Manipulation of Crystal Orientation and Phase Distribution of Quasi-2D Perovskite through Synergistic Effect of Additive Doping and Spacer Engineering
Xiao Zhang, Lisanne M. Einhaus, Annemarie Huijser, Johan E. ten Elshof
Abstract
High Resolution Image Download MS PowerPoint Slide The diammonium precursor 1,4-phenylenedimethanammonium (PDMA) was used as a large organic spacer for the preparation of Dion–Jacobson-type quasi-2D perovskites (PDMA)(MA) n −1 Pb n I 3 n +1 (MA = methylammonium). Films with composition ⟨ n ⟩ = 5 comprised randomly orientated grains and multiple microstructural domains with locally differing n values. However, by mixing the Dion–Jacobson-type spacer PDMA and the Ruddlesden–Popper-type spacer propylammonium (PA), the crystal orientation in both the vertical and the horizonal directions became regulated. High crystallinity owing to well-matched interlayer distances was observed. Combining this spacer-engineering approach with the addition of methylammonium chloride (MACl) led to full vertical alignment of the crystal orientation. Moreover, the microstructural domains at the substrate interface changed from low- n ( n = 1, 2, 3) to high- n ( n = 4, 5), which may be beneficial for hole extraction at the interface between perovskite and hole transport layer due to a more finely tuned band alignment. Our work sheds light on manipulating the crystallization behavior of quasi-2D perovskite and further paves the way for highly stable and efficient perovskite devices.