Proceedings of International Conference on Perovskite and Organic Photovoltaics and Optoelectronics (IPEROP19)
Publication date: 23rd October 2018
Facile electron extraction and transport are an important feature in electron transport layers (ETLs) for enhancing the efficiency of planar perovskite solar cells (PSCs). Herein, we consider the effects of different TiO2 polymorphs such as anatase and brookite. We design and fabricate high-phase purity and low-temperature (<180 °C) processed brookite based TiO2 heterophase junctions by comprising two phases in the differing phase on FTO-substrates, particularly, anatase–brookite (AB) and brookite–anatase (BA). We attempt to compare single-phase anatase (A) and brookite (B) and heterophase (AB) and (BA) as ETLs in PSCs. The power conversion efficiencies (PCEs) of PSCs with low-temperature processed single layer FTO-B as the ETL were as high up as 14.92% that is the top reported efficiency of single-layer FTO-B-based PSC.1 Consequently, the single layer FTO-B exhibits as an active phase and can be a potential candidate as an n-type ETL scaffold in planar PSCs. Ultimately, the champion device with heterophase junction FTO-AB structure ETL exhibited PCE of 16.82% that is higher to those of PSCs with FTO-A and FTO-B as the ETLs (13.86% and 14.92%, respectively). Furthermore, the PSCs with FTO-AB showed enhanced efficiency and significant decreased in J-V hysteresis compared with FTO-BA (13.45%) owing to the suitable match with the perovskite layer that resulted in higher capability of photogenerated charge carrier extraction and reduced charge accumulation at the interface of the heterophase junction/perovskite. Therefore, this work yields an effective strategy to develop heterophase junction ETLs and manipulating the interfacial energy band for further improving planar PSCs performance and enable clean, and eco-friendly fabrication of low-cost mass production.
1. Shahiduzzaman, M.; Visal, S.; Kuniyoshi, M.; Kaneko, T.; Umezu, S.; Katsumata, T.; Iwamori, S.; Kakihana, M.; Taima, T.; Isomura, M.; Tomita, K. Nano Lett. 2018.
This study was supported in part by Research and Study Project of Tokai University General Research Organization.