White‐Light Emission from an Integrated Upconversion Nanostructure: Toward Multicolor Displays Modulated by Laser Power

Abstract

The white backlight in displays is generated by optimizing the proportions of individual emitters with different wavelengths by variations in materials composition, phase, and structure. Color pixels usually result from the separation of white light or the excitation with multiwavelength or multipulse sources. However, it is a challenge to develop a material that comprises a single structure and emits over the full visible spectrum, but where the emission wavelengths can be controlled by a simple excitation source. Herein, we report an upconversion nanostructure that incorporates several lanthanide ions in the same core@shell@shell structure. The combination of multiple narrow spectral bands results in the emission of white light. The emission colors can be tuned by changing the excitation power density, which manipulates the photon transfer pathways. Applications such as flat-panel displays and imaging have been demonstrated.

La2O2SO4:RE/Yb new phosphors for near infrared to visible and near infrared upconversion luminescence (RE=Ho, Er, Tm)

“…While the downconversion (DC) luminescence of various RE activators in La 2 O 2 SO 4 , Y 2 O 2 SO 4 , and Gd 2 O 2 SO 4 were investigated before, the upconversion (UC) property of RE in oxysulfate has only scarcely been studied up‐to‐date. UC phosphors play essential roles when converting longer wavelength radiation into shorter wavelength luminescence is needed in the multi‐faceted areas of solid‐state lasers, multi‐color display, drug delivery, fluorescent biomedical application, and wavelength converters for solar cells . Though RE halides (such as β‐NaYF 4 :Er/Yb) are currently the most efficient and widely used UC phosphors, a very recent study by Chen et al found that Er 3+ also shows promising UC luminescence under Yb 3+ sensitization in Y 2 O 2 SO 4 .…”

(La0.97RE0.01Yb0.02)2O2S Nanophosphors Converted from Layered Hydroxyl Sulfate and Investigation of Upconversion Photoluminescence (RE=Ho, Er)

“…Upconversion (UC) phosphor is drawing considerable attention due to its unique ability to convert longer wavelength radiation into shorter wavelength fluorescence [1, 2] and is finding wide applications in the fields of solid-state lasers [3], multi-color displays [4], drug delivery [5], fluorescent biological labels [6], wavelength converters for solar cells [7], and so forth. A UC phosphor is commonly formed by doping a host lattice with a sensitizer/activator pair, where the sensitizer is usually Yb 3+ and the activator is frequently being Ho 3+ , Er 3+ , or Tm 3+ .…”

Physical Manipulation of Lanthanide‐Activated Photoluminescence

“…[2] Downshifting and quantum cutting belong to the conventional Stokes process where the emission energy is lower than the excitation energy. For example, multicolor emissions are expected for anti-counterfeiting, full-color display, and lighting, [23,24] red and near-infrared excitation and emissions are more suitable for biomedical treatment, [25,26] while ultraviolet, violet, and blue light are favored for photocatalysis and photovoltaic purposes. [3] The unique luminescent characteristics and energy transfer variety impart lanthanide materials great potentials in a wide range of fields, including but not limited to display and lighting, [4,5] laser, [6] information security, [7][8][9][10] sensing and detection, [11][12][13][14][15] biological imaging and therapy, [16][17][18] photocatalysis, and optoelectronic device.…”