Physically Detachable and Operationally Stable Cs 2 SnI 6 Photodetector Arrays Integrated with µ-LEDs for Broadband Flexible Optical Systems

• Published in: Advanced materials (Weinheim) Vol. 34; no. 17; p. e2109673
• Main Authors: Krishnaiah, Mokurala, Kim, Seungyeob, Kumar, Ajit, Mishra, Dhananjay, Seo, Seung Gi, Jin, Sung Hun
• Format: Journal Article
• Language: English
• Published: Germany 01.04.2022
• Subjects: lead-free Cs 2SnI 6 perovskites; low-temperature charge transport; operational stability of photodetectors; detachable photodetector arrays with µ-LEDs; broadband photodetection arrays
• ISSN: 0935-9648; 1521-4095
• DOI: 10.1002/adma.202109673

With the surge in perovskite research, practical features for future applications are desired to be secured, but the reliability of the materials and the use of hazardous Pb are longstanding problems. Here, an air-stable Cs SnI (CSI) is prepared via diluted hydriodic acid solvent-based precursor optimization during scalable hydrothermal growth. Materials characterization is performed using various elemental peak analyses and crystallographic identification. The resulting CSI exhibits long-term operating stability over 6 months, i) at elevated temperatures, ii) in ambient air, and iii) under light illumination from UV to near-infrared. More importantly, to demonstrate an intriguing class of applications up to system level, physically detachable CSI photodetector arrays (PD-arrays), integrated with micro-light-emitting-diodes (μ-LEDs) arrays, are successfully fabricated. In addition, 3 × 3 flexible CSI PDs are fully operational, even in air, and their spatial uniformity in pixels is quantitatively evaluated. The charge-transport mechanisms of the CSI PDs under light and elevated temperature are assessed via temperature-dependent characterization from 148 to 373 K, implying the involvement of 3D variable-range hopping. Multicycle evaluation of the CSI PD-arrays confirms their operational stability in AC and DC modes, demonstrating this platform's potential benefit for wireless optical interconnection in advanced Si technology.