Fan Zhang,Jun Song,Ming Chen,Junchen Liu,Yuying Hao,Yuncai Wang,Junle Qu,Pengju Zeng
Organic–inorganic metal halide perovskites have led to remarkable advancements in emerging photovoltaics. The rapid increase in the power conversion efficiency (PCE) of PSCs has been mainly achieved by improving perovskite morphology and crystallinity. Herein, we report a simple and effective means to improve perovskite grain sizes using a porous hole transport layer (i.e., PEDOT:PSS in this work). We used polystyrene nanospheres as a sacrificial template to fabricate the porous-PEDOT:PSS. The growth of the CH3NH3PbI3 perovskite film on the porous-PEDOT:PSS substrate yields a dramatic improvement in crystallinity and an enhancement in perovskite grain sizes. When the porous structure was applied as a hole transport layer in PSCs with planar heterojunction structures, the efficiency was significantly enhanced from 15.33% for the planar device to 17.32%. This simple method for enhancing perovskite morphology and crystallinity paves the way for its application to other device architectures for enhanced photovoltaic performance.
The electron/hole transport layer plays a very important role in the planar structure of perovskite solar cells. Conjugated polymers have received considerable attention for use in perovskite solar cells as hole/electron transport layers and passivation layers. Although the devices based on conjugated polymer hole transport layers have achieved much progress, their performance is still inferior to that of devices based on the conventional spiro-OMeTAD hole transport layer. Here, we investigated the solvent vapor annealing (SVA) effect on conjugated polymers as well as the corresponding perovskite solar cell devices. It was found that SVA treatment could enhance the hole charge carrier mobility and thin film crystallinity. Meanwhile, the charge transfer efficiency was enhanced, and charge recombination was reduced. Hence, the conjugated polymer based device exhibited comparable or even better performance compared with the conventional spiro-OMeTAD based device. Moreover, the device stability was also improved.