Fully High‐Temperature‐Processed SnO₂ as Blocking Layer and Scaffold for Efficient, Stable, and Hysteresis‐Free Mesoporous Perovskite Solar Cells

Abstract

Planar perovskite solar cells (PSCs) based on low-temperature-processed (LTP) SnO 2 have demonstrated excellent photovoltaic properties duo to the high electron mobility, wide bandgap, and suitable band energy alignment of LTP SnO 2 . However, planar PSCs or mesoporous (mp) PSCs based on hightemperature-processed (HTP) SnO 2 show much degraded performance. Here, a new strategy with fully HTP Mg-doped quantum dot SnO 2 as blocking layer (bl) and a quite thin SnO 2 nanoparticle as mp layer are developed. The performances of both planar and mp PSCs has been greatly improved. The use of Mg-SnO 2 in planar PSCs yields a high-stabilized power conversion efficiency (PCE) of close to 17%. The champion of mp cells exhibits hysteresis free and stable performance with a high-stabilized PCE of 19.12%. The inclusion of thin mp SnO 2 in PSCs not only plays a role of an energy bridge, facilitating electrons transfer from perovskite to SnO 2 bl, but also enhances the contact area of SnO 2 with perovskite absorber. Impedance analysis suggests that the thin mp layer is an "active scaffold" selectively collecting electrons from perovskite and can eliminate hysteresis and effectively suppress recombination. This is an inspiring advance toward high-performance PSCs with HTP mp SnO 2 .

3 D NiO Nanowall Hole‐Transporting Layer for the Passivation of Interfacial Contact in Inverted Perovskite Solar Cells

“…The thickness of the NiO NWs‐6h film was approximately 200 nm. Such a high‐quality mesoporous film could provide a large surface area for the deposition and filling of a perovskite layer . A comparison of a perovskite film deposited on a NiO NWs layer with different hydrothermal growth times is shown in Figure b–d.…”

“…Herein, we report a hydrothermal synthesis of a 3 D mesoporous NiO nanowall (NW) HSCs as an interface engineering strategy for the preparation of efficient inverted PSCs. The hydrothermal method is an effective approach for the development of high‐quality metal oxide films featuring excellent uniformity, continuity, and crystallinity . Therefore, improved interface contact features with low defect density and enhanced quality of the perovskite layer could be effectively achieved for such 3 D NiO NWs mesoporous films.…”

“…The hydrothermalm ethod is an effective approach for the development of high-quality metal oxide films featuring excellent uniformity, continuity,a nd crystallinity. [24,34] Therefore, improved interface contact features with low defect density and enhanced quality of the perovskite layer could be effectively achieved for such 3D NiO NWs mesoporous films. This contributes to better charge transport/extractionw ith lower interfacial energy loss.…”

Review of Novel Passivation Techniques for Efficient and Stable Perovskite Solar Cells

“…Passivation of carrier transport layers has been effective in overcoming UV instability and hysteresis issues although there remain opportunities for improving thermal stability. Especially, the use of organic hole transport materials such as the commonly used Spiro‐OMeTAD is a bottleneck due to its low thermal durability and complications with the use of LiTFSI and TBP dopants.…”

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

“…As the most applied material for the electron transfer layer, TiO 2 has shown unavoidable shortcomings of high‐temperature annealing and low electron mobility. SnO 2 and ZnO have been investigated as alternatives to TiO 2 in flexible PSC devices. SnO 2 has also been widely used as an electron transfer material because the crystallization temperature of SnO 2 is lower than that of TiO 2 .…”