Stable Room Temperature Thermoelectric Properties in a Supramolecular Assembly of an n‐Type Naphthalene‐diimide‐based Amphiphile

Abstract

Organic thermoelectric materials (OTEs) are in huge demand for their flexibility and robustness in applications of internet‐of‐things, wearables, and health monitoring devices. While choices of p‐type OTEs are widespread, there is still lack of stable (in air) n‐type systems to pair. Naphthalene‐diimides (NDIs), due to the presence of the planar‐structured electron‐deficient aromatic ring offer promising electron‐deficient building blocks to construct air‐stable n‐type semiconducting devices. Herein, an amphiphile derivative (cNDI‐1) is reported for two‐dimensional supramolecular assembly, and consequently TE measurements are carried out in a fully calibrated and standardised custom‐built Seebeck (S) set‐up. Promising S values (ca. −237 μV/K in THF and ca. −195 μV/K in water) are measured with a TE power factor of ∼0.05×10−5 μW/mK2 in THF and ∼0.6×10−5 μW/mK2 in water at room temperature. The study opens up the possibility of exploring broad range of molecular design library for newer n‐type OTEs.

Flexible Thermoelectric Generator from Bulk Graphite and Bismuth Traces on Emery Paper

“…Thermoelectric Properties and Output Performance Measurement: S of the samples was measured using vacuum-assisted custom-built Seebeck apparatus that was represented in detail in our previous work. [47] The traces drawn on the emery paper were cut into required dimension (10 mm  4 mm) before inserting it in the sample probe station of the apparatus. For temperature-dependent S measurement, both the heaters were utilized to maintain a constant temperature gradient (ΔT ) across the sample and temperature of both hot and cold ends were increased gradually to measure S from RT to 373 K (nearly).…”

Optimizing Output Performances in Stationery Papers–Based Hybrid Inorganic–Organic Flexible Thermoelectric Generators

“…Seebeck value of the TE elements was measured using vacuum‐assisted custom built apparatus that is reported previously in detail in our earlier works. [ 15,21 ] Four‐point probe method was used to measure electrical resistivity of the TE materials, in which Keithley SMU 2634B was used for sourcing current in outer two probes and measuring voltage in inner two probes using the formula , where, s was the distance between the two consecutive probes. [ 22 ] The resistivity ρ was divided with correction factor C = (2s T −1 ) ln2 to obtain corrected value of ρ (correction due to finite sample dimension), where T is thickness of the sample.…”

“…Detail measurement technique was reported in our earlier published work. [15,21] The error bars in the graphs represented the standard deviation value from three repeated measurements corresponding to each point and the particular point represented the average value.…”

High-Performance Paper-Based Thermoelectric Generator from Cu2SnS3 Nanocubes and Bulk-Traced Bismuth

“…For transport property measurements of both TE elements and the constructed TEG, we used the custom-built Seebeck apparatus and the four-probe conductivity measurement setup that have been reported previously. , The error bars in the graphs represent the standard deviation value from 10 repeated measurements, and the particular datum point represents the average value with approximate error from electrical measurement being 4–5% and the Seebeck measurement being 8–12%. To measure the output performance of the 20 p–n pair PTEG fabricated, a custom-built setup is used to provide a proper temperature gradient across the TEG device.…”