Here, we discuss the use of metal oxide films as charge transport layers in polymer light-emitting diodes containing poly(9,9-dioctyl-9H-fluorene-2,7-diyl) (PFO) as emissive layer. A simple device architecture consisting of glass-ITO | poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) | poly(9-vinylcarbazole) (PVK) | PFO | Ca | Al was used as starting point. This device assembly allows the investigation of basic properties of polymeric emitting layers, but does not provide stable devices with high performances. Thus, a more complex, multilayered diode structure is needed. We pursuit that goal with focus on the use of low-cost, easily processed materials. At one side, solution-processed non-stoichiometric MoOx films were used to replace the PEDOT:PSS as hole transport layer. At the other interface, solution-processed ZnO films containing either the bare oxide or a ZnO/carbon dots composite were introduced as electron transport layer. By tunning the characteristics of the metal oxide films, the performance of the blue-emitting PFO-based polymer light-emitting diodes (PLEDs) was massively enhanced.

Hybrid organic-inorganic perovskites have attracted interest in photovoltaic applications due to their excellent optoelectronic properties and low-temperature processability. From 2009 to 2021, lab-scale perovskite solar cells (PSC) reached a power conversion efficiency (PCE) of 25.7%, and a PCE of 17.9% for perovskite solar modules with an area of 800 cm2. Here, we present an investigation using three deposition techniques, spin-coating, blade-coating, and spray-coating, to process the charge transport layers and the active layer of perovskite solar cells onto 5 cm × 5 cm sized substrates, with device structure glass/fluorine-doped tin oxide (FTO)/c-TiO2/meso-TiO2+Perovskite/2,2’,7,7’-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9’-spirobifluorene (spiro-OMeTAD) or poly(3-hexylthiophene) (P3HT)/Au. Large-area PSC achieved an open-circuit voltage of around 1.1 V and PCE of 6%. The power generated was sufficient to start a fan. Furthermore, the connection in series of two large-area PSCs generated a voltage of 1.9 V. Then, we developed a simple method for manufacturing a monolithic perovskite mini-module containing two series-connected PSCs without using laser-scribing processes (usually named P1, P2, and P3 processes). This mini-module delivered a voltage of 1.52 V. Both voltages (1.9 and 1.52 V) were enough to turn on a red (or yellow) light-emitting diode (LED). To our knowledge, this is the first scientific report describing the assembly of a large-area n-i-p perovskite single cell and mini-module in Brazil.