• Ji, X.
• Stoeckel, M-A
• Hallani, Rk
• Puttisong, Y.
• Rivnay, J.
• Strzalka, J.
• Alsufyani, M.
• Tian, J.
• Paulsen, Bd
• Mcculloch, I.
• Fabiano, S.
• Combe, C.
• Regeta, K.
• Chen, X.
• Thorely, K.
• Meli, D.

Abstract

Three lactone-based rigid semiconducting polymers were designed to overcome major limitations in the development of n-type organic thermoelectrics, namely electrical conductivity and air stability. Experimental and theoretical investigations demonstrated that increasing the lactone group density by increasing the benzene content from 0 % benzene (P-0), to 50 % (P-50), and 75 % (P-75) resulted in progressively larger electron affinities (up to 4.37 eV), suggesting a more favorable doping process, when employing (N-DMBI) as the dopant. Larger polaron delocalization was also evident, due to the more planarized conformation, which is proposed to lead to a lower hopping energy barrier. As a consequence, the electrical conductivity increased by three orders of magnitude, to achieve values of up to 12 S cm and Power factors of 13.2 μWm−1 K−2 were thereby enabled. These findings present new insights into material design guidelines for the future development of air stable n-type organic thermoelectrics.

Topics

• density
• impedance spectroscopy
• polymer
• electrical conductivity