Disorder-based Design Screening of a Semitransparent Ternary Organic/Silicon Four-Terminal Tandem Solar Cell

Ternary organic solar cells provide greater flexibility in controlling light absorption, molecular packing, phase separation, and charge transport. In this work, a MATLAB-based model is used to investigate a semitransparent D18:L8-BO:NVN organic top cell optically coupled to crystalline silicon in a four-terminal (4T) tandem configuration. The effects of NVN concentration (0–20%) and Ag rear-electrode thickness (3–15 nm) are evaluated over a defined parameter range. The highest calculated output is obtained at 20% NVN and an Ag thickness of 3 nm. Under these conditions, the top-cell power-conversion efficiency (PCE) reaches 17.95%, while the normalized silicon power contribution is 16.58%, giving a total 4T PCE of 34.53%. The average visible transmittance (AVT) is 67.16%, and the silicon short-circuit current density is 28.08 mA cm⁻². The corresponding light-utilization efficiency (LUE) and figure of merit (FOM) are 12.05 and 23.19, respectively. These results provide a comparative basis for design screening rather than a prediction of fabricated-device performance. Experimental validation using a matching semitransparent device is still required.