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| Author(s): |
Silvia Leticia Fernandes
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | Bauru. 2016-06-01. |
| Institution: | Universidade Estadual Paulista (Unesp). Faculdade de Ciências. Bauru |
| Defense date: | 2016-04-27 |
| Advisor: | Maria Aparecida Zaghete Bertochi; Carlos Frederico de Oliveira Graeff |
| Abstract | |
The development of perovskite solar cells was accompanied by a revolution in the photovoltaics field. Perovskite solar cells have reached higher energy conversion efficiencies of 21% in just 5 years after its discovery, putting them in competition with commercial silicon solar cells. Although promising, the perovskite devices face some challenges which delay their commercialization, and one of most important is the stability. In this context, the present thesis intended the development of perovskite solar cells based on nanostructured films of Nb2O5 and TiO2, in order to better understand the functioning of these devices. Efficiencies up to 13% were obtained for the system composed of: compact Nb2O5 / mesoporous TiO2/ CH3NH3PbI3 and efficiencies as high as 15% for compact system using compact TiO2/ mesoporous TiO2/ CH3NH3PbI3. The best solar cells prepared using compact Nb2O5 films showed a short circuit current of 19 mA/cm 2 , open circuit voltage of 900 mV, fill factor of 75% and 13% of efficiency. Devices prepared using compact TiO2 films reached short circuit current of 20 mA/cm2 , open circuit voltage of 1V, fill factor of 70% and 15% of efficiency. The stability of the devices and the presence of current-voltage hysteresis were studied by changing parameters such as the composition and the thickness of the compact layer (TiO2 vs. Nb2O5), as well as the synthesis method used to prepare the perovskite films (sequential deposition method vs solvent-engineering method). Overall, the results showed that solar cells prepared with 50 nm Nb2O5 film in combination with perovskite prepared by sequential deposition method have resulted in devices without hysteresis and greater stability than those prepared with TiO2 films or thicker than 50nm. (AU) | |
| FAPESP's process: | 12/07745-9 - Development of hybrid solar cells based on ZnO and Nb2O5 nanostructured films |
| Grantee: | Silvia Leticia Fernandes |
| Support Opportunities: | Scholarships in Brazil - Doctorate |