Blended Conjugated Host and Unconjugated Dopant Polymers Towards N‐type All‐Polymer Conductors and High‐ZT Thermoelectrics

Abstract

N‐Type thermoelectrics typically consist of small molecule dopant+polymer host. Only a few polymer dopant+polymer host systems have been reported, and these have lower thermoelectric parameters. N‐type polymers with high crystallinity and order are generally used for high‐conductivity ( σ ${\sigma }$ ) organic conductors. Few n‐type polymers with only short‐range lamellar stacking for high‐conductivity materials have been reported. Here, we describe an n‐type short‐range lamellar‐stacked all‐polymer thermoelectric system with highest σ ${\sigma }$ of 78 S−1, power factor (PF) of 163 μW m−1 K−2, and maximum Figure of merit (ZT) of 0.53 at room temperature with a dopant/host ratio of 75 wt%. The minor effect of polymer dopant on the molecular arrangement of conjugated polymer PDPIN at high ratios, high doping capability, high Seebeck coefficient (S) absolute values relative to σ ${\sigma }$ , and atypical decreased thermal conductivity ( κ ${\kappa }$ ) with increased doping ratio contribute to the promising performance.

Pyrazinacene conjugated polymers: a breakthrough in synthesis and unraveling the conjugation continuum

“…These pyrazinacene polymers hold great promise across a wide range of applications, including organic electronics, energy conversion and storage, electrochemical transistors, catalysis, and sensors. 68–75 Additionally, they help to narrow the gap between number of p-type and n-type polymers.…”

Advanced Thermoelectric Textiles for Power Generation: Principles, Design, and Manufacturing

“…A summary of TE properties of TE materials near room temperature and some underneath working principles underneath TE enhancement [ 23,40,41 ] over the past decade: a) power factor (PF) and b) thermoelectric figure of merit ( zT ). [ 34,41–81 ] Inset images: Thermoelectric parameter coupling and grain boundary scattering: reproduced with permission. [ 40 ] Copyright 2021, Elsevier; and ion/electron thermal potential: reproduced with permission.…”

Copolymers Based on π-Conjugated Asymmetric Naphthalene Diimide Building Blocks: Synthesis, Crystallography, and Structure–Property–Charge Transport/Photovoltaic Correlations

“…N-type (electron-transporting) conjugated polymers are essential components in diverse organic optoelectronic device technologies − such as all-polymer solar cells (APSCs), − thermoelectric generators, − n-type organic field-effect transistors (OFETs), , and others, , and for these reasons have been extensively studied over the past two decades. − N-type polymers based on the naphthalene diimide ( NDI ) acceptor unit are among the most investigated with poly­[ N , N ′-bis­(2-octyldodecyl)-naphthalene-1,4,5,8-bis­(dicarboximide)-2,6-diyl]- alt -5,5′-(2,2′-bithiophene) ( PNDITh2 or N2200 ) being the most prominent example, exhibiting an impressive electron mobility surpassing 6 cm 2 /(V s), low energetic disorder, and enabling APSC power conversion efficiencies >10%. − Since N2200 exhibits an important optoelectronic performance, several NDI -based donor–acceptor (D-A) copolymers with regioregular (RR) and regioirregular (RI) architectures have been developed. − However, NDI polymers achieved via/comprising an asymmetric NDI building block have not been reported to date due to limited synthetic protocols . Asymmetric structures generate local dipoles that can enhance interactions between neighboring molecules, hence favoring charge transport − as well as photovoltaic performance for several organic semiconductors. − Conventional Stille polycondensation reactions using dibrominated NDI building blocks and bis­(trialkylstannyl) aryl units as the starting materials have been the primary synthetic method for preparing NDI polymers; however, this approach is not particularly sustainable and using two symmetric building blocks only generates symmetric NDI polymers. , Kiriy and co-workers have developed an effective alternative polymerization protocol in which 2,6-di­(bromoaryl) substituted NDI units (Br-Het- NDI -Het-Br) are polymerized using activated zinc, which avoids the use of toxic stannanes.…”