Efficient Gradient Potential Top Electron Transport Structures Achieved by Combining an Oxide Family for Inverted Perovskite Solar Cells with High Efficiency and Stability

Abstract

Although inverted (p–i–n) structure perovskite solar cells (PSCs) have achieved high efficiency by commonly using fullerenes or their derivatives as electron transport layers (ETLs), the device stability and cost of fullerene materials are still of great concern. Herein, we demonstrate inorganic top ETLs simply composed from a family of metal oxides including In2O3 and its derivative of Sn:In2O3 with a gradient potential structure. For inverted PSCs, the typical film formation process of In2O3 will damage or degrade perovskite materials underneath; thus, we report a low temperature synthesis approach for obtaining In2O3 and Sn:In2O3 nanoparticles that can form effective top ETLs without any post-treatment. The one-family oxide-based top ETL features with the enhanced built-in potential, high electron extraction, and low interfacial recombination, offering a power conversion efficiency (PCE) of 20.65% in PSCs constructed from oxide-only carrier (both hole and electron) transport layers (CTLs), which is the highest efficiency in oxide-only CTL-based inverted PSCs to the best of our knowledge. Equally important, the inverted PSCs based on the Sn:In2O3/In2O3 ETL show the excellent operational stability and remain 90% of the initial value of PCE over 2000 h. Consequently, this work contributes to the robust strategy of all oxide-only CTLs in developing rigid and flexible PSCs for practical photovoltaic applications.

Metal Oxide-Induced Instability and Its Mitigation in Halide Perovskite Solar Cells

“…The authors showed that the NiO x /FAMAPbI 3 /Sn–In 2 O 3 /In 2 O 3 device can deliver PCE of 20.7% with negligible hysteresis. Importantly, this device exhibited excellent thermal stability and photostability over 2000 h of operation . This work also showed the potential of developing all oxide-based HTL and ETL p-i-n devices.…”

“…Importantly, this device exhibited excellent thermal stability and photostability over 2000 h of operation. 83 This work also showed the potential of developing all oxide-based HTL and ETL p-i-n devices. However, without mitigating the detrimental interactions at the NiO x /perovskite interface, because NiO x is particularly notorious for triggering interfacial degradation, any efforts to boost the operational stability of such PSCs will be futile.…”

Growth Temperature Influence on Atomic-Layer-Deposited In2O3 Thin Films and Their Application in Inorganic Perovskite Solar Cells

“…Contrarily, the modified ETL to ALD-In 2 O 3 can effectively improve the device's performance. Figure 8c Usually, the high conductivity of ETL may cause current leakage, and may this could be a possible reason for the drop of J SC at ≤200 • C. Whereas, at 250 • C, increased J SC is mainly attributed to an enhanced electron extraction at the ETL/perovskite interface, including reduced charge recombination contributing to remarkably enhanced FF [46].…”

Recent Advances in Inverted Perovskite Solar Cells: Designing and Fabrication

“…The removal of organic components and the application of inorganic ETL are effective methods to improve thermally stable of inverted PSCs. The n−type semiconductor materials were surveyed and employed to replace organic ETL for inverted devices, such as ZnO and CdS, as is shown in Table 19 [ 212 , 213 , 214 , 215 , 216 , 217 , 218 , 219 , 220 , 221 , 222 , 223 , 224 , 225 , 226 ]. In 2016, You et al applied the n−type ZnO nanoparticles as ETL to resist the water and oxygen degradation [ 212 ].…”