Tuning the Work Function and Properties of the Conducting Polymer PEDOT:PSS for Enhancing Optoelectronic Device Performance of Solar Cells and Organic Light Emitting Diodes

Easy-to-fabricate, flexible optoelectronic devices based on conducting organic polymers are in high demand due to their cost-effectiveness and low weight. The hole and electron transport layers (HTL/ELT) are central to the working of these devices. Conductive polymers are now extensively used (HTL/ETL) in solar cells, as hole injection layers in OLEDs, and as electrodes or active channel layers in organic thin film transistors. Poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) is the mainstay of these devices. The energy levels of the tailored PEDOT:PSS determine the work function, the efficiency of charge separation, and the device's performance. Transparent electrodes are another requirement for the efficient functioning of devices, with indium tin oxide (ITO) being a common choice. To overcome problems associated with ITO, researchers are focusing on conducting polymer materials such as PEDOT:PSS as transparent electrode materials. Flexibility, water processability, high electrical conductivity, good optical transparency, biocompatibility, and good thermoelectric properties make functionalized PEDOT:PSS a versatile conductive polymer. Priced for its versatility and good performance, it is used in cutting-edge applications including LEDs, solar cells, and sensors. Cost-effective production and easy production scalability make it a default material for optoelectronic applications despite some challenges. This review highlights recent research with special emphasis on tuning the work function of PEDOT:PSS to enhance the performance of optoelectronic devices.