Photovoltaic technology based on conjugated polymer-fullerene composites continues to be of interest as a potential source of renewable energy. The advantages of polymer solar cells (PSCs) include low-cost fabrication via a simple coating or printing process, low specific weight, mechanical flexibility and versatility of chemical structure from advances in organic chemistry. The interfacial layers at both the cathode and anode play important roles in determining the final photovoltaic performance. Herein, we reported some hybrid interfacial materials applied in efficient PSCs. We have fabricated high-efficiency inverted PSCs with solution-processed ZnO-TiOx composite as the cathode interfacial layer. The resultant inverted cell based on PCDTBT:PC70BM blend demonstrated an FF of 0.67 and a PCE of 6.53%, much higher than those of the inverted cells with sole ZnO or TiOx interfacial layers. A second example is work-function tunable MoO3-Al composite film. The MoO3-Al composite films not only are highly transparent, but also possess tunable work functions dependent on the Al content in the composite, thus allowing it to be used as both the anode and cathode buffer layers to fabricate PSCs. Furthermore, the step-Al-doped MoO3 can be used as the interconnection layer to fabricate tandem PSCs. The third example is printable highly-conductive conjugated polymer sensitized ZnO cathode interfacial layer, which show superior performance even with increased thickness.