Thermophotonics for ultra-high efficiency visible LEDs
The wall-plug efficiency of modern light-emitting diodes (LEDs) has far surpassed all other forms of lighting and is expected to improve further as the lifetime cost of a luminaire is today dominated by the cost of energy. The drive towards higher efficiency inevitably opens the question about the l...
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| Format: | Article |
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SPIE-Intl Soc Optical Eng
2018
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| Online Access: | http://hdl.handle.net/1721.1/116357 https://orcid.org/0000-0003-0420-2235 |
| _version_ | 1826202026442227712 |
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| author | Ram, Rajeev J |
| author2 | Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science |
| author_facet | Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Ram, Rajeev J |
| author_sort | Ram, Rajeev J |
| collection | MIT |
| description | The wall-plug efficiency of modern light-emitting diodes (LEDs) has far surpassed all other forms of lighting and is expected to improve further as the lifetime cost of a luminaire is today dominated by the cost of energy. The drive towards higher efficiency inevitably opens the question about the limits of future enhancement. Here, we investigate thermoelectric pumping as a means for improving efficiency in wide-bandgap GaN based LEDs. A forward biased diode can work as a heat pump, which pumps lattice heat into the electrons injected into the active region via the Peltier effect. We experimentally demonstrate a thermally enhanced 450 nm GaN LED, in which nearly fourfold light output power is achieved at 615 K (compared to 295 K room temperature operation), with virtually no reduction in the wall-plug efficiency at bias V < hω/q. This result suggests the possibility of removing bulky heat sinks in high power LED products. A review of recent high-efficiency GaN LEDs suggests that Peltier thermal pumping plays a more important role in a wide range of modern LED structures that previously thought - opening a path to even higher efficiencies and lower lifetime costs for future lighting. |
| first_indexed | 2024-09-23T12:00:50Z |
| format | Article |
| id | mit-1721.1/116357 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T12:00:50Z |
| publishDate | 2018 |
| publisher | SPIE-Intl Soc Optical Eng |
| record_format | dspace |
| spelling | mit-1721.1/1163572022-09-27T23:31:25Z Thermophotonics for ultra-high efficiency visible LEDs Ram, Rajeev J Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Ram, Rajeev J The wall-plug efficiency of modern light-emitting diodes (LEDs) has far surpassed all other forms of lighting and is expected to improve further as the lifetime cost of a luminaire is today dominated by the cost of energy. The drive towards higher efficiency inevitably opens the question about the limits of future enhancement. Here, we investigate thermoelectric pumping as a means for improving efficiency in wide-bandgap GaN based LEDs. A forward biased diode can work as a heat pump, which pumps lattice heat into the electrons injected into the active region via the Peltier effect. We experimentally demonstrate a thermally enhanced 450 nm GaN LED, in which nearly fourfold light output power is achieved at 615 K (compared to 295 K room temperature operation), with virtually no reduction in the wall-plug efficiency at bias V < hω/q. This result suggests the possibility of removing bulky heat sinks in high power LED products. A review of recent high-efficiency GaN LEDs suggests that Peltier thermal pumping plays a more important role in a wide range of modern LED structures that previously thought - opening a path to even higher efficiencies and lower lifetime costs for future lighting. MIT Bose Fellowship Program 2018-06-18T14:59:08Z 2018-06-18T14:59:08Z 2017-02 2018-03-16T19:12:16Z Article http://purl.org/eprint/type/ConferencePaper 0277-786X http://hdl.handle.net/1721.1/116357 Ram, Rajeev J. “ Thermophotonics for Ultra-High Efficiency Visible LEDs .” Edited by Jong Kyu Kim, Michael R. Krames, Li-Wei Tu, and Martin Strassburg. Light-Emitting Diodes: Materials, Devices, and Applications for Solid State Lighting XXI (February 16, 2017). https://orcid.org/0000-0003-0420-2235 http://dx.doi.org/10.1117/12.2251373 Proceedings of SPIE--the Society of Photo-Optical Instrumentation Engineers Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf SPIE-Intl Soc Optical Eng SPIE |
| spellingShingle | Ram, Rajeev J Thermophotonics for ultra-high efficiency visible LEDs |
| title | Thermophotonics for ultra-high efficiency visible LEDs |
| title_full | Thermophotonics for ultra-high efficiency visible LEDs |
| title_fullStr | Thermophotonics for ultra-high efficiency visible LEDs |
| title_full_unstemmed | Thermophotonics for ultra-high efficiency visible LEDs |
| title_short | Thermophotonics for ultra-high efficiency visible LEDs |
| title_sort | thermophotonics for ultra high efficiency visible leds |
| url | http://hdl.handle.net/1721.1/116357 https://orcid.org/0000-0003-0420-2235 |
| work_keys_str_mv | AT ramrajeevj thermophotonicsforultrahighefficiencyvisibleleds |