TY - JOUR
T1 - Impact of unintentional oxygen doping on organic photodetectors
AU - Euvrard, Julie
AU - Revaux, Amélie
AU - Cantarano, Alexandra
AU - Jacob, Stéphanie
AU - Kahn, Antoine
AU - Vuillaume, Dominique
N1 - Funding Information:
We thank Sylvie Lepilliet (IEMN-CNRS) for her help on the admittance spectroscopy set-up and measurements. A.K. acknowledges funding from the National Science Foundation under grants DMR-1506097 .
Publisher Copyright:
© 2017 Elsevier B.V.
PY - 2018/3
Y1 - 2018/3
N2 - Oxygen plasma is a widely used treatment to change the surface properties of organic layers. This treatment is particularly interesting to enable the deposition from solution of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) on top of the active layer of organic solar cells or photodetectors. However, oxygen is known to be detrimental to organic devices, as the active layer is very sensitive to oxygen and photo-oxidation. In this study, we aim to determine the impact of oxygen plasma surface treatment on the performance of organic photodetectors (OPD). We show a significant reduction of the sensitivity as well as a change in the shape of the external quantum efficiency (EQE) of the device. Using hole density and conductivity measurements, we demonstrate the p-doping of the active layer induced by oxygen plasma. Admittance spectroscopy shows the formation of trap states approximately 350 meV above the highest occupied molecular orbital of the active organic semiconductor layer. Numerical simulations are carried out to understand the impact of p-doping and traps on the electrical characteristics and performance of the OPDs.
AB - Oxygen plasma is a widely used treatment to change the surface properties of organic layers. This treatment is particularly interesting to enable the deposition from solution of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) on top of the active layer of organic solar cells or photodetectors. However, oxygen is known to be detrimental to organic devices, as the active layer is very sensitive to oxygen and photo-oxidation. In this study, we aim to determine the impact of oxygen plasma surface treatment on the performance of organic photodetectors (OPD). We show a significant reduction of the sensitivity as well as a change in the shape of the external quantum efficiency (EQE) of the device. Using hole density and conductivity measurements, we demonstrate the p-doping of the active layer induced by oxygen plasma. Admittance spectroscopy shows the formation of trap states approximately 350 meV above the highest occupied molecular orbital of the active organic semiconductor layer. Numerical simulations are carried out to understand the impact of p-doping and traps on the electrical characteristics and performance of the OPDs.
KW - Organic photodetectors
KW - Oxygen
KW - p-doping
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U2 - 10.1016/j.orgel.2017.12.008
DO - 10.1016/j.orgel.2017.12.008
M3 - Article
AN - SCOPUS:85038861268
SN - 1566-1199
VL - 54
SP - 64
EP - 71
JO - Organic Electronics: physics, materials, applications
JF - Organic Electronics: physics, materials, applications
ER -