Introduction of carbon nanodots into SnO₂ electron transport layer for efficient and UV stable planar perovskite solar cells

Abstract

The high-performance of planar perovskite solar cells with SnO2:CNDs.

Chlorine‐modified SnO2 electron transport layer for high‐efficiency perovskite solar cells

“…It has attracted tremendous research efforts for its high transmittance, suitable bandgap, matched energy level, high electron mobility, and low temperature preparation. Significant efforts have been devoted to developing highly efficient PSCs by utilizing a SnO 2 ETL . Thus far, the certified efficiency of cells with a SnO 2 ETL has reached 23.3%, the highest efficiency for the planar‐type PSCs reported to date; however, based on the Shockley‐Queisser theory, the theoretical PCE limit is 30.5%.…”

“…Significant efforts have been devoted to developing highly efficient PSCs by utilizing a SnO 2 ETL. [28][29][30][31][32][33][34][35][36] Thus far, the certified efficiency of cells with a SnO 2 ETL has reached 23.3%, the highest efficiency for the planar-type PSCs reported to date 37 ; however, based on the Shockley-Queisser theory, the theoretical PCE limit is 30.5%. The main reason for PCE loss is carrier recombination.…”

Improving the Stability of Ambient Processed, SnO2‐Based, Perovskite Solar Cells by the UV‐Treatment of Sub‐Cells

“…[49] Figure 3d shows the energy-level diagram where a higher conduction band level of SnO 2 (-3.67 eV) was observed when compared with the values (À3.9 to À4.5 eV) shown most times in literature. [17,19,25,32] This causes a mismatch at the SnO 2 / perovskite interface. It could have been caused by the slot-die coating of SnO 2 and requires further investigation beyond the current scope of this work.…”

“…The stability of SnO 2 -containing devices has been studied under varied test conditions, such as dark storage, [16][17][18] 1 sun illumination, [19,20] and under UV exposure, [19,21,22] however, conflicting conclusions have been drawn on the role of SnO 2 in perovskite degradation. This is partly due to the lack of standardized testing protocols and also because of the large differences in material and fabrication procedures.…”

“…In contrast to the dark storage test, a steady decline in PCE is reported when devices are subjected to constant 1 sun illumination, and the performance is monitored by intermittent J-V measurements or maximum power point (MPP) tracking. [17,19,20] In other studies, UV tests are conducted and have shown varying results depending on the UV wavelength. For example, glass/ ITO/SnO 2 /MAPbI 3 /Spiro-OMeTAD/Au devices showed negligible PCE degradation with UV-B (370 nm) irradiation over 1750 h, however, significant degradation occurred with UV-A (311 nm) exposure due to the degradation of the perovskite.…”