All-Inorganic Perovskite Nanosheet Fabrication under Synergistic Effect for Integrated Optoelectronics with Strong Light–Matter Interactions

Abstract

All-inorganic perovskites have emerged in the field of optoelectronic devices for their excellent light absorption and energy conversion efficiencies, as well as their superior stability compared to organic−inorganic perovskites. The two-dimensional (2D) all-inorganic perovskites have a higher exciton binding energy and carrier recombination efficiency than their bulk counterparts due to the quantum confinement effect, which indicts high strong light−matter interactions and is suitable for special integrated optoelectronics such as a micro laser or quick-response photodetector. However, it is difficult to fabricate a 2D large-sized sample with high crystal quality due to the nonlayered structure, which limits its further research and practical application. In this work, based on an atmospheric pressure chemical vapor deposition strategy combining a space-confined method and van der Waals epitaxy, the synergistic effect of these two techniques results in large-sized ultrathin all-inorganic CsPbI 3 perovskite nanosheets for which the lateral dimension can exceed 50 μm while the smallest thickness can reach 3 nm. The high crystal quality of the square-like samples has been confirmed by a microstructure characterization, while the corresponding performances like long carrier life (360 ns), high resistivity, and good stability were also verified, implying great promise for their applications in high-performance integrated optoelectronics. This method may pave the way for a uniform fabrication of other 2D nonlayered materials as well.

Excessive Iodine Enabled Ultrathin Inorganic Perovskite Growth at the Liquid‐Air Interface

“…This is reasonable because excessive I 2 can efficiently repair iodine vacancies of nanosheets, which can act as nonradiative recombination centers in iodine perovskites [23] . Correspondingly, Cs 3 Bi 2 I 9 nanosheets prepared with I 2 addition, even with ultrathin thickness, still own good environmental stability for about 10 days (Figure S6), as compared with others [24] . Interestingly, the addition of I 2 , with dual function in both liquid‐air interfacial growth and iodine vacancy repairation, can also be applied to other perovskites, such as Cs 3 Sb 2 I 9 (Figure S7).…”

“…[23] Correspondingly, Cs 3 Bi 2 I 9 nanosheets prepared with 2 addition, even with ultrathin thickness, still own good environmental stability for about 10 days (Figure S6), as compared with others. [24] Interestingly, the addition of I 2 , with dual function in both liquid-air interfacial growth and iodine vacancy repairation, can also be applied to other perovskites, such as Cs 3 Sb 2 I 9 (Figure S7). This further inspires us to fabricate vertical heterostructure of inorganic perovskites (Figure S8) by technique of picking up nanosheets from solution surface, as only achieved in 2D layered hybrid perovskites previously.…”

Excessive Iodine Enabled Ultrathin Inorganic Perovskite Growth at the Liquid‐Air Interface

“…[23] Correspondingly, Cs 3 Bi 2 I 9 nanosheets prepared with I 2 addition, even with ultrathin thickness, still own good environmental stability for about 10 days (Figure S6), as compared with others. [24] Interestingly, the addition of I 2 , with dual function in both liquid-air interfacial growth and iodine vacancy repairation, can also be applied to other perovskites, such as Cs 3 Sb 2 I 9 (Figure S7). This further inspires us to fabricate vertical heterostructure of inorganic perovskites (Figure S8) by technique of picking up nanosheets from solution surface, as only achieved in 2D layered hybrid perovskites previously.…”