UV-Stable and Highly Efficient Perovskite Solar Cells by Employing Wide Band gap NaTaO₃ as an Electron-Transporting Layer

Abstract

Organic–inorganic halide perovskite solar cells (PSCs) still suffer from stability issues which are caused by possible erosions from moisture, ultraviolet (UV) light, heat, and so forth. An electron-transporting layer (ETL), that is, TiO2, is a key component for state-of-the-art PSCs. However, UV-caused desorption of O2– in TiO2 would accelerate the degradation of PSCs. Herein, we explored perovskite oxide, NaTaO3, for the first time as an alternative ETL in PSCs. NaTaO3 as an ETL can effectively avoid the damage from UV irradiation, inhibit the degradation of the perovskite layer, and improve the overall stability of the PSC. PSCs fabricated with NaTaO3 yielded a power conversion efficiency (PCE) of 21.07% with a retention of more than 80% of this initial PCE after 240 min UV irradiation in air while the reference device with a PCE of 20.16% can only retain about 53% of its initial PCE after the same testing condition. The developed stable perovskite oxide material of NaTaO3 provides the diversification of electron-selective contact for highly efficient and stable PSCs.

Photodegradation of Triple-Cation Perovskite Solar Cells: The Role of Spectrum and Bias Conditions

“…Moreover, the higher the energy of incident UV radiation, the greater is the degradation . Thus, the current understanding of UV stability of PSCs proposes that, if UV radiation is blocked effectively, the PSCs should become photostable. , However, this is often not encountered in practice, as demonstrated by exposing unencapsulated PSCs to radiation of a UV-free white light-emitting diode (LED) at 20 °C in an inert atmosphere for 250 h where a loss of more than 20% in efficiency is observed . This observed instability of PSCs toward UV-filtered light suggests that other parts of the solar spectrum could also be contributing to the photo-degradation of PSCs.…”

Shape‐Controlled NaTaO3 by Flux‐Mediated Synthesis

“…[39] Ye et al suggested an improvement in the efficiency of PSCs with NaTaO 3 through thickness control of the NaTaO 3 layer and in combination with a thin modified layer of phenyl-C61-butyric acid methyl ester between the perovskite and the NaTaO 3 layer. [39] Here however, we want to take advantage of the chemical tunability of NaTaO 3 , and by targeted choice of their constituent elements, vary shape and surface composition and test their corresponding device performance. As illustrated in Figure 4b the NaTaO 3 samples are slightly lower than that of FAPbI 3 (−3.79 eV), and their VBMs are significantly lower than that of FAPbI 3 (−5.38 eV).…”

“…[ 35–38 ] Recently, solution‐processed NaTaO 3 nanoparticles as an electron transport layer (ETL) have been reported in PSCs. [ 39 ] Ye et al. suggested an improvement in the efficiency of PSCs with NaTaO 3 through thickness control of the NaTaO 3 layer and in combination with a thin modified layer of phenyl‐C61‐butyric acid methyl ester between the perovskite and the NaTaO 3 layer.…”

“…[35][36][37][38] Recently, solutionprocessed NaTaO 3 nanoparticles as an electron transport layer (ETL) have been reported in PSCs. [39] Ye et al suggested an improvement in the efficiency of PSCs with NaTaO 3 through thickness control of the NaTaO 3 layer and in combination with a thin modified layer of phenyl-C61-butyric acid methyl ester between the perovskite and the NaTaO 3 layer. [39] Here however, we want to take advantage of the chemical tunability of NaTaO 3 , and by targeted choice of their constituent elements, vary shape and surface composition and test their corresponding device performance.…”

Doping in Semiconductor Oxides‐Based Electron Transport Materials for Perovskite Solar Cells Application

“…Except for the common ternary semiconductor oxides mentioned earlier, SrSnO 3 , [ 156 ] BaTiO 3 , [ 157 ] NaTaO 3 , [ 158 ] and Ti 0.5 Fe 0.5 O x [ 159 ] have also been reported in PSCs. In summary, ternary semiconductor oxides seem to induce faster crystallization, high transparency, and better surface coverage for perovskite layers.…”