In polymer and perovskite solar cells, interfacial materials between the active layer and the electrodes play a very important role. Such a buffer layer can prevent photo-generated carriers from recombination and tune the effective work function of electrodes as well as enhance the device stability. The most commonly used anode buffer layer, PEDOT:PSS, may cause some corrosion problems on ITO and thus affect the long-term stability of polymer and perovskite solar cells. Some transition metal oxides (TMOs), such as MoO3, V2O5, WO3 and NiO, are emerging as a promising class of alternatives for PEDOT:PSS as anode buffer layers and most of them are solution-processable. However, in order to prepare these TMOs layers both thermal annealing and toxic solvent are still needed, which is neither environmentally friendly nor economical. In this presention, I will talk about some some facial and green methods to fabricate inorganic and organic anode buffer layers for highly efficient polymer and perovskite solar cells at room temperature.