摘要
Perovskite solar cells(PSCs) have attracted great attention in recent years.And FTO/NiO/perovskite/PCBM/Ag(inverted PSCs) is one of the widely used architectures.We have designed and synthesized a series of n-type dopants to increase the conductivity and mobility of PCBM.With an extremely low doping ratio, the PCE of PSCs have improved from 16.6% to 18.1%.~([1]) However, the thermal stability of PSCs is still a major challenge for commercialization.We thoroughly investigated the thermal degradation process of the inverted structured PSCs induced by the silver electrode.Elemental depth profiles indicate that iodide and methylammonium ions diffuse through the electron-trasnporting layer and accumulate at the Ag inner surface.The driving force of forming AgI then facilitates the ions extraction.Variations on the morphology and current mapping of the MAPbI_3 thin films upon thermal treatment reveal that the loss of ions occurs at the grain boundaries and leads to the reconstruction of grain domains.Consequently, the deteriorated MAPbI_3 thin film, the poor electron extraction, and the generation of AgI barrier result in the degradation of efficiencies.These direct evidences provide in-depth understanding of the effect of thermal stress on the devices, offering both experimental support and theoretical guidance for the improvement on the thermal stability of the inverted PSCs.~([2])
Perovskite solar cells(PSCs) have attracted great attention in recent years.And FTO/NiO/perovskite/PCBM/Ag(inverted PSCs) is one of the widely used architectures.We have designed and synthesized a series of n-type dopants to increase the conductivity and mobility of PCBM.With an extremely low doping ratio, the PCE of PSCs have improved from 16.6% to 18.1%.~([1]) However, the thermal stability of PSCs is still a major challenge for commercialization.We thoroughly investigated the thermal degradation process of the inverted structured PSCs induced by the silver electrode.Elemental depth profiles indicate that iodide and methylammonium ions diffuse through the electron-trasnporting layer and accumulate at the Ag inner surface.The driving force of forming AgI then facilitates the ions extraction.Variations on the morphology and current mapping of the MAPbI_3 thin films upon thermal treatment reveal that the loss of ions occurs at the grain boundaries and leads to the reconstruction of grain domains.Consequently, the deteriorated MAPbI_3 thin film, the poor electron extraction, and the generation of AgI barrier result in the degradation of efficiencies.These direct evidences provide in-depth understanding of the effect of thermal stress on the devices, offering both experimental support and theoretical guidance for the improvement on the thermal stability of the inverted PSCs.~([2])
引文
[1]Z.Bin,J.Li,L.Wang,L.Duan,Energy Environ.Sci.2016,9,3424.
[2]J.Li,Q.Dong,N.Li,L.Wang,Adv.Energy Mater.2017,1602922.