Magnetically tunable and stable deep-ultraviolet birefringent optics using two-dimensional hexagonal boron nitride

Salt‐Assisted Low‐Temperature Growth of 2D Bi2O2Se with Controlled Thickness for Electronics

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] In the past few years, 2D materials have been employed for the state-of-the-art electronic and optoelectronic devices. [14][15][16][17][18] Among the broad list of reported 2D materials, graphene is the most-prominent material due to its remarkably high carrier mobility. [19] However, the on/off switching in graphenebased field-effect transistors (FETs) is immensely difficult due to its zerobandgap.…”

Deep ultraviolet hydrogel based on 2D cobalt-doped titanate

“…In this work, by using specially synthesized low-cobaltdoped 2D CTO with a molar ratio of Co/Ti = 6%, the bandgap of the material increases to 3.9 eV, permitting the DUV transmittance and the consequent DUV modulation. Meanwhile, the optical anisotropy factor of 2D CTO is measured to be 1.5 × 10 -11 C 2 J −1 m −1 , which is larger than the highest reported value 34 , ensuring its extremely large Cotton-Mouton coefficient. Thanks to the sensitive magnetic response, the birefringent hydrogel is fabricated by crosslinking magnetically aligned 2D materials with the polymer matrix in a small magnetic field range of 0-0.8 T, and an ultra-low concentration of 2D material of 5 × 10 −4 vol%.…”

“…Compared to 1D material, two-dimensional (2D) material exhibits larger shape anisotropy (lateral size/thickness ratio is 10 2 -10 5 for 2D materials while length/diameter ratio is ~10 for 1D CdSe) and the resultant larger optical/magnetic/electrical anisotropy, making it highly sensitive to the external stimulus 30,31 and exhibiting strong light-matter interaction 32,33 . For instance, we recently discovered a giant magneto-birefringence effect in wide-bandgap 2D materials of cobalt-doped titanium oxide (CTO) and boron nitride, enabling the realization of DUV birefringent element due to the desired DUV stability and removal of DUV-absorptive/instable organic LC and ITO electrodes in the device structure 31,34 . Despite of the development of DUV LC modulator in boron nitride LC, inconvenient magnetic driving way, unclear and uncontrollable magnetic source of 2D boron nitride, as well as difficulty in exfoliating monolayer boron nitride, jointly calling for more research efforts to make this technology practically useful.…”

2D material inorganic liquid crystals for tunable deep UV light modulation

“…Recently, joint research [ 3 ] led by Bilu Liu of Tsinghua University, and Hui-Ming Cheng and Baofu Ding of the Chinese Academy of Sciences, involved the fabrication of a stable and magnetic-tunable deep UV light modulator using two-dimensional (2D) hexagonal boron nitride (h-BN) based inorganic liquid crystals, addressing the lack of transmissive light modulators in this deep UV region.…”

“…This milestone study is a breakthrough as it is the first time that h-BN liquid crystal devices have been used to tune deep UV light (Fig. 1 ) [ 3 ], creating numerous exciting opportunities ahead. It is not difficult to imagine that the widely used birefringence-tunable optics can be transferred from current visible and infrared regions to the technologically important deep UV region.…”