Highly stable three-band white light from an InGaN-based blue light-emitting diode chip precoated with (oxy)nitride green/red phosphors

Abstract

A three-band white light-emitting diode (LED) was fabricated using an InGaN-based blue LED chip that emits 455nm blue light, and green phosphor SrSi2O2N2:Eu and red phosphor CaSiN2:Ce that emit 538nm green and 642nm red emissions, respectively, when excited by the 455nm blue light. The luminous efficacy of this white LED is about 30lm∕W at a dc of 20mA. With increasing dc from 5.0to60mA, both the coordinates x and y of the white LED tend to be the same, and consequently the Tc is the same and the Ra increases to 92.2.

Investigation of 515nm green-light emission for full color emission LaAlO3 phosphor with varied valence Eu

“…A high-temperature solid-state synthesis procedure was employed to synthesize mix-valence Eu co-doped LaAlO 3 small amount of ethanol (A.R.) to form a slurry.…”

“…Multi-component phosphors with different visible light emissions are used to combine white light as excited by ultraviolet (UV) or blue light. For examples, the commonly used fluorescence lamp combines tri-color phosphors with mercury, and the recently arisen high color rendering index (CRI) white light emitting diode (LED) encapsulates green and red phosphors with InGaN blue chip [1][2][3][4][5]. Disadvantages, however, including light re-absorption among phosphor particles and complex blending operation usually lead to a decrease in the device efficiency for the colormix model.…”

Efficient and tuneable photoluminescent boehmite hybrid nanoplates lacking metal activator centres for single-phase white LEDs

“…Recently, solid-state phosphor white lightemitting diodes (WLEDs) have received considerable attention. WLED devices exhibit extra-long lifetime, excellent thermal resistance, higher luminous efficiency and lower power consumption compared to mercury-based fluorescent lamps [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] . There are at least three methods to generate white light in WLEDs: (i) the combination of three primary red, green and blue LEDs (RGB-WLED); (ii) the blue chip (450-470 nm)-pumped WLED (BLUE-WLED) and (iii) the near-ultraviolet chip (350-420 nm)-pumped WLED (ultraviolet WLED) [2][3][4] .…”

“…In ultraviolet-pumped WLEDs, multilayers of phosphors with distinct colour emission are generally used [14][15][16][17][18][19] . However, due to the reabsorption of light within the multicomponent phosphors, non-uniformity of luminescent properties with colour altering and a decrease of luminous efficiency are generally observed 2,20 .…”

Luminescent properties of red-emitting LiSr4B3O(9−3x/2)Nx:Eu2+ phosphor for white-LEDs

“…Nevertheless, the white light produced by this approach has serious drawbacks, such as high color temperature, poor CRI and lack of red light component [7,8], which restrict the more application of white LEDs. Alternatively, white light can also be produced by using a near-UV LED chip to pump a combination of red, green and blue light-emitting phosphors, giving relatively high CRI values [9]. Whereas, the efficiency of the currently applied red phosphors (Y 2 O 2 S:Eu 3 þ ) is much lower than that of the blue or green phosphors [10,11].…”