Highly crystalline Nb-doped TiO₂ nanospindles as superior electron transporting materials for high-performance planar structured perovskite solar cells

Abstract

Highly crystalline Nb:TiO2 nanospindles have been successfully exploited as efficient ETMs in planar perovskite solar cells, achieving a power conversion efficiency of 20.8%, superior to that of the undoped one (19.1%).

A universal solution processed interfacial bilayer enabling ohmic contact in organic and hybrid optoelectronic devices

“…26 TiO 2 doped with Nb has been demonstrated to be an efficient ETL in perovskite and dye-sensitised photovoltaics, as well as in photocatalytic applications and battery electrodes, given its improvement in carrier density over pristine TiO 2 . [31][32][33][34][35][36][37][38][39][40][41] Light and dark field transmission electron microscopy (TEM) images of TiO 2 nanoparticles ( Fig. 1a and b, respectively) exhibit a lattice spacing of 0.29 nm between both {2 1 1} and {À2 1 À1} planes, with an average nanoparticle size of 7 nm.…”

Porous niobia spheres with large surface area: alcothermal synthesis and controlling of their composition and phase transition behaviour

“…4b(ii)), indicating that the composite MARIMOs consisted of solid solutions and the crystal lattice was enlarged by the doped Nb atoms with larger ionic radii (Nb 5+ ¼ 0.64 A, Ti 4+ ¼ 0.61 A). 37 Additionally, precursor solutions containing larger amounts of Nb(OEt) 5 resulted in the larger primary particle sizes of TiO 2 in the resulting MARIMOs (Table 1). However, this crystalline growth of TiO 2 was not observed for the Al 2 O 3 -TiO 2 , ZnO-TiO 2 , and SiO 2 -TiO 2 composites.…”

Enhanced fill factor for normal n‐i‐p planar heterojunction and mesoscopic perovskite solar cells using ruthenium‐doped TiO2 electron transporting layer

“…On the other hand, the c ‐TiO 2 layer is prone to the defect trap levels that lead to charge recombination, consequently affecting the electron transport and hence the charge collection efficiency. To address the above issue and to further improve the overall performance, the mp ‐TiO 2 has been doped with metals such as Li, Sn, and Nb 17–20 . However, it has resulted in low electron mobility due to the porous nature of mp ‐TiO 2 .…”

“…To avoid such a scenario, the mp ‐TiO 2 could be replaced with Al 2 O 3 or ZrO 2 layer as an insulating scaffold layer 14,21 . In another approach, metal‐doped (Mg, Sn, Nb, Li, Ta, Al, and Ga) compact TiO 2 has been used as a promising ETLs for HPSCs 19–26 . Besides, recently, Mg and Cs doped ZnO 27,28 and Cs:TiO 2 29,30 have been used as ETLs for inorganic PSCs to improve the device performance and stability of the unstable perovskite layer.…”

“…To address the above issue and to further improve the overall performance, the mp-TiO 2 has been doped with metals such as Li, Sn, and Nb. [17][18][19][20] However, it has resulted in low electron mobility due to the porous nature of mp-TiO 2 . In perovskite solar cells (PSCs), the electron mobility of a compact layer is of major significance because mp-TiO 2 has lower electron mobility than that of the perovskite absorber layer.…”