Power Factor Enhancement in Solution‐Processed Organic n‐Type Thermoelectrics Through Molecular Design

Abstract

A new class of high-performance n-type organic thermoelectric materials, self-doping perylene diimide derivatives with modified side chains, is reported. These materials achieve the highest n-type thermoelectric performance of solution-processed organic materials reported to date, with power factors as high as 1.4 μW/mK(2). These results demonstrate that molecular design is a promising strategy for enhancing organic thermoelectric performance.

Photoinduced p‐ to n‐type Switching in Thermoelectric Polymer‐Carbon Nanotube Composites

“…[3][4][5][6] One key advantage of this class of materials is their amenability to solution processing, and thus potential for roll-to-roll upscaling. [ 7,8 ] The fully lowcost potential relies, however, on achieving realistic performance while keeping the processing schemes simple, including patterning of different materials.…”

“…For example, extrinsic doping of an n-type polymer in vacuum has proven to be ineffi cient due to large scale phase segregation. [ 6 ] A more direct, molecular design approach of the side chains of a small molecule has shown potential, [ 5 ] exhibiting good performance inside a glovebox. Another promising n-type material are CNTs, which are intrinsically ambipolar when protected from air, and have been shown to work as both p-type and n-type thermoelectric materials.…”

“…0.01 µW m −1 K −2 for this work). [ 5,6 ] Since the presented method is likely to be applicable to other materials systems, we expect that signifi cantly higher effi ciencies can be reached by selecting better performing materials like semiconducting single-walled carbon nanotubes, and appropriate dopants, [ 53 ] while keeping processing complexity low by depositing a minimum number of layers and selecting a suitable transformation step like the UV-irradiation presented here, or other simple methods, like vapor printing. [ 54 ] Besides performance, stability is also a key parameter since most reported n-type organic materials are not stable in air.…”

The impact of trans/cis photoisomerization on photoinduced electron transport between 4,4′-stilbenedicarboxylic acid and columnar perylenediimide aggregates in water

“…Materials PDI-I was synthesized according to the reported method [33], and the details were presented in the supplementary material. Purification of water was performed with a Molecule Lab Water Purifier (Gene 1810D), and the ultrapure water (>18.2 MΩ cm, 25°C) was used in all experiments.…”

Progress in Polymer Thermoelectrics

“…But, in the past 5 years, the number of reports, devoted to n-type organic materials, is steadily growing. It was found that promising materials are n-type fullerenes K x C70 [44], fullerenes C60 doped with Cr 2 (hpp) [46], self-doped perylene diimides (PDI) [47], polyethylenimine (PEI)/diethylenetriamine (DETA)-doped CNT, that were further reduced by NaBH4 [48], poly(p-phenylene vinylene) derivatives (FBDPPV) doped with Table 2. Thermoelectric properties of selected n-type organic semiconductors.…”