Oxygen Vacancy Management for High‐Temperature Mesoporous SnO₂ Electron Transport Layers in Printable Perovskite Solar Cells

Abstract

The planar SnO 2 electron transport layer (ETL) has contributed to the reported power conversion efficiency (PCE) record of perovskite solar cells (PSCs), while the high-temperature mesoporous SnO 2 ETL (mp-SnO 2 ) brings poor device performance. Herein, we report the application of mp-SnO 2 for efficient printable PSCs via oxygen vacancy (OV) management by introducing magnesium (Mg) into the paste. We find that high-temperature annealing suppresses self-doping of SnO 2 by reducing OVs. The introduced Mg occupies both the Sn site and interstitial site of SnO 2 and promotes the formation of OVs. Lattice Mg tends to induce neutral OVs and interstitial Mg could promote the ionization of neutral OVs for self-doping. The synergy effect on OVs increases the carrier density and upshifts the Fermi level energy of mp-SnO 2 , ensuring its capability as the well-performed ETL with trap-less charge transport and suppressed surface recombination for dramatic improved device PCE from 6.62 % to 17.25 %.

Enhancing the Performance of Fa‐Based Printable Mesoscopic Perovskite Solar Cells via the Polymer Additive

“…The first semi‐circle at the high frequency represents the charge transfer at the interface, and the second circle at the low frequency represents the charge recombination in the device (Figure 3d). [ 39 ] In the high‐frequency region, there is not much difference, consistent with the discussion that the mesoscopic structure benefited effective charge transfer. In the low‐frequency region, the device with PAN had an enlarged semicircle radius, which indicated suppressed recombination due to defect passivation and improved crystallinity.…”

Stabilizing Oxidation State of SnO2 for Highly Selective CO2 Electroreduction to Formate at Large Current Densities

“…In O 1s X-ray photoelectron spectroscopy (XPS), the peak area of O v in Cu–SnO 2 increases notably compared with pure SnO 2 (Figure S7a). Simultaneously, the Sn 3d 3/2 and Sn 3d 5/2 peaks of Cu–SnO 2 slightly shift to low binding energy to maintain electrical neutrality and compensate for the influence of O v (Figure S7b). These results imply that, compared with Bi and Pt, low-valence Cu single atoms can introduce more O v into the SnO 2 lattice.…”

“…Simultaneously, the Sn 3d 3/2 and Sn 3d 5/2 peaks slightly shift negatively to compensate for the influence of O v . Additionally, the Cu 2p spectra of 0.6Cu–SnO 2 , 2Cu–SnO 2 , and 13Cu–SnO 2 exhibit the same Cu 2+ patterns. ,, In brief, the results above demonstrate that 0.6Cu–SnO 2 , 2Cu–SnO 2 , and 13Cu–SnO 2 are three representative samples that exhibit different amounts of O v in SnO 2 structures.…”

Depth‐Dependent Post‐Treatment for Reducing Voltage Loss in Printable Mesoscopic Perovskite Solar Cells

“…The main methods of improving the performance of mesoscopic PSCs include tuning the perovskite crystallization, adjusting the composition of perovskite, [8][9][10][11][12] modifying the interfaces and developing the charge selective materials and electrode materials. [13][14][15][16][17] Through these efforts, the highest certified PCE for the printable mesoscopic PSCs has now reached 17.7% [12] and the highest reported PCE is 18.8%. [10] At present, the crystallization process of perovskite in mesoscopic scaffolds is controllable, and the morphology and crystallinity have been significantly improved.…”