Jennifer Estrada, Camilo Otalora and Gerardo Gordillo
Universidad Nacional de Colombia, Colombia
Posters & Accepted Abstracts: J Phys Chem Biophys
Hybrid organic/inorganic perovskite materials (e.g., CH3NH3PbI3) as light absorbers are currently among the most promising candidates for thin-film photovoltaic (PV) applications. Great advances in terms of efficiency have been achieved with this type of devices, however there are many doubts about their properties and the relationship of these with the efficiency of the devices. In this work, thin films of MAPbI3, MAPbI2Br and MAPbI2Cl were evaluated through photoconductivity measurements, which allowed to determine the activation energy corresponding to the levels associated to the trap centers present in the samples studied. Through fitting of decay curves of photocurrent simulated theoretically to the one obtained experimentally, it was possible to determine the values of the time constants (ti) corresponding to each kind of trap centers. The activation energy associated to these traps was estimated from an Arhenius type fitting of the ti values obtained at different temperatures in the range between room temperature and 100ºC. It was found evidence for the presence of three types of traps in the studied perovskite films (MAPbI2Cl, MAPbI2Br and MAPbI3), which differ both in depth and in the values of the corresponding time constants.
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