Electroluminescence is a phenomenon where an electroluminescent material, typically phosphor, becomes excited and emits light upon exposure to an alternating current or an electrical field. Electroluminescent displays (EL displays) are a type of lighting application constructed based on this principle.
Compared to other display technologies that also utilize the principle of electroluminescence, EL displays are distinguished by their uniform light output, thin profile, flexibility, and durability.
![](https://res.cloudinary.com/dw7fqss5m/image/upload/f_auto,c_limit,w_3840,q_75/webflow/6334888a34bfac03b46aa715/663cc19506aec58d3943e452_Electroluminescent%20Displays%20%7C%20Voltera.webp)
![applications](https://res.cloudinary.com/dw7fqss5m/image/upload/f_auto,c_limit,w_128,q_75/voltera/images/applications/materials.webp)
APPLICABLE INDUSTRIES
- Advertising
- Consumer electronics
- Textile display
- Automotive
COMMON SUBSTRATES
- Blue-emitting phosphors (ZnS:Ag, ZnGa2O4, BaAl2S4:Eu2+)
- Yellow-emitting phosphors (ZnS:Mn)
- Green-emitting phosphors (ZnS:Cu, ZnGa2O4:Mn2+)
COMMON MATERIALS
- Polyethylene terephthalate (PET)
- Phosphatidylethanolamine (PE)
- Phosphatidylcholine (PC)
- Paper
- Glass
The 4 types of electroluminescent displays
Devices based on the principle of electroluminescence can be categorized into four types [1]:
- Organic or inorganic light-emitting diodes (OLEDs/LEDs)
- Powder phosphor devices
- Thin-film electroluminescent (TFEL) devices
- Thick-dielectric electroluminescent (TDEL) devices
While OLED, LED, and TFEL devices are most relevant in flexible electronics, our focus will be on TFEL devices.
Because they operate on similar principles, OLED, LED, and EL technologies are used in similar applications. These technologies are found in devices with smaller screens, such as smartphones, and larger screens, like TVs. EL displays are predominantly used for backlighting, a role that LEDs also perform in liquid crystal displays (LCD) screens [2].
Numerous researchers have attempted to incorporate EL displays and OLEDs into textile displays, including yarns, fabric, wearable art, sportswear, curtains, and furniture. However, their adoption has been primarily on a small scale, due to concerns about durability and flexibility [3] [4] [5].
![](https://res.cloudinary.com/dw7fqss5m/image/upload/f_auto,c_limit,w_3840,q_75/voltera/images/applications/head_up_display.webp)
Unique applications of electroluminescent displays
OLED, LED, and EL devices utilize different materials and have distinct structures. LEDs generate light through the electron-hole recombination in a semiconductor junction. OLEDs work similarly to LEDs but use organic compounds to produce light. EL displays emit light by exciting phosphor with an electric field.
EL displays serve different primary applications because of their unique properties. Primarily monochromatic, EL displays excel in applications where color variety is less critical than durability, flexibility, low power consumption, uniform light, and a wide viewing angle [6].
TFEL In-Plastic Head-up Display for Forklifts by Lumineq
Unique applications of electroluminescent displays
OLED, LED, and EL devices utilize different materials and have distinct structures. LEDs generate light through the electron-hole recombination in a semiconductor junction. OLEDs work similarly to LEDs but use organic compounds to produce light. EL displays emit light by exciting phosphor with an electric field.
EL displays serve different primary applications because of their unique properties. Primarily monochromatic, EL displays excel in applications where color variety is less critical than durability, flexibility, low power consumption, uniform light, and a wide viewing angle [6].
TFEL In-Plastic Head-up Display for Forklifts by Lumineq
![](https://res.cloudinary.com/dw7fqss5m/image/upload/f_auto,c_limit,w_3840,q_75/voltera/images/applications/head_up_display.webp)
![](https://res.cloudinary.com/dw7fqss5m/image/upload/f_auto,c_limit,w_3840,q_75/voltera/images/applications/night_vision.webp)
Challenges to expanding electroluminescent display applications
The color of the light in EL displays is tied to the chemical composition of the phosphor. Common combinations include:
- Blue: Zinc sulfide doped with silver (ZnS:Ag)
- Green: Zinc sulfide doped with copper (ZnS:Cu)
- Yellow-orange: Zinc sulfide doped with manganese (ZnS:Mn)
Researchers have investigated oxide phosphors such as ZnGa2O4 and ZnSiO4 for their excellent chemical and thermal stability and light emission capabilities [7] [8], but were challenged by more stringent manufacturing requirements [9].
A significant hurdle in advancing EL displays lies in achieving full-color displays. While some materials may excel in specific colors, finding a balanced combination that offers a bright, accurate, and enduring color spectrum remains a challenge.
Image: TEFL night vision devices by Lumineq
Challenges to expanding electroluminescent display applications
The color of the light in EL displays is tied to the chemical composition of the phosphor. Common combinations include:
- Blue: Zinc sulfide doped with silver (ZnS:Ag)
- Green: Zinc sulfide doped with copper (ZnS:Cu)
- Yellow-orange: Zinc sulfide doped with manganese (ZnS:Mn)
Researchers have investigated oxide phosphors such as ZnGa2O4 and ZnSiO4 for their excellent chemical and thermal stability and light emission capabilities [7] [8], but were challenged by more stringent manufacturing requirements [9].
A significant hurdle in advancing EL displays lies in achieving full-color displays. While some materials may excel in specific colors, finding a balanced combination that offers a bright, accurate, and enduring color spectrum remains a challenge.
Image: TEFL night vision devices by Lumineq
![](https://res.cloudinary.com/dw7fqss5m/image/upload/f_auto,c_limit,w_3840,q_75/voltera/images/applications/night_vision.webp)
![Printing Electroluminescent Ink on Paper and PET](https://res.cloudinary.com/dw7fqss5m/image/upload/f_auto,c_limit,w_1200,q_75/webflow/6334888a34bfac03b46aa715/664604094a7b91932cec6183_Printing%20Electroluminescent%20Ink%20on%20Paper%20and%20PET.webp)
Printing Electroluminescent Ink on Paper and PET
See how we printed an electroluminescent display on PET and paper using Saral’s conductive inks, phosphor ink, and dielectric ink — all on our NOVA dispensing platform.
![Electroluminescent](https://res.cloudinary.com/dw7fqss5m/image/upload/f_auto,c_limit,w_128,q_75/voltera/images/applications/brain_heart.webp)
The demand for smarter, more flexible, and bendable electronics, coupled with superior lighting capabilities, is expected to fuel the growth of EL display technology. As researchers and manufacturers continue to innovate within the realms of material science and fabrication techniques, the prospect of overcoming current limitations to wider use of EL display grows more tangible.
[1] Alexey N. Krasnov Electroluminescent displays: history and lessons learned, Displays, Volume 24, Issue 2, 2003, Pages 73-79, ISSN 0141-9382.
[2] Jeffrey Bausch LED vs. OLED, a comparison, 2015.
[3] Zhonglin Yang, Wenwen Wang, Jun Pan, Changhui Ye Alternating Current Electroluminescent Devices with Inorganic Phosphors for Deformable Displays, Cell Reports Physical Science, Volume 1, Issue.
[4] Janczak D, Zych M, Raczyński T, Dybowska-Sarapuk Ł, Pepłowski A, Krzemiński J, Sosna-Głębska A, Znajdek K, Sibiński M, Jakubowska M. Stretchable and Washable Electroluminescent Display Screen-Printed on Textile. Nanomaterials (Basel). 2019 Sep 7;9(9):1276. doi: 10.3390/nano9091276. PMID: 31500251; PMCID: PMC6781060.
[5] Kunigunde Cherenack, Koen van Os, Liesbeth van Pieterson Photonics Applied: Wearable Photonics: Smart Photonic Textiles Begin to Weave Their Magic, 2012.
[6] ELProCus Electroluminescent Display – Construction, Working, and Applications, n.d.
[7] Jorge Gil-Rostra, Francisco Yubero Valencia, Agustín R. González-Elipe Thin film electroluminescent device based on magnetron sputtered Tb doped ZnGa2O4 layers, Journal of Luminescence , Volume 228, 2020, 117617, ISSN 0022-2313.
[8] Tadatsugu Minami Oxide thin-film electroluminescent devices and materials, Solid-State Electronics, Volume 47, Issue 12, 2003, Pages 2237-2243, ISSN 0038-1101.
[9] Christopher N. King, Electroluminescent Displays, 2011+