Efficient preparation of ultralarge graphene oxide using a PEDOT:PSS/GO composite layer as hole transport layer in polymer-based optoelectronic devices

Abstract

We herein report an investigation of ultralarge graphene oxide (UL-GO) sheet/poly(3,4ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) thin composite layers fabricated by spin coating on an indium-tin-oxide (ITO) anode as hole transport layer (HTL) in polymer light-emitting diodes (PLEDs), as well as polymer solar cells (PSCs). Monolayer UL-GOs were first synthesized based on a novel solution-phase method involving pre-exfoliation of graphite flakes which were then mixed into the PEDOT:PSS solution in various specific amounts. The PEDOT:PSS composite film mixed with 0.04 wt% UL-GO by weight exhibits a conductivity of 749.4 S cm À1 and a transmittance of 88.6% at 550 nm.The PEDOT:PSS/GO HTL shows enhanced charge carrier transport because of improved conductivity by the weakening of the coulombic attraction between PEDOT and PSS by the functional groups on GO nanosheets, and the formation of an extended conductive network. Moreover, it can effectively block electrons and reduce resistance in the HTL, leading to better injection and transport of holes and lower turn-on voltage and resulting in a higher overall efficiency in PLEDs. Similarly, it remarkably increases the short circuit current (J sc ), and PSC efficiency because of a remarkable reduction of exciton quenching that results in higher charge extraction in PSCs. The optimized PLEDs and PSCs with a PEDOT:PSS/GO composite HTL layer show a maximum luminosity of 725.6 cd m À2 (at 10.6 V) for PLEDs, as well as a power conversion efficiency of 3.388% for PSCs, which were improved by $11% and 12%, respectively, compared to reference PLEDs and PSCs with a PEDOT:PSS layer.

Influence of residual sodium ions on the structure and properties of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)

“…10,11 In these organic devices, PEDOT:PSS is commonly used as a hole-transporting layer (HTL) because it has relatively high hole mobility for the alignment of the work function of interfacial layers between the electrode and active layer. 12 Because this decrease in the energy barrier at the electrode contacts improves device performance, applications using PEDOT:PSS as a hole-transporting material have been developed.…”

Significantly improved photovoltaic performance in polymer bulk heterojunction solar cells with graphene oxide /PEDOT:PSS double decked hole transport layer

“…Therefore, recently combination of GO and PEDOT:PSS have been reported to effectively work as an HTL in OPVs. It is reported that use of a thin layer of GO underneath PEDOT:PSS can effectively prevent corrosion of ITO and its further diffusion into the photoactive layer23. Lee, Da-Young et al 24,.…”

Sensor for volatile organic compounds using an interdigitated gold electrode modified with a nanocomposite made from poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) and ultra-large graphene oxide

“…As shown in Fig. 6, the bright and dark domains are observed in phase images, corresponding to PEDOT-rich grains and PSS-rich grains, respectively [23,27]. The shape of PEDOT-rich grains transforms from a short curved domain to a long stretched network with increasing the amount of UL-GO to 0.04 wt% [27].…”

“…The sensitivity changing behaviors may be attributed to the adsorption and desorption of methanol molecules of the sensing films. This improvement may be resulted in the separation of PEDOT and PSS chains, mainly because the coulombic attraction between PEDOT and PSS was weakened by oxygenated functional groups on UL-GO sheets [23,27]. These covalently bond between PEDOT chains and UL-GO sheets made the conductive network.…”

“…Ultra-large graphene oxide (UL-GO) was synthesized based on the modified Hummers method using expanded graphite [23][24][25]. The obtained UL-GO particles were diluted using deionized water (~1 mg·mL −1 ) and mildly sonicated for 20 min in a bath sonicator, followed by mild-speed centrifugation at 5000 rpm for 5 min.…”