An alcohol soluble amino-functionalized organoplatinum(II) complex as the cathode interlayer for highly efficient polymer solar cells

A small-molecule amino-functionalized organoplatinum(II) complex Pt-N has been developed. The unique properties of Pt-N, including a well-defined chemical structure, an excellent solubility in environmentally friendly polar solvents and good electron extraction to high work-function metals, make it a promising candidate for cathode interfacial modification of solution processed multilayer polymer solar cells (PSCs). The resultant PSCs with an ITO/PEDOT: PSS/PTB7:PC71BM/interlayer/Al device configuration exhibited significantly improved efficiencies from 3.62% for an unmodified device to 8.89% by using a Pt-N cathode interlayer, benefiting from the dramatic enhancement in the open circuit voltage (0.53 V for bare Al PSCs to 0.75 V for Pt-N/Al PSCs), the fill factor (43.58% for bare Al PSC to 72.49% for Pt-N/Al PSC), and a slight increase in short-circuit current density. These results indicate that Pt-N is a new promising candidate as the cathode interlayer for highly efficient PSCs.