Nanopartículas de Nb2O5 aplicadas a células solares de perovskita

• Ano de defesa: 2024
• Autor(a) principal: Assunção, João Pedro Ferreira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Estadual Paulista (Unesp)
• Palavras-chave em Português: Células solares de perovskita; Camada compacta; Camada mesoporosa; Péntóxido de nióbio
• Link de acesso: https://hdl.handle.net/11449/253408

Currently, one of the most promising technologies in the field of photovoltaic devices are the so-called perovskite solar cells (CSPs). Its rapid advancement (today presenting more than 26% conversion efficiency) associated with its low production cost, make this technology highly attractive to the industrial sector. Despite their great progress, CSPs still face challenges that slow down their commercialization, the main ones being their scaling and long-term stability. Therefore, the present work proposes an alternative route for the production of Nb2O5 nanoparticles (NPs) and their application as an electron transport layer in CSPs, aiming to advance the issues surrounding the challenges of their commercialization. The results obtained show that self-suspended and crystalline Nb2O5 nanoparticles with dimensions of 20 nm were synthesized in times shorter than 15 minutes by the microwave-assisted hydrothermal method. The developed nanoparticles were applied as an electron transport layer in perovskite solar cells. The results obtained show that its application as compact films resulted in devices with a maximum efficiency (PCE) of 18.4%. For devices with mesoporous Nb2O5 films, the best devices presented a maximum PCE of 18.2%. The Nb2O5-based devices were compared with standard devices based on the compact Nb2O5 sol-gel layer and mesoporous TiO2, showing a maximum PCE of 18.1%. In general, the results indicate that solar cells prepared with compact Nb2O5 NP films with a concentration of 100 mg.mL-1 present optoelectronic and transport parameters similar to control cells, demonstrating that the route proposed in this work can be used in the production of High-efficiency CSPs compatible with devices demonstrated in the literature. The results also demonstrate that the application of two-bed Nb2O5 mesoporous films also produces parameters similar to those found in standard devices. On the other hand, the deposition of only one layer resulted in uncovered areas and devices that present high hysteresis. Furthermore, the capacitances in 1-layer devices are larger, suggesting that the observed hysteresis is promoted by charge accumulation in the uncovered areas.