Synthesis of Inorganic Halide Perovskite Quantum Dots for Photoluminescence Applications

• Autor(a) principal: Magalhães, Débora Vale
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/56425
• topic: inorganic perovskite; quantum dots; nanocrystals; photoluminescence; optical properties; stability; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia dos Materiais

Metal halide perovskite crystal structures have emerged as an attractive class of optoelectronic materials due to their excellent optical absorption and emission properties. Restricting the physi-cal dimension of the crystallite to the nanometer scale revealed quantum-confinement effects sim-ilar to those presented by traditional chalcogenide quantum dots. The synthetized inorganic per-ovskite quantum dots (IPQD) were characterized by spectroscopic measurements (absorption and photoluminescence emission spectra). Two synthesis methods were studied (supersaturation re-crystallization (SR) and hot-injection method (HI)) and the latter was chosen to be employed for the remaining work stages, due to observed better properties. The final goal was to obtain IPQDs doped with metals, focusing in Cd2+. The obtained samples of bromide-based perovskite doped with CdI2 exhibit more defined emission peaks with smaller full width at medium height (FWHM) and the samples appear to show improved stability when compared with blank CsPbBr3. The smaller FWHM was also observed for the CsPbI3 doped with CdI2. Inductively coupled plasma atomic emission spectroscopy (ICP-AES) was performed for samples with 10 mol% and 30 mol% of CdI2, where it was verified that 2.6 % and 8.23 % of the doping was introduced in the final compound, respectively. Note that the latter value was significantly better than those reported in literature (about 2% of the initial amount). The observed optical properties and empirically im-proved stability make these nanocrystals promising materials in several optoelectronic applica-tions, namely LEDs, solar cells, lasers, among others.