Wanting Li,Shiqi Wei,Duankai Wu,Peng Zhang,Guoliang Chen,Binbin Luo,Xiongling Yu,Zhenyu Huang,Feiming Li
2D/3D multidimensional perovskite heterostructures have attracted considerable attention due to their inherent stability and efficient charge transport. However, many challenges remain in fabricating stable 2D/3D multidimensional perovskite heterostructures, such as a precise and convenient pathway to control the perovskite phase with stable interfacial interactions between the 2D and 3D perovskite layers. Therefore, developing a convenient method for the construction of 2D/3D perovskite heterostructures is highly necessary. In this study, we have successfully synthesized stable 2D/3D multidimensional (PEA)2PbBr4 perovskite heterostructures by precisely modulating post cation exchange with cesium oleate (CsOA). As CsOA increased, 2D (PEA)2PbBr4 nanosheets gradually transformed into 3D CsPbBr3, resulting in a multidimensional 2D/3D heterostructure with vivid multi-emission changes. Taking advantage of this precise control process, we explored their potential application in the fluorescent colorimetric detection of Cs+ in soybean oil based on multidimension transformation of 2D (PEA)2PbBr4 nanosheets. This novel strategy not only provides a new approach to constructing 2D/3D perovskite heterostructures but also expands the visual detection strategies for Cs+ sensing.
Xupeng Gao,Xinyu Shen,Dingke Xue,Xin Li,Po Lu,Min Lu,Chunyan Li,William W. Yu,Xue Bai
Two-dimensional (2D) perovskites have become a research hotspot due to their large exciton binding energy and excellent stability. However, it is difficult to achieve longer wavelength emission than blue and green light in the 2D perovskites owing to their wide band gap resulting from their strong quantum confinement. Herein, we demonstrate a simple, efficient and low energy consumption crystallization method at room temperature to synthesize Mn2+ ion doped 2D (PEA)2PbBr4 nanocrystals (NCs) with dual-color emission centered at 410 nm from the exciton transition of the host and 600 nm from the d–d transition of Mn2+ ions. The periodic XRD peaks prove the formation of 2D perovskites. It is reassuring that the high PLQY of 54% has been achieved in the Mn2+ ion doped 2D (PEA)2PbBr4 NCs. The temperature-dependent and time-resolved spectra illustrate the efficient energy transfer from excitons to Mn2+ dopant ions. The realization of white LEDs with different color temperatures presents an opportunity and prospect for Mn2+ ion doped 2D perovskites in LED application.
Metal halide perovskite (MHP) single crystals have shown great potential for high-performance X-ray detection due to their excellent carrier transport properties, tunable optical bandgap, and low-temperature fabrication process. However, 3D perovskite single crystals suffer from severe ion migration, limiting the stability and sensitivity of X-ray detectors. Herein, a lowing temperature crystallization (LTC) method for liquid-phase epitaxial growth of 2D (PEA) 2 PbBr 4 single-crystal (SC) film on 3D CsPbBr 3 substrate is demonstratedand a 2D/3D (PEA) 2 PbBr 4 /CsPbBr 3 SC heterojunction is successfully constructed. The epitaxial (PEA) 2 PbBr 4 layer shows a pronounced passivation effect on CsPbBr 3 SC with a low trap density of 2.27 × 10 10 cm −3 . As such, the prepared 2D/3D heterojunction X-ray detector achieves a record-low detectable dose rate of 3.05 nGy air s −1 and high sensitivity of 34496 µC Gy air −1 cm −2 in 120 keV hard X-ray detection, with a largely suppressed dark current drift of 2.49 × 10 −4 nA cm −1 s −1 V −1 . In addition, the heterojunction detector exhibits a self-driven sensitivity of 44 µC Gy air −1 cm −2 due to its built-in electric field. This work provides a simple strategy to controllable construct 2D/3D MHP SC heterojunction with excellent optoelectronic characteristic, which is conducive to promoting the development of MHP SC X-ray detectors and other optoelectronic devices.
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