  Herein we present a comparative study among different mesoporous electron
transporter layers (ETLs), namely nanometric m-TiO2, m-SnO2 and m-SnO2 quantum
dots (QDs), deposited by spray coating method. The experimental data correlated
with the photovoltaic parameters indicate that the SnO2 mesoporous layer
obtained from the spray deposition of the in-house prepared QDs solution is the
best candidate between the three used mesoporous ETLs. The use of the in-house
prepared SnO2 QDs solution presents smaller agglomerates composed of 3 nm NPs
resulting in the formation of a thinner, more uniform, and compact mesoporous
ETL, compared with the other two ETL solutions. The
formamidinium-methylamonium-potassium (FAMA@10K) perovskite deposited on this
m-SnO2 QDs ETL presents a lower RMS, more uniformity and, a higher amount of
PbI2. Interestingly, this higher concentration for PbI2 seems to enhance the
performance of the perovskite solar cells (PSC), compared to the other two
mesoporous ETLs. Our work reveals that SnO2 QDs solution can be easily produced
in the laboratory and it is more suited for the deposition of the mesoporous
ETL when choosing a FAMA@10K configuration perovskite solar cell with power
conversion efficiency (PCE) higher than 10%.
