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Monolithic Flexible Vertical GaN Light‐Emitting Diodes for a Transparent Wireless Brain Optical Stimulator
Author(s) -
Lee Han Eol,
Choi JeHyuk,
Lee Seung Hyun,
Jeong Minju,
Shin Jung Ho,
Joe Daniel J.,
Kim DoHyun,
Kim Chang Wan,
Park Jung Hwan,
Lee Jae Hee,
Kim Daesoo,
Shin ChanSoo,
Lee Keon Jae
Publication year - 2018
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201800649
Subject(s) - light emitting diode , materials science , optoelectronics , diode , optical power , fabrication , flexible display , optics , nanotechnology , laser , layer (electronics) , medicine , physics , alternative medicine , pathology , thin film transistor
Flexible inorganic‐based micro light‐emitting diodes (µLEDs) are emerging as a significant technology for flexible displays, which is an important area for bilateral visual communication in the upcoming Internet of Things era. Conventional flexible lateral µLEDs have been investigated by several researchers, but still have significant issues of power consumption, thermal stability, lifetime, and light‐extraction efficiency on plastics. Here, high‐performance flexible vertical GaN light‐emitting diodes (LEDs) are demonstrated by silver nanowire networks and monolithic fabrication. Transparent, ultrathin GaN LED arrays adhere to a human fingernail and stably glow without any mechanical deformation. Experimental studies provide outstanding characteristics of the flexible vertical μLEDs (f‐VLEDs) with high optical power (30 mW mm −2 ), long lifetime (≈12 years), and good thermal/mechanical stability (100 000 bending/unbending cycles). The wireless light‐emitting system on the human skin is successfully realized by transferring the electrical power f‐VLED. Finally, the high‐density GaN f‐VLED arrays are inserted onto a living mouse cortex and operated without significant histological damage of brain.