Controlling the Film Microstructure in Organic Thermoelectrics

Doping is a vital method to increase the charge carrier concentration of conjugated polymers, thus improving the performance of organic electronic devices. However, the introduction of dopants may cause phase separation. The miscibility of dopants and polymers as well as the doping-induced microstructure change are always the barriers in the way to further enhance the thermoelectrical performance. Here, recent research studies about the influence of molecular doping on the microstructures of conjugated polymers are summarized, with an emphasis on the n-type doping. Highlighted topics include how to control the distribution and density of dopants within the conjugated polymers by modulating the polymer structure, dopant structure, and solution-processing method. The strong Coulombic interactions between dopants and polymers as well as the heterogeneous doping process of polymers can hinder the polymer film to achieve better miscibility of dopants/polymer and further loading of the charge carriers. Recent developments and breakthroughs provide guidance to control the film microstructures in the doping process and achieve high-performance thermoelectrical materials.

The Effect of Heterogeneous Doping on Transport Properties of Lanthanum Dimolybdate

A heterogeneous doping method was used for the first time to modify the transport properties of the oxygen-ion conductor La(2)Mo(2)O(9). The effect of temperature and oxygen partial pressure in the gas phase on conductivity of the obtained composite {0.85La2Mo2O9–0.15La2Mo3O12} was studied. Introduction of 15 mol. % an inert low-conductive additional phase La(2)Mo(3)O(12) results in an increase in conductivity of the matrix phase by nearly 1 orders of magnitude. It is associated with appearance of a composite effect. However, there is no suppression of the α-La(2)Mo(2)O(9)↔β-La(2) Mo(2)O(9) phase transition. It is shown that the conductivity type of both lanthanum dimolybdate and composite based on it is predominantly ionic in the wide range of oxygen partial pressures

The Effect of Simultaneous Homo- and Heterogeneous Doping on Transport Properties of Ba2In2O5

.