We reported the comparative studies of the optimization of solution-processable tungsten trioxide (WO₃) as a hole transporting layer (HTL) in inverted organic photovoltaics (OPVs) using spin coating, slot-die coating, and spray coating technologies for scaling-up applications. To facilitate the technology’s transition into commercial manufacturing, it is necessary to explore the role of scalable technologies for low-cost and efficient device fabrication. We investigated the role of diluting WO₃ with isopropanol as an HTL in inverted OPVs to solve the issue of poor wettability of the hydrophobic surface of the PBDB-T: ITIC bulk heterojunction layer. The optimal dilution ratios of WO₃ with isopropanol were 1:4, 1:4 and 1:8 with spin coating, slot-die coating and spray coating techniques, respectively. We evaluated the device performance by conducting a current density–voltage (J-V) analysis, incident photon-to-current conversion efficiency (IPCE) measurements, and ultraviolet–visible (UV-Vis) absorbance spectra for various WO₃ concentrations. The J-V characteristics revealed that slot-die coating resulted in the highest performance, followed by the spray coating technology. We further investigated the impact of the annealing temperature on device performance for both slot-die- and spray-coated diluted WO₃. The highest device performance was achieved at an annealing temperature of 120 °C for both coating technologies. This research offers valuable insights into the scalable fabrication of inverted OPV devices, paving the way for cost-effective and efficient large-scale production.

Hybrid metal halide perovskites, specifically methylammonium lead bromide (MAPbBr3), have promising optoelectronic properties and cost-effective fabrication methods; however, challenges in achieving high photoluminescence quantum yield persist. This study explores morphology engineering of MAPbBr3 films to enhance their applicability in light-emitting diodes by sequential spin-coating methods with toluene and chloroform antisolvents, incorporating bathocuproine (BCP) as an additive. BCP is shown to improve film morphology, reducing grain size and surface roughness while increasing coverage, uniformity, and the conductivity of the layer. A novel double-layer deposition approach further enhances these properties, yielding films with complete coverage and minimized defects, without change in the microstrain. Photoluminescence measurements indicate significant trap passivation and enhanced light emission intensity and stability and a reduced threshold in the generation of amplified spontaneous emission. When integrated into PeLED devices, these engineered films demonstrate substantial performance improvements. The combination of BCP and double-layer deposition results in a luminous efficiency increase of up to 727 times compared to untreated films. This enhancement is attributed to better charge transport, reduced non-radiative recombination, and superior film morphology. This work presents a scalable and efficient method for producing high-performance MAPbBr3 films, bridging the gap between simple fabrication processes and advanced device applications.

The effect of doublet state metalloradical complex in a solar cell inside the common active layer poly(3-hexylthiophene)/[6,6]-phenyl-C61-butyric acid methyl ester (P3HT/PC₆₀BM) is explored. In this work, it is demonstrated that the role of the bis-[1,3-bis-(2,6-diisopropylphenyl)-4,5-dichloroimidazol-2-ylidene]palladium(I) hexafluoridophosphate dopant, [Pd(IPr^Cl)₂][PF₆], is crucial because the presence of a stable unpaired electron in the molecule significantly improves the optoelectronic performance of the device. We f the optimal concentration of this molecule in the active layer and demonstrate that the presence of this additive in the active layer helps to significantly improve the morphology of the device. The improvements in optoelectronic and morphological parameters are associated with a remarkable increase in photocurrent generation due to more favorable mechanisms of charge separation at the donor/acceptor (D/A) interfaces of the active layer and reduced recombinations. Moreover, the presence of this additive improves the stability of the unencapsulated solar cell against photochemical degradation produced by sunlight.

The effect of doublet state metalloradical complex in a solar cell inside the common active layer poly(3-hexylthiophene)/ [6,6]-phenyl-C61-butyric acid methyl ester (P3HT/PC60BM) is explored. In this work is demonstrated that the role of the Bis-[1,3-Bis-(2,6-diisopropylphenyl)-4,5-dichloroimidazol-2-ylidene]palladium(I) hexafluoridophosphate dopant, [Pd(IPrCl)2][PF6], is crucial because, by having a stable unpaired electron in the molecule, it significantly improves the optoelectronic performance of the devices. We found the optimal concentration of this molecule in the active layer, and we demonstrated that the presence of this additive in the active layer helps to significantly improve the morphology of the device. The improvements in optoelectronic and morphological parameters are associated with a remarkable increase of photocurrent generation due to more favourable mechanisms of charge separation at the donor/acceptor (D/A) interfaces of the active layer and reduced recombinations. Moreover, the presence of this additive improves the stability of the unencapsulated solar cell against photochemical degradation produced by sunlight.