High-stability lead-free tin(II)-perovskites by A-site cation engineering and surface-passivating engineering for high-performance hybrid bulk-heterojunction photodetectors

Tin-based perovskites have attracted more and more attention in recent years due to their non-toxic properties. However, the poor stability of Tin-based perovskites severely limits its further applications. In order to obtain more stable Tin-based perovskites, in this work, Cs ions are introduced as a precursor besides SnF₂ during the synthesis of Tin-based perovskites. Further, poly(N-vinylcarbazole) (PVK) is introduced into the above perovskites to improve the separation rate of photogenerated carriers and to suppress both O₂ and H₂O diffusion into Tin-perovskites. Enhanced-performance Tin-based perovskite photodetectors with hybrid bulk-heterojunctions were obtained, and our experimental data showed that the responsivity and the specific detectivity of the photodetectors ITO/ZnO/FA_0.9Cs_0.1SnBr₃:PVK/MoO₃/Ag reached to 409.8 A/W and 1.23 × 10¹⁴ Jones, respectively, under 25.3 μW/cm² 405 nm illumination at − 0.2 V. In addition, the devices also show great stability, whose photocurrent decreases only slightly after its deposing in glove box for 14 days. Thus, such a kind of combing A-site cation engineering with surface-passivating engineering on hybrid bulk-heterojunction provides a facile method for high-performance Tin-perovskite photodetectors with high-stability.