Influence of Surface Polarity on Optoelectronic Properties of PEDOT:PSS/ZnO Hybrid Heterojunctions

Abstract

The influence of polar and nonpolar crystallographic orientations of ZnO substrates on the current transport mechanism in poly(3,4‐ethylenedioxythiophene) poly(4‐styrenesulfonate) (PEDOT:PSS)/ZnO heterojunctions is investigated by DC and AC electrical measurements. It is shown that PEDOT:PSS forms high‐quality rectifying junctions on nonpolar planes of n‐type ZnO substrates, whereas on polar c‐planes, the quality of the junction is affected by the surface polarity, with lower‐quality junctions formed on the O‐polar c‐plane. The lower quality of the junction is attributed to partial degradation of the O‐polar surface caused by the acidic nature of PEDOT:PSS. By the analysis of current–voltage characteristics, it is demonstrated that the recombination‐tunneling mechanism dominates charge transport in the forward direction. An equivalent circuit is proposed to interpret the data obtained by impedance spectroscopy and the parameters of the equivalent circuit are extracted.

Organic Heterostructures with Indium‐Free Transparent Conductor Electrode for Optoelectronic Applications

“…Besides the advantages, the PEDOT‐PSS layer smoothens the surface of triple layer and avoids shorts and protects the active layer from oxygen, increasing the device lifetime, it also shows disadvantages such as a strongly acid character with the potential to cause the degradation of the electrode and/or mixed layer. The acidic nature of PEDOT‐PSS can generate the degradation of the ZnO surface [ 30 ] with effect on charge carrier injection/collection. The thickness of PEDOT‐PSS also strongly affects the properties of the organic heterostructures with mixed layer, directly by modification on the properties of PEDOT‐PSS, such as roughness, or indirectly by the influence of the PEDOT‐PSS surface properties on the properties (roughness, thickness) of the mixed layer deposited by MAPLE on top.…”

“…[26] Thus, much attention was paid to investigate the influence of the preparation conditions on the properties of the multilayer TCE in correlation with different types of devices. [27,28] A conductive polymer, like poly (3,4ethylenedioxythiophene): poly(styrenesulfonate)/PEDOT-PSS, a p-type semiconductor with a high work function (5.2 eV), a wide transparency domain, and very good mechanical flexibility, which can be processed at low temperature by cheap solution methods, is one of the most promising candidates as a buffer layer mostly used for holes' injection, [29,30] from ITO to the organic active layer.…”

Investigation of fundamental electrical and optoelectronic properties of an organic- and carbon-based MnPc/GC photodiode with high photosensitivity

“…These interfaces have, however, attracted significant attention in the field of optoelectronics due to their potential to enhance the performance of electronic devices such as solar cells, photodetectors, and light-emitting diodes [2][3][4]. Hybrid heterojunctions can offer a number of benefits over traditional devices, including improved stability, enhanced optoelectronic properties, and increased charge separation and transport [5,6].…”

Orientation-Mediated Luminescence Enhancement and Spin-Orbit Coupling in ZnO Single Crystals

“…The intense near band edge emission and the large exciton binding energy make ZnO a promising candidate for optoelectronic devices such as laser diodes [8], light-emitting diodes [9], and photodetectors [10]. Moreover, the availability of polar and non-polar faces in zinc oxide single crystal adds variety in tuning its optical and electronic properties; for example, radiation absorption and emission from ultraviolet (UV) to near-infrared (NIR) region [11,12]. To achieve the best output from ZnO-based devices, it is important to select a suitable growth direction (polar and non-polar faces) depending upon own needs.…”