Relationship between Material Properties and Transparent Heater Performance for Both Bulk-like and Percolative Nanostructured Networks

Abstract

Transparent heaters are important for many applications and in the future are likely to be fabricated from thin, conducting, nanostructured networks. However, the electrical properties of such networks are almost always controlled by percolative effects.The impact of percolation on heating effects has not been considered and the material parameter combinations which lead to efficient performance are not known. In fact, figures of merit for transparent heaters have not been elucidated, either in bulk-like or percolative systems. Here, we develop a simple yet comprehensive model describing the operation of transparent heaters. By considering the balance of Joule heating versus power dissipated by both convection and radiation, we derive an expression for the time-dependent heater temperature as a function of both electrical and thermal parameters. This equation can be modified to describe the relationship between temperature, optical transmittance and electrical/thermal parameters in both bulk-like and percolative systems. By performing experiments on silver nanowire networks, systems known to display both bulk-like and percolative regimes, we show the model to describe real systems extremely well. This work shows the performance of transparent heaters in the percolative regime to be significantly less efficient compared to the bulk-like regime, implying the diameter of the nanowires making up the network to be critical. The model allows the identification of figures of merit for networks in both bulk-like and percolative regimes. We show that metallic nanowire networks are most promising, closely followed by CVD graphene with networks of solutionprocessed graphene and carbon nanotubes being much less efficient.

Metallic nanowire networks: effects of thermal annealing on electrical resistance

“…19,20 It has been suggested recently that a second instabil-ity may also be observed due to Joule heating when metallic nanowire networks are used with current densities similar to those found in a solar cell of ≈10% efficiency, leading to electrode failure in a matter of days. 21 29,30 In this work, we studied the effects of thermal annealing on the electrical properties of AgNW networks. The main goal is to better understand their behaviour and to optimize the electrical properties of the annealed network.…”

A highly flexible transparent conductive electrode based on nanomaterials

“…The infrared images inset in the voltage-temperature (V-T) graph of Figure 2e show the temperature variation of rGO/ CNT/AgNW coating step by step with increasing input voltage. Using the V-T data, the temperature variation at the steady state as a function of areal power density (the power applied by Joule heating per unit area) 27 for all the coatings based on the AgNW layer with different combinations of protective layers, such as rGO and CNTs, can be compared, as shown in Supplementary Figure S7.…”

Electrochemical Investigation of the Growth of Copper Nanowires in the Presence of Ethylenediamine through Mixed Potential

“…28 This agrees well with the widely accepted theory on percolation networks which explains that the probability of nanowires to form junctions drastically increases at higher concentrations of nanowires. [28][29][30][31] This is because a single nanowire can connect several other nanowires across the surface.…”