The researchers published a study in Small in 2022. At present, perovskite solar cells can be roughly divided into two categories: upright (n-i-p) structure and inverted (p-i-n) structure. Inverted perovskite solar cells (PSCs) are known for their excellent device stability, simple structure, and low-temperature processing. However, disordered crystallization and bottom interface instability of perovskite films based on nickel oxide (NiO_x) substrates are still the main factors affecting the power conversion efficiency (PCE) of PSCs.

　　In this study, 2D perovskite with thiomorpholine 1,1-dioxide lead iodide (Td₂PbI₄) is introduced as a template to prepare 3D perovskite films with high crystal orientation and large grain size by a bottom-up growth method. By adding TdCl to the precursor solution, pre-crystallized 2D Td₂PbI₄ seeds can accumulate at the bottom interface, reducing the barrier to nucleation and providing a template for the growth of 3D perovskite films. Better (100) orientation and fewer defects during crystallization. In addition, the 2D Td₂PbI₄ on the bottom interface also hinders the redox reaction of the interface, reducing the hole extraction barrier on the buried interface. The results of the study found:

1. Td-0.5 PSC achieves 22.09% PCE and 1.16V open-circuit voltage.
2. In addition, the Td-0.5 PSC show extremely high stability, maintaining 84% of its initial PCE after 500 h of continuous irradiation under maximum power point operating conditions in N₂ atmosphere.

　　This work paves the way for improving the performance of inverted PSCs on NiO_x substrate.