New emerging rare-earth free yellow emitting 2D BCNO nanophosphor for white light emitting diodes

Abstract

We have demonstrated a new emerging rare-earth free highly-efficient two dimensional (2D) boron carbon oxynitride (BCNO) yellow emitting nanophosphor with high quantum efficiency for white light emitting diode (WLED) devices. This BCNO nanophosphor exhibits 2D layered structures analogous to hexagonal BN phase. Further, the EELS and XPS results confirm the nanophosphor consisted of B, C, N and O elements. The BCNO nanophosphor shows a broad highly intense yellow emission band centered at 580 nm corresponding to 470 nm excitation wavelength with a quantum efficiency approaching 89%. This novel nanophosphor with strong emission has subsequently been integrated to chip on board (CoB) based blue LEDs in order to fabricate WLEDs devices with a color rendering index of 92. Low color temperature (4899) and better CIE color coordinates (x = 0.3496, y = 0.3679) of a fabricated WLEDs device supports a 2D BCNO nanophosphor that could be an exceptional choice for CoB based WLEDs. Hence, our method provides a facile synthesis of rare-earth free 2D lightweight BCNO nanophosphor and its integration with CoB based blue LEDs for next generation advanced solid state white light applications.

Tunable luminescence from two dimensional BCNO nanophosphor for high-contrast cellular imaging

“…75-1681 are present in all powder samples. 4 These extraneous peaks are consequence of unreacted boric acid, as shown in our previous report. 4 The graphene-facilitated formation of h-BN has been observed and these overlapped signals indicate the hexagonal phase of 2D BCNO nanophosphor with lattice parameters, a ¼ 0.248 nm, b ¼ 0.248 nm and c ¼ 0.663 nm.…”

“…As we have previously reported, PEG is one of the appropriate carbon source materials for obtaining best PL intensity. 4 These materials were mixed in 120 gm of ultrapure water and stirred vigorously at 100 C for obtaining a clear transparent aqueous solution. Unless otherwise stated, the quantity of the boric acid and urea in the precursor solution were xed at 0.025 mol and 0.25 mol, respectively and the mole amount of PEG were changed from 0 to 0.35 mol.…”

“…Another material, well exploited due to its isoelectric resemblance with graphene is hexagonal boron nitride (h-BN). 4 The h-BN, a well-known conventional and non-toxic material has been used to provide better electrical insulation, high heat resistance and good lubricant properties. 5 The high corrosion resistance, high thermal conductivity, thermal stability under even oxygen atmosphere make h-BN a unique among other 2D members.…”

“…11 Recently, few works on the synthesis of BCNO phosphors by thermal catalytic CVD, solid-state reactions, microwave plasma CVD and one-step liquid process have been reported including its application in the white light emitting diodes (WLEDs). 4,11,25 In addition, hydrogen storage, electronic devices and electron eld-emission are some of the other attractive applications of BCNO. [15][16][17] Though, BCNO offers a wide range of advantages over phosphor, currently it is challenging to obtain the high purity BCNO nanomaterials.…”

“…Previously, we have reported the yellow colour emitting 2D BCNO nanophosphor for WLEDs applications. 4 Now, we are exploring the details of the synthesis of colour tunable 2D BCNO nanophosphor for in vitro and in vivo high-contrast cellular imaging.…”