2,6-pyridinedimethanol (Py-diOH) is applied to the cathode interlayer in inverted polymer solar cells (PSCs) based on the blend of PTB7:PC71BM. A layer of Py-diOH generates a favorable interface dipole at the cathode interface. The power conversion efficiency of the devices with the interlayer reaches up to 7.44% with a J(sc) of 14.65 mA/cm(2), a V-oc of 0.71V, and a FF of 67.9%, respectively The PCE of the device with Py-2OH is very similar to that of the device with ZnO as the electron collection layer. It is possible to obtain high efficiency PSCs without any high temperature heat treatment.