High‐Efficiency Coordination Nanosheet Solar Cells Guided by Density Functional Theory and Drift–Diffusion–Poisson Modeling

ABSTRACT

Coordination nanosheets (CONASHs) with tunable compositions offer versatile platforms for solution‐processable photovoltaics (PV) by combining rational molecular design with efficient charge transport. Previously, we experimentally demonstrated that iron(II)‐benzenehexathiol (FeBHT) CONASH exhibits self‐powered photoresponsivity. Here, key material parameters, including band‐edge densities of states, dielectric constant, and balanced carrier mobilities, were obtained via density functional theory and used for drift–diffusion–Poisson modeling of a FeBHT‐based solar cell with the one‐dimensional solar cell capacitance simulator (SCAPS‐1D). Among the examined charge transporter combinations, the titanium dioxide (TiO ₂ ) electron transporter/2,2′,7,7′‐tetrakis( N , N ‐di‐p‐methoxyphenylamine)‐9,9′‐spirobifluorene (Spiro‐OMeTAD) hole transporter‐based solar cell exhibits the best performance, achieving a power conversion efficiency of up to 25.86%. Optimizing FeBHT thickness and doping raises the PCE to 31.87%, while defect tolerance maintains efficiencies above 26% under high defect densities. AC admittance and impedance analyses confirm efficient interfacial charge dynamics and reduced recombination.