In recent years, several strategies have been proposed and demonstrated to enhance the efficiency of organic light-emitting diodes (OLEDs) and organic photovoltaics (OPVs). In both types of devices, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) is commonly used to enhance hole injection. The layer is further designed by incorporating metallic-based, carbon-based, organic, inorganic, and hybrid nanoparticles with the aim of improving the performance and hence the efficiency through the improvement of light out-coupling in OLEDs and enhancement in light absorption generation of hole-charge carriers in OPVs. This review elucidates the use of different types of nanoparticles that are doped into PEDOT:PSS and their effects on OLEDs or OPVs. The effects include surface plasmon resonance (SPR), scattering, better charge transport, improvement in surface morphology and electrical properties of PEDOT:PSS. Promising results have been obtained and can potentially lead to low cost, large-area manufacturing process.

In this work, polymers of poly[(9,9-dioctylfluorenyl-2,7-diyl)-co-triphenylamine] with side chains containing: pyrene (C1), diphenyl (C2), naphthalene (C3), and isopropyl (C6) structures were synthesized via a Suzuki coupling reaction. The structures were verified using NMR and cyclic voltammetry measurements provide the HOMO and LUMO of the polymers. The polymer with pyrene (C1) and naphthalene (C3) produced photoluminescence in the green while the polymer with the side chain containing diphenyl (C2) and isopropyl (C6) produce dual emission peaks of blue-green photoluminescence (PL). In order to examine the electroluminescence properties of the polymers, the solutions were spin-coated onto patterned ITO anode, dried, and subsequently coated with an Al cathode layer to form pristine single layer polymer LEDs. The results are compared to a standard PFO sample. The electroluminescence spectra resemble the PL spectra for C1 and C3. The devices of C2, C3, and C6 exhibit voltage-dependent EL. An additional red emission peak was detected for C2 and C6, resulting in spectra with peaks at 435 nm, 490 nm, and 625 nm. The effects of the side chains on the spectral characteristics of the polymer are discussed.

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Nanodiamonds (NDs) have attracted great interest due to their high refractive index and thermal conductivity. The unique properties of NDs, including high thermal conductivity, chemical stability, and tensile strength, make them a promising candidate for enhancing OLED efficiency. NDs were coated either beneath or above the PEDOT:PSS hole injection layer in a green-emitting OLEDs (ITO/ PEDOT:PSS/NPD/CBP:Ir(ppy)3/TPBi/Liq/Al). The best performance is obtained from the device with NDs layer beneath the PEDOT:PSS layer where the current efficiency (CE) is increased by 5.4%, power efficiency (PE) is increased by 17.7% and the external quantum efficiency (EQE) is increased by 4.5% at a luminance of 10000 cd/m2 as compared to a standard device without NDs layer.

Single layer organic light emitting diode (OLED)devices based on poly{[2-methoxy-5-(-2ethylhexyloxy)-1,4-phenylene]vinylene}(MEH-PPV)are fabricated and studied in this work .There are several factors that affect the performance of the fabricated OLED samples. Some of these factors are related to the fabrication parameters chosen for the OLED fabrication process. The effect of concentration and annealing temperature are investigated. Other environmental factors such as humidity or temperature affect the performance of fabricated OLED samples under long term exposure. An internet of things environment monitoring system (IoT-EMS) is developed to monitor and study the effect of these factors on the performance of the OLED samples. Exposure to humidity is found to severely degrade the samples. In summary, the optimum concentration for MEH-PPV is concluded to be4 mg/ml, and the best annealing temperature is 90C in this study. It is also deduced that humidity of 72-75% caused degradation of the samples in less than 20 hours.