Comment on “Introduction of a Novel Figure of Merit for the Assessment of Transparent Conductive Electrodes in Photovoltaics: Exact and Approximate Form”

Abstract

Anand et al. introduce an implicit equation for transparent conductive electrode (TCE) merit in photovoltaics (PV) by lumping series resistance in with the diode. However, an explicit equation has been previously derived by lumping series resistance external to the diode. For TCEs of practical interest for PV, the choice of where to lump series resistance does not affect merit, so external lumping is preferred. On the other hand, monolith deadspace, metal grid shadowing, and grid resistance shift TCE merit away from the figure of merit behavior published by Anand et al.

Response to Christopher P. Muzzillo's Comments on “Introduction of a Novel Figure of Merit for the Assessment of Transparent Conductive Electrodes in Photovoltaics: Exact and Approximate Form”

“…Muzzillo mentioned his figure of merit to be a good approximation to our exact FOM (or φ Anand ) in case there were no module geometries or additional metal grids to be considered. [12] Looking at his formulas and the involved approximations we found a simple way to approach the exact FOM even closer by simply considering the limitation of the photocurrent by the TCE (compare with equation 1) also for the correction done on the maximum power point voltage (compare with Equation 2):…”

“…In fact, Muzzillo's FOM is based on a few earlier works as indicated by himself. [12] Although Muzzillo's figure of merit (Equation 3) is claimed to be an explicit FOM, the calculation of current density and voltage at the maximum power point requires solving the Shockley equation as well, which is the very implicit equation we are using for our exact FOM. Thus, to verify φ Muzzillo , we numerically solved the implicit Shockley equation to derive the current-voltage curve, which then was evaluated for the current density and voltage at the maximum powerpoint.…”

“…As indicated in our original work, we were intended to only consider effects directly arising from the physical properties of the TCE itself, namely its transmittance and its sheet resistance. However, as shown by Muzzillo and us before, [12,13] the impact of the geometric fill factor is readily added by a prefactor considering the ratio between the solar cell length over the sum of the solar cell length and the solar cell distance (dead space). Following his suggestion, we simply added this prefactor for comparison by considering the serial interconnection due to some finite solar cell distance.…”

Cracked Film Lithography with CuGaOx Buffers for Bifacial CdTe Photovoltaics

“…[20] This is because CFL can pattern wires with widths down to 2 µmlarge enough to avoid fast degradation, [21,22] yet narrow enough to be spaced extremely close to one another (10 µm) while remaining highly transparent. [23] CFL is performed by suspending nanoparticles (e.g., TiO 2 or poly(methyl methacrylate) (PMMA)) in solution and coating that suspension on a substrate (Figure 1). Here we use spin-coating, but blade and spray coating have been demonstrated with these suspensions.…”