In situ growth of perovskite single-crystal thin films with low trap density

Developing in situ-grown perovskite single-crystal thin films (PeSCTFs) on transport layers is essential to achieve high-performance optoelectronic devices. However, it remains a challenge to grow PeSCTFs in situ with a high area-to-thickness ratio and low trap density. Here, we propose a new strategy of gradient heating nucleation and room-temperature growth. Gradient heating nucleation helps to overcome the high nucleation energy barrier and reduce the number of crystal nuclei, and room-temperature growth helps reduce the crystal growth rate and aims at an orderly deposition and diffusion of atoms for in situ growth of PeSCTFs with high quality. Consequently, the fabricated FAPbBr3 PeSCTF achieves a record area-to-thickness ratio of 1.84 × 105 mm and a low trap density of 3.76 × 108 cm−3. Moreover, the proposed strategy is also shown to be a universal method for in situ growth of other kinds of PeSCTFs on multiple transport layers. [Display omitted] •A crystal growth strategy for perovskite single-crystal thin films (PeSCTFs) is used•FAPbBr3 PeSCTFs achieve a low trap density of 3.76 × 108 cm−3•The FAPbBr3 PeSCTFs-based photodiode achieves an EQE of 94.2%•The strategy is a general method for various PeSCTFs on multiple transport layers Wang et al. propose a gradient heating nucleation and room-temperature growth method for in situ growth of perovskite single-crystal thin films (PeSCTFs) on multiple transport layers. The as-fabricated FAPbBr3 PeSCTFs with a record area-to-thickness ratio exhibit a record low trap density and high carrier mobility.