Electrosprayed Polymer-Hybridized Multidoped ZnO MesoscopicNanocrystals Yield Highly Efficient and Stable Perovskite Solar Cells

摘要

Solid-state perovskite solar cells have been expeditiously developed since the past few years. However, there are a number of open questions and issues related to the perovskite devices, such as their long-term ambient stability and hysteresis in current density–voltage curves. We developed highly efficient and hysteresis-less perovskite devices by changing the frequently used TiO2 mesoscopic layer with polymer-hybridized multidoped ZnO nanocrystals in a common n–i–p structure for the first time. The gradual adjustment of ZnO conduction band position using single- and multidopant atoms will likely enhance the power conversion efficiency (PCE) from 8.26 to 13.54%, with PCEmax = 15.09%. The highest PCEavg of 13.54% was demonstrated by 2 atom % boron and 6 atom % fluorine co-doped (B, F:ZnO) nanolayers (using optimized film thickness of 160 nm) owing to their highest conductivity, carrier concentration, optical transmittance, and band-gap energy compared to other doped films. We also successfully apply a fine polyethylenimine thin layer on the doped ZnO nanolayers, causing the reduction in work functionand overall demonstrating the enhancement in PCE from ∼10.86%up to 16.20%. A polymer-mixed electron-transporting layer demonstratesthe remarkable PCEmax of 20.74% by decreasing the trapsites in the oxide layer that probably reduces the chances of carrierinterfacial recombination originated from traps and thus improvesthe device performance. Particularly, we produce these electron-richmultidoped ZnO nanolayers via electrospray technique, which is highlysuitable for the future development of perovskite solar cells.