Optoelectronic Properties of Quasi‐Linear, Self‐Assembled Platinum Complexes: Pt–Pt Distance Dependence

Abstract Charge‐carrier mobilities of various self‐assembled platinum complexes were measured by time‐resolved microwave conductivity techniques in the temperature range –80 to +100 °C. Eight compounds were investigated in the present study, including the original Magnus' green salt ([Pt(NH₃)₄][PtCl₄]) and derivatives with the general structure [Pt(NH₂R)₄][PtCl₄], where R denotes an alkyl side chain. In one instance, the chlorines were substituted with bromines. For these complexes, which all consist of a linear backbone of platinum atoms with Pt–Pt distances, d, varying from 3.1 to ≥ 3.6 Å, a strong, inverse correlation was found between d and the one‐dimensional charge‐carrier mobility, Σμ_1D. The highest value of Σμ_1D at room temperature was observed for R = (S)‐3,7‐dimethyloctyl (dmoc) with Σμ_1D ≥ 0.06 cm² V^–1 s^–1. Almost all materials exhibited a charge‐carrier mobility that was relatively independent of the temperature over the range studied. One exceptional compound (R = (R)‐2‐ethylhexyl) showed a pronounced negative temperature dependence of the charge‐carrier mobility; upon decreasing the temperature from +100 °C to –80 °C the charge‐carrier mobility increased by a factor of about ten.