Abstract-Solution‐Processed Lead Iodide for Ultrafast All‐Optical Switching of Terahertz Photonic Devices

Manukumara Manjappa, Ankur Solanki, Abhishek Kumar,Tze Chien Sum, Ranjan Singh,

https://onlinelibrary.wiley.com/doi/abs/10.1002/adma.201901455


Solution‐processed lead iodide (PbI2) governs the charge transport characteristics in the hybrid metal halide perovskites. Besides being a precursor in enhancing the performance of perovskite solar cells, PbI2 alone offers remarkable optical and ultrasensitive photoresponsive properties that remain largely unexplored. Here, the photophysics and the ultrafast carrier dynamics of the solution processed PbI2 thin film is probed experimentally. A PbI2 integrated metamaterial photonic device with switchable picosecond time response at extremely low photoexcitation fluences is demonstrated. Further, findings show strongly confined terahertz field induced tailoring of sensitivity and switching time of the metamaterial resonances for different thicknesses of PbI2 thin film. The approach has two far reaching consequences: the first lead‐iodide‐based ultrafast photonic device and resonantly confined electromagnetic field tailored transient nonequilibrium dynamics of PbI2 which could also be applied to a broad range of semiconductors for designing on‐chip, ultrafast, all‐optical switchable photonic devices.

Abstract-Hybrid Lead Halide Perovskites for Ultrasensitive Photoactive Switching in Terahertz Metamaterial Devices

Manukumara Manjappa, Yogesh Kumar Srivastava, Ankur Solanki, Abhishek Kumar, Tze Chien Sum, Ranjan Singh

http://onlinelibrary.wiley.com/doi/10.1002/adma.201605881/abstract

The recent meteoric rise in the field of photovoltaics with the discovery of highly efficient solar-cell devices is inspired by solution-processed organic–inorganic lead halide perovskites that exhibit unprecedented light-to-electricity conversion efficiencies. The stunning performance of perovskites is attributed to their strong photoresponsive properties that are thoroughly utilized in designing excellent perovskite solar cells, light-emitting diodes, infrared lasers, and ultrafast photodetectors. However, optoelectronic application of halide perovskites in realizing highly efficient subwavelength photonic devices has remained a challenge. Here, the remarkable photoconductivity of organic–inorganic lead halide perovskites is exploited to demonstrate a hybrid perovskite–metamaterial device that shows extremely low power photoswitching of the metamaterial resonances in the terahertz part of the electromagnetic spectrum. Furthermore, a signature of a coupled phonon–metamaterial resonance is observed at higher pump powers, where the Fano resonance amplitude is extremely weak. In addition, a low threshold, dynamic control of the highly confined electric field intensity is also observed in the system, which could tremendously benefit the new generation of subwavelength photonic devices as active sensors, low threshold optically controlled lasers, and active nonlinear devices with enhanced functionalities in the infrared, optical, and the terahertz parts of the electromagnetic spectrum.