , materials science , thermoelectric materials , seebeck coefficient , thermoelectric effect , doping , chemistry , inorganic chemistry , polymer chemistry , optoelectronics , thermodynamics , composite material , physics , thermal conductivity
A pre‐formed Meisenheimer complex of a naphthalenediimide (NDI) with tetrabutylammonium fluoride (TBAF) is obtained in a simple way by mixing dibrominated 4,9‐dibromo‐2,7‐bis(2‐octyldodecyl)benzo[lmn][3,8]phenanthroline‐1,3,6,8(2H,7H)‐tetraone and TBAF in solution and used as a dopant for n‐type organic thermoelectrics. Two n‐type polymers PNDIClTVT and PBDOPVTT are synthesized, n‐doped, and characterized as conductive and thermoelectric materials. PNDIClTVT doped with NDI‐TBAF presents a high σ value of 0.20 S cm –1 , a Seebeck coefficient ( S ) of −1854 µV K –1 , and a power factor (PF) of 67 µW m –1 K –2 , among the highest reported PF in solution‐processed conjugated n‐type polymer thermoelectrics. Using 4‐(1,3‐dimethyl‐2,3‐dihydro‐1H‐benzoimidazol‐2‐yl)phenyl)dimethylamine and NDI‐TBAF as co‐dopants, PNDIClTVT has a PF > 35 µW m –1 K –2 ; while for PBDOPVTT σ = 0.75 S cm –1 and PF = 58 µW m –1 K –2 . In this study it is found that an ionic adduct together with a neutral dopant improves the performance of n‐type organic thermoelectrics leading to an enhanced power factor, and more generally, the role of such an adduct in polymer doping is also elucidated.