Photovoltaic measurement of the built-in potential in organic light emitting diodes and photodiodes

Abstract

We measure the voltage at which the current under illumination in poly[2-methoxy, 5-(2-ethylhexoxy)-1,4-phenylene vinylene] based light emitting diodes is equal to the dark current. At low temperatures, this voltage, which we term the “compensation” voltage, is found to be equal to the built-in potential, as measured with electroabsorption on the same diode. Diffusion of thermally injected charges at room temperature, however, shifts the compensation voltage to lower values. A model explaining this behavior is developed and its implications for the operation of organic light emitting diodes and photovoltaic cells are briefly discussed.

Cathode dependence of the open-circuit voltage of polymer:fullerene bulk heterojunction solar cells

“…2͑b͒. 14 Furthermore, the accumulated charges at the interface will create a band bending, which leads to a reduction of the electric field in the bulk of the device. 15 The resulting voltage loss, indicated by ⌬V b in Fig. 2͑b͒, can be numerically calculated as a function of the barrier height b , using a model by Simmons.…”

Temperature-dependent built-in potential in organic semiconductor devices

“…This onset corresponds to V 0 as defined above, and is commonly referred to as the built-in voltage. 2,10,11 Comparison of Eq. ͑4͒ to experimental values of V 0 is not straightforward since Eq.…”

Asymptotic analysis of double-carrier, space-charge-limited transport in organic light-emitting diodes

“…where V is the applied potential (normalized by the thermal voltage, V =Vê/k BT ) minus the normalized built-in potential drop owing to the difference in the work functions of the anode and cathode [33]. The applied potential V is equal to the integral of the electric field E across where…”