Resolution improvement in Haacke's figure of merit for transparent conductive films

The figures of merit (FOM) are tools that allow measuring the performance or effectiveness of procedures, systems, or devices. To evaluate transparent conductive films (TCF), the most widely used FOMs are Fraser & Cook (T/Rs) and Haacke (T-10/Rs). In both definitions, T refers to transmittance and Rs to the sheet resistance. In this work, we carry out an analysis of the advantages and disadvantages that each of these FOMs presents. We found that FOM Fraser & Cook exhibits a higher resolution than FOM Haacke. However, FOM Haacke surpasses FOM Fraser & Cook in the evaluation of transparent conductor materials. The latter because in FOM Haacke there is an implicit power function between T and Rs that allows a balanced treatment of T value against the value of Rs. Therefore, we proposed a slight modification to the FOM Haacke that improves its resolution by up to two orders of magnitude without altering its original essence; which is to give more value to the transmittance against the sheet resistance. We call this new expression FOM Haacke High Resolution. We show that FOM Haacke High Resolution can be used without loss of resolution at any intervals of transmittance and sheet resistance. Thus, it could be an excellent tool for intergroup comparisons of TCFs.