摘要： In order to achieve efficient doping in polymer solar cell (PSC), the dopant needs to be selectively located in the binary components of bulk heterojunction (BHJ) film according to its polarity. The rarely studied n-type dopant is thoroughly examined in a simplified planar heterojunction (PHJ) device to address its favored location in the active layer. Results show that the n-dopant distributing in the acceptor layer or at the donor/acceptor interface produces enhanced device performance, whereas it harms the device when locating in the donor layer. Based on the results, the benefit of n-type doping is then transferred to the high-efficient BHJ devices via a sequential coating procedure. The performance improvement is closely linked with the variation of dopant’s location in the BHJ film, which is carefully examined by the synchrotron techniques with delicate chemical sensitivity. More interestingly, the sequential coating procedure can be easily extended to the p-doped device only by changing the dopant’s polarity in the middle layer. These findings pave the way of ambipolar doping in PSCs and make performance improvement by molecular doping within expectation.