(低温柔性甲脒锡碘钙钛矿太阳能电池新方法)Adv. Mater., 2017 (DIO 10.1002/adma.201606964)


2017-03-18
 

Multi-channel interdiffusion driven FASnI3 film formation using aqueous hybrid salt/polymer solutions toward flexible lead-free perovskite solar cells

Jun Xi,1 Zhaoxin Wu,1*,4 Bo Jiao,1,2 Hua Dong,1 Chenxin Ran,1 Chengcheng Piao,1 Ting Lei,1 Tze-Bin Song,2 Weijun Ke,2 Takamichi Yokoyama,2,3 Xun Hou,1 Mercouri G. Kanatzidis2*

 

 

Tin (Sn)-based perovskites are increasingly attractive because they offer lead-free alternatives in perovskite solar cells. However, depositing high-quality Sn-based perovskite films is still a challenge, particularly for low-temperature planar heterojunction (PHJ) devices. Here, we demonstrate a "multi-channel interdiffusion" protocol by annealing stacked layers of aqueous solution deposited formamidinium iodide (FAI)/polymer layer followed with an evaporated SnI2 layer to create uniform FASnI3 films. In this protocol, tiny FAI crystals, significantly inhibited by the introduced polymer, can offer multiple interdiffusion pathways for complete reaction with SnI2. What's more, water, rather than traditional aprotic organic solvents, is used to dissolve the precursors. Our best-performing FASnI3 PHJ solar cell assembled by this protocol exhibits a power conversion efficiency (PCE) of 3.98%. In addition, we demonstrate a flexible FASnI3-based flexible solar cell assembled on a polyethylene naphthalate (PEN)-ITO flexible substrate with a PCE of 3.12%. This novel interdiffusion process can help to further boost the performance of lead-free Sn-based perovskites.