Production of perovskite solar cells by solution and vacuum based methods and their characterization

In this thesis study, perovskite solar cells production was tried to be optimized using solution and vacuum based deposition methods. In solution deposition, two different perovskite compounds were used, i.e., MAPbI3 and Cs(0,05)FA(0,85)MA(0,1)PbI(2,7)Br(0,3). The cells with FTO/c-TiO2/m-TiO2/perovskite/Spiro-OMeTAD/Au configuration were fabricated via Cs(0,05)FA(0,85)MA(0,1)PbI(2,7)Br(0,3) composition as the absorbing layer and exhibited Voc of 1.105 V, Jsc of 23.38 mA/cm2, FF of 0.66, and PCE of 17.0%. In addition, planar cells were produced with SnO2 as a substitute for c-TiO2/m-TiO2 electron transporting layer. These cells displayed an efficiency of 15.06% with the corresponding photovoltaic parameters; Voc 1.091 V, Jsc 22.63 mA/cm2, and FF 0.54. Moreover, perovskite solar cells were fabricated with inorganic CuSbS2 hole transporting layer, however the efficiency of the cell was only 4.3%. This low efficiency was attributed to poor packing of the plate-like CuSbS2 particles on the perovskite layer with the formation of a noncontinous layer. In vacuum deposition method, MAPbI3 based perovskite solar cells with various hole transporting layers such as MoO3/TaTm, MoO3/H2, MoO3/PTAA, PTAA, and PolyTPD were fabricated by employing the C60/BCP as electron transporting layer. Among them, the cell produced with PTAA showed the highest stability under thermal stresses. This cell exhibited an efficiency of 19.2% with Voc of 1.087 V, Jsc of 22.12 mA/cm2, and FF of 0.79. The cell retained 92% and 82% of its initial PCE after aging for 850 h at room temperature and 65 °C, respectively. Even after thermal cycling between room temperature and 85 °C for 200 cycles, 95% of the initial PCE was maintained. Under continuous illumination and with maximum power point tracking (MPPT) Ts80 life time was obtained as 230 h. The decay of the initial efficiency under illumination was determined to be related with the decrease in the crystallinity of the perovskite layer. This also led to a decrease in the optical absorption of the cell. Moreover, Shockley-Read-Hall recombination rate was increased due to the increase in the concentration of defects or trap states in the crystal structure. Therefore, the study has clearly shown that the decrease in the efficiency of the cells under operating conditions was originated from the perovskite layer.