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Graphene Sandwich Stable Perovskite Quantum-Dot Light-Emissive Ultrasensitive and Ultrafast Broadband Vertical Phototransistors
journal contribution
posted on 2019-10-18, 13:34 authored by Krishna
Prasad Bera, Golam Haider, Yu-Ting Huang, Pradip Kumar Roy, Christy Roshini Paul Inbaraj, Yu-Ming Liao, Hung-I Lin, Cheng-Hsin Lu, Chun Shen, Wan Y Shih, Wei-Heng Shih, Yang-Fang ChenDual-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
× 1010% with a photoresponsivity of >109 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.