Unraveling the effect of mixed charge carrier on the electrical conductivity in MAPbBr 3 perovskite due to ions incorporation

We have investigated the role of H + , Bi 3+ , and Sb 3+ ions incorporation on the structural, morphological, optical, and transport properties in MAPbBr 3 perovskite. A comprehensive study of the Bi/Sb- and H + -doped samples on electrical transport properties as a function of light, and within the solar cell working temperature window reveals a hidden effect on the charge transport. Interestingly, Bi-doped samples produced at different acid concentrations showed an anomalous photoconductivity effect at room temperature accompanied by a suppression of photoluminescence emission peak suggesting the creation of non-radiative energy levels. Our results put forward that the coexistence of Bi 3+ and interstitial protons in the doped samples collaborate to the detriment of electrical conductivity causing a large hysteresis during the thermal cycles, differently from the observed for the Sb-doped counterpart. Therefore, we pointed out that the presence of H + ions in high concentration during the synthetic procedure associated with bismuth ions brings about harmful hysteresis and anomalous photoconductivity effects close to the solar cell working temperature which in turn causes degradation and low stability of the devices.