Effect of the concentration of TEA on the formation of lead hydroxide micro to nanoparticle

The Effect of Impurities on the Impedance Spectroscopy Response of CH3NH3PbI3 Perovskite Solar Cells

“…The PbI 2 layer was treated with MA in a chamber in ambient air and converted to a film containing a mixture of perovskite (XRD in Figure a) with a large quantity (33 mol %) of Pb compounds . Pb can form dozens of oxide/hydroxide compounds with different stoichiometry, , thus for the sake of simplicity the Pb compounds in our samples will be mentioned hereafter in the text as Pb x (O/OH) y . The absence of additional peaks in the XRD result for sample “MA cell” (Figure a) suggests that Pb x (O/OH) y mainly exists in the amorphous state.…”

“…In the literature, band gap energies in the range 1.35 to 4 eV can be found for Pb x O y and 3.28 to 4.51 eV for Pb x (OH) y . 24,25 The larger band gap corresponds to lower oxidation state (Pb 2+ ), which is the most stable state of Pb. Our fabrication processes are carried out at low temperatures, thus we believe the asformed Pb x (O/OH) y will exist in the form of low Pb oxidation states, coinciding with the large band gaps.…”