Chen Jiangzhao et al.: 16.75% Efficiency! Methylammonium-Free Two-Dimensional DJ-Phase Perovskite Solar Cells
Release Date:
2021-07-06 15:27
Source:
Recently, a research team led by Researcher Chen Jiangzhao from the School of Optoelectronic Engineering at Chongqing University published an article titled “Interfacial gradient energy band alignment modulation via ion exchange reaction toward efficient and stable methylammonium-free Dion-Jacobson quasi-2D perovskite solar cells” in the internationally renowned academic journal Journal of Power Sources (a TOP-tier journal). Compared with Ruddlesden–Popper (RP)–type two-dimensional perovskites, Dion–Jacobson (DJ)–type perovskites have garnered increasing attention due to their superior structural stability and enhanced charge-carrier transport properties.
Most previously reported two-dimensional perovskites have employed the methylammonium cation (MA+). MA+-based perovskites often exhibit poor photostability, moisture stability, and thermal stability, which has hindered the commercialization of perovskite solar cells. Chen Jiangzhao and colleagues achieved gradient bromine doping via an in-situ ion-exchange reaction, thereby constructing a graded band alignment. First, this graded band alignment facilitates charge-carrier transport, extraction, and transfer. Second, this strategy improves perovskite crystallization and reduces the defect density in the thin film. Finally, the incorporation of bromine enhances the stability of both the thin film and the device.
As a result, the target device achieved an efficiency of 16.75%, whereas the control device exhibited only 13.78%. The suppression of bulk and interface non-radiative recombination was the primary factor behind the improved device performance. Unencapsulated devices retained 93% of their initial efficiency after 1,600 hours of aging at 15–20% relative humidity and 91% after 400 hours of aging at 60 °C. These findings lay a solid foundation for the commercialization of perovskite solar cells.
Fig. 1. (a) Schematic illustration of the preparation process of (BDA)FA4Pb5I16-xBrx with GBD formed via the ion exchange reaction between I− and Br−. (b) XRD patterns of the perovskite films without and with FABr posttreatment. (c) UV–vis absorption spectra and (d) band gap of the perovskite films without and with FABr treatment. (e) Energy level diagram of PSCs based on the control and target perovskite films. (f) Dark I–V curves of the devices with the structure of ITO/perovskite/Au and ITO/perovskite/FABr/Au.
Literature link:
Pengyu Su #, Le Bai#, Huan Bi, Baibai Liu, Shi Chen, Donghwa Lee, Hua Yang, Cong Chen*, Zhigang Zang, Jiangzhao Chen*. Interfacial gradient energy band alignment modulation via ion exchange reaction toward efficient and stable methylammonium-free Dion-Jacobson quasi-2D perovskite solar cells. Journal of Power Sources 2021, 506, 230213.
https://www.sciencedirect.com/science/article/pii/S0378775321007357?dgcid=author
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