Boosting the Efficiency of Perovskite Solar Cells with CsBr‐Modified Mesoporous TiO₂ Beads as Electron‐Selective Contact

Abstract

Rapid extraction of photogenerated charge carriers is essential to achieve high efficiencies with perovskite solar cells (PSCs). Here, a new mesoscopic architecture as electron‐selective contact for PSCs featuring 40 nm sized TiO2 beads endowed with mesopores of a few nanometer diameters is introduced. The bimodal pore distribution inherent to these films produces a very large contact area of 200 m2 g−1 whose access by the perovskite light absorber is facilitated by the interstitial voids between the particles. Modification of the TiO2 surface by CsBr further strengthens its interaction with the perovskite. As a result, photogenerated electrons are extracted rapidly producing a very high fill factor of close to 80% a VOC of 1.14 V and a PCE up to 21% with negligible hysteresis.

Activating Old Materials with New Architecture: Boosting Performance of Perovskite Solar Cells with H2O‐Assisted Hierarchical Electron Transporting Layers

“…[9,[31][32][33] Here, we suppose that the vertical architecture (with a large surface area) of the H-m-TiO 2 may form an additional radial collection path for photo-generated charges (Figure 6a,b), which may accelerate the extraction of photo-generated charges (Figure 6c,d). [9,[31][32][33] Here, we suppose that the vertical architecture (with a large surface area) of the H-m-TiO 2 may form an additional radial collection path for photo-generated charges (Figure 6a,b), which may accelerate the extraction of photo-generated charges (Figure 6c,d).…”

Formamidinium‐Based Lead Halide Perovskites: Structure, Properties, and Fabrication Methodologies

“…CsCO 3 treatment of the TiO 2 electron‐transport layer, combined with CsI doping of perovskite, has resulted in the high‐performance perovskite devices . Performance improvement has also been reported for CsBr‐modified TiO 2 …”

Nonsiliceous Mesoporous Materials: Design and Applications in Energy Conversion and Storage

“…Therefore, a reduction in the number of these traps can increase the PCE of a PSC. The interfacial defects can be repaired by using CsBr or TiCl 4 to occupy oxygen vacancies or by applying UV–ozone treatment to a mesoporous/compact TiO 2 layer to increase the conductivity and remove residual organics from the surface . The degradation of PSCs is mainly a result of surface recombination of TiO 2 with perovskite; this process can be prevented by using a mesoporous buffer layer of Al 2 O 3 …”