Graphene Sandwich Stable Perovskite Quantum-Dot Light-Emissive Ultrasensitive and Ultrafast Broadband Vertical Phototransistors

Abstract

Dual-functional devices that can simultaneously detect light and emit light have a tremendous appeal for multiple applications, including displays, sensors, defense, and high-speed optical communication. Despite the tremendous efforts of scientists, the progress of integration of a phototransistor, where the built-in electric field separates the photogenerated excitons, and a light-emitting diode, where the radiative recombination can be enhanced by band offset, into a single device remains a challenge. Combining the superior properties of perovskite quantum dots (PQDs) and graphene, here we report a light-emissive, ultrasensitive, ultrafast, and broadband vertical phototransistor that can simultaneously act as an efficient photodetector and light emitter within a single device. The estimated value of the external quantum efficiency of the vertical phototransistor is ∼1.2 × 10 10 % with a photoresponsivity of >10 9 A W −1 and a response time of <50 μs, which exceed all the presently reported vertical phototransistor devices. We also demonstrate that the modulation of the Dirac point of graphene efficiently tunes both amplitude and polarity of the photocurrent. The device exhibits a green emission having a quantum efficiency of 5.6%. The moisture-insensitive and environmentally stable, light-emissive, ultrafast, and ultrasensitive broadband phototransistor creates a useful route for dual-functional optoelectronic devices.

Charge transfer between lead halide perovskite nanocrystals and single-walled carbon nanotubes

“…33 Chen and colleagues recently reported graphene sandwich stable PNC light-emissive ultrasensitive and ultrafast broadband phototransistors. 34 Herein, we report a detailed electron transfer study using single-walled CNTs and methylammonium lead halide PNCs. The preference of single-walled CNTs over C 60 fullerene is due to their superior electron transfer properties.…”

Oxidized eutectic gallium–indium (EGaIn) nanoparticles for broadband light response in a graphene-based photodetector

“…A time constant of about 3 ms is obtained, which is at least one order of magnitude faster than that of generally reported hybrid graphene-quantum dot photodetector. [25][26][27] The detectivity is also measured and calculated, and its value is about 3.8×10 9 cmHz 1/2 W -1 .…”

“…[22][23][24] However, the discrete energy structure of quantum dots makes its light absorption band narrow, which has limits for broadband detection. There is some work to improve the response of quantum-dot based devices, [25][26][27] but the performance in responsivity, response speed and response band generally cannot be optimized at the same time, and designed complex structure also increase difficulty for the fabrication and application, so much efforts is still needed.…”

Recent Progress of Quantum Dot‐Based Photonic Devices and Systems: A Comprehensive Review of Materials, Devices, and Applications

“…For example, Bera et al reported light‐emissive vertical phototransistors based on perovskite QD and graphene, which can perform as broadband photodetector and light emitter within a single device ( Figure ). [ 186 ] High‐performance perovskite QDs acted as both exciton generator and recombination centers, which allowed the photodetection and the light emission, simultaneously, resulting in the EQE of 1.2 × 10 10 %, a photo‐responsivity of >10 9 A W −1 , and a response time of 20 μs. In addition, the device demonstrated a green emission with a quantum efficiency of 5.6%.…”