Use of an OLED as a thermal source to supply integrated organic Peltier unit

In this work, we have investigated the integration of an organic Peltier unit into an organic light-emitting diode (OLED). The corresponding complete device has been realized by using the same organic materials for OLED and by designing a special architecture where the cathode is shared by the Peltier and the OLED units. Consequently, the experimental process did not require more time and materials than the realization of a single OLED device. The structures used for the Peltier and OLED units are respectively ITO/TPD/Al/Alq3/ITO and ITO/TPD/Alq3/Al. Experimentally, the OLED has a threshold voltage around 22 V with a current about 0.1 mA and for a 2–4 mm2 active area. Using an infrared camera, the increase in temperature of the OLED was determined to be about 0.45 °C and a Peltier voltage of 0.88 mV was recorded with a 25 V OLED supply voltage. This result shows that it is possible to convert thermal source provided by an OLED into electricity introducing the new concept of organic Peltier and light-emitting diode device.