Improved efficient perovskite solar cells based on Ta-doped TiO₂nanorod arrays

Abstract

Organometal halide perovskite solar cells (PSCs) are nowadays regarded as a rising star in photovoltaics. In particular, PSCs incorporating oriented TiO nanorod (NR) arrays as the electron transport layer (ETL) have attracted significant attention owing to TiO NR's superior electron transport abilities and its potential in long-term stable PSCs. In addition to improve the electron-transport ability of TiO NRs, the tuning of the band alignments between the TiO NR array and the perovskite layer is also crucial for achieving efficient solar cells. This work describes a facile, one-step, solvothermal method for the preparation of tantalum (Ta) doped TiO NR arrays for efficient PSCs. It is shown that the trace doping with Ta tunes the electronic structure of TiO NRs by a synergistic effect involving the lower 5d orbitals of the doped Ta ions and the reduced oxygen vacancies. The synergistic tuning of the electronic structure improves the band alignment at the TiO NR/perovskite interface and boosts the short-circuit current and the fill factor. By using the optimized doped TiO NR array as the ETL, a record efficiency of 19.11% was achieved, which is the highest among one-dimensional-array based PSCs.

TiO2 Nanocolumn Arrays for More Efficient and Stable Perovskite Solar Cells

“…[15][16][17] As a result, compromised charge transport efficiency and severe charge recombination at the perovskite/ETL interface was observed. 18 By comparison, well-oriented one-dimension (1-D) TiO2 nanorods/nanowires/nanotubes arrays represent a promising strategy, 14,[18][19][20][21][22][23][24][25][26][27][28][29][30] exhibiting less surface defects and grain boundaries and facilitating precursor pore-filling. 1D TiO2 arrays can thus provide a direct physical conductive paths to extract and transport efficiently carriers generated by the perovskite layer.…”

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

“…For instance, by using yttrium 17 doped TiO 2 as compact layer, the charge extraction process was improved and the planar PSC device achieved a high PCE of 19.3%. Up to now, magnesium, 18 lithium or sodium, [19][20][21][22] samarium, 23 lanthanum, 24 tantalum, 25 uorine, 26 thallium, 27 and other metal [28][29][30] doped TiO 2 have been attempted in perovskite solar cells. Niobium-doped TiO 2 (Nb:TiO 2 ) has been tremendous used in transparent conductive oxides (TCOs), 31 photocatalysis, 32,33 lithium and sodium ion batteries, 34,35 dyesensitized solar cells (DSSCs).…”

Achieving High‐Performance Perovskite Photovoltaic by Morphology Engineering of Low‐Temperature Processed Zn‐Doped TiO2 Electron Transport Layer

“…Many reports have been published to explain the influence and benefit of appropriate doping in TiO 2. [34][35][36][37][38][39] In our early research, we also revealed that Zn-doped TiO 2 can significantly raise the electron extraction ability and align energy level well with perovskite. [28,29] Accordingly, we chose Zn as a dopant and design synthesis route to obtain Zn:LT-TiO 2 NCs.…”