Effects of Layer Thickness and Annealing of PEDOT:PSS Layers in Organic Photodetectors

Journal article

We have investigated the effects of thickness variation and thermal treatment of the electrode polymer poly(3,4-ethylenedioxythiophene): poly(styrenesulfonic acid) (PEDOT:PSS) in photovoltaic and photodetector devices using conjugated polymer blends as the photoactive material. By variation of the PEDOT:PSS layer thickness between 25 and 150 nm, we found optimum device performance, in particular low dark current and high external quantum efficiency (EQE) and open-circuit voltage (Voc), at around 70 nm. This has been observed for two different active layers. Annealing studies on the PEDOT:PSS films, with temperatures varied between 120 and 400°C, showed an optimum device performance, in particular EQE and Voc at 250°C. This optimum performance was found to be associated with loss of water from the PSS shell of the PEDOT:PSS grains. For annealing temperatures above 260°C, device performance was dramatically reduced. This was associated with chemical decomposition leading to loss of sulfonic acid, although this did not significantly affect the in-plane conductivity. © 2009 American Chemical Society.

Authors: Friedel, B; Keivanidis, P; Brenner, T; Abrusci, A; McNeill, C

• Publication status: Published
• Journal: MACROMOLECULES
• Volume: 42
• Issue: 17
• Pages: 6741-6747
• Publication date: 2009-09-08
• DOI: 10.1021/ma901182u
• EISSN: 1520-5835
• ISSN: 0024-9297
• Language: English