Highly enhanced long time stability of perovskite solar cells by involving a hydrophobic hole modification layer

In this work, Nd-doped TiOx by pulsed laser deposition and hydrophobic ZnPc by rotary vacuum thermal evaporation were firstly employed as electron and hole transport layers to improve the PSC performance. Such improvement lends crucial support to the enhanced injection and extraction of photo-generated carriers at the electron transport layer/perovskite interface and hole transport layer/perovskite interface, which sequentially trigger remarkable increases in Jsc and Voc. More importantly, the hole modification layer ZnPc could also prevent moisture permeation into the perovskite photoactive layer, improving the long-term stability of PSCs. After optimization, the device exhibits an optimum PCE of 16.8% and the long-term stability (91% of initial PCE remains after 2400 h), which is the best report for PSCs in ambient environment without any sealing until now. Furthermore, large area device (225 mm2) and flexible devices were also fabricated for demonstrating the potential practical application prospects. This work offers novel insights on the PSC devices with respect to high permanence and long-term stability.292