In last decade, number of papers studied effect of using many shapes/types of metamaterial surfaces to enhance light absorption in photovoltaic, I found many equations used in different papers, but I am not sure which one is correct for my research.

First equation used, calculate absorption using following formula, where R is reflection, and T is transmission.

Absorption = 1 - R - T

The problem here is, this is total absorption of (metal and active layer). absorption of metal is light losses, and the preferred one is active layer absorption. So I couldn't be sure if this enhanced absorption was for metal or active layer.

Second equation used, calculate absorption using first attached picture, where E is electric field inside photovoltaic active layer.

Here, we assume increase electric field increase absorption, however we didn't take effect of magnetic field intensity H in calculation. What I know is we need to maximazied energy absorbed not electric field, and energy equation of EMW include electric and magnetic field.

So I couldn't be sure if increasing electric filed in active layer will increase absorption without increasing or didn't change magnetic field?

Third equation used, calculate absorption using second attached picture, where E is electric field.

Here, similar defination as second equation.

I didn't take effect of magneric field H in equation to say that more energy absorbed and efficiency increase?

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-21-s3-a313

http://www.sciencedirect.com/science/article/pii/S0038092X16303772