Low‐Temperature Crystallized and Flexible 1D/3D Perovskite Heterostructure with Robust Flexibility and High EQE‐Bandwidth Product

• Published in: Advanced functional materials 2023-03, Vol.33 (12), p.n/a
• Main Authors: Qu, Wei, Li, Weijun, Feng, Xiaopeng, He, Yuhong, Pan, Wanting, Guo, KeKe, Li, Mingbian, Tan, Mingrui, Yang, Bai, Wei, Haotong
• Format: Article
• Language: English
• Subjects: 1D/3D flexible heterostructures; Bias; Cesium; Crystallization; CsPbI 3; Flexibility; Heterostructures; high EQE‐bandwidth products; High gain; Low noise; low‐temperature crystallization; Materials science; Optoelectronics; Perovskites; Phase stability; Phase transitions; Photometers; Quantum efficiency; Substrates
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202213955

All‐inorganic perovskite cesium lead triiodide (CsPbI3) has attracted much attention among the perovskite family due to its excellent optoelectronic properties and chemical stability. However, the high‐temperature crystallization process makes CsPbI3 less compatible with commercially flexible substrates, limiting its application into flexible optoelectronics. Here, a cation of 1‐(3‐aminopropyl)‐2pyrrolidinone (APP) is reported that can form 1D (APP)PbI3 perovskite as templates, and significantly reduce the CsPbI3 black‐phase transition energy with a low annealing temperature of 75 °C, which further enables a flexible (APP)PbI3/γ‐CsPbI3 (1D/3D) heterostructure photodetector on ITO/PET substrate. A high external quantum efficiency (EQE) greater than 2377% is observed along the orientated 1D/3D heterostructure. The high gain and low noise result in a high specific detectivity (D*) over 1012 Jones under −0.6 V low bias. The optimized device structure brings a high EQE × bandwidth product of 119 kHz under a low driving bias. Due to the high toughness of orientated APP+ ions and the face‐connected [PbI3]− chains structure as a strong energy absorber, the flexible photodetector also shows excellent phase stability and impressive flexibility, remaining >90% initial responsivity after over 20 000 times bending with potential flexible imaging application in harsh environments. γ‐CsPbI3 thin film is prepared through a low‐temperature annealing process achieved by 1D perovskite template (APP)PbI3. Flexible (APP)PbI3/CsPbI3 1D/3D heterostructure photodetectors with robust flexibility are fabricated successfully. Gain property is generated because of the electron injection caused by trap states at PEDOT: PSS/CsPbI3 interface. The detectors show huge potential in flexible detection and imaging with excellent stability.