Dependence of the Heterogeneity of Grain Boundaries on Adjacent Grains in Perovskites and Its Impact on Photovoltage. Issue 8 (11th December 2021)

• Record Type: Journal Article
• Authors: Yao, Wenlong; Fang, Shuyan; Hu, Ziyang; Huang, Like; Liu, Xiaohui; Zhang, Houcheng; Zhang, Jing; Zhu, Yuejin
• Is Part Of: Small. Volume 18:Issue 8(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-12-11
• Subjects: grain boundaries -- heterogeneity -- perovskite solar cells -- photoconductive atomic force microscopy -- photovoltage; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202105140
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: In polycrystalline perovskites, grain boundaries (GBs) that isolate grains determine the optoelectronic properties of a semiconductor, and hence affect the photovoltaic performance of a solar cell. Photocurrent and photovoltage are affected by the microscopic structure of perovskites but are difficult to quantify on the intragrain length scale and are often treated as homogeneous within the photoactive layer. Here, the nanoscale through‐film and lateral photoresponse of large‐grained perovskite are studied by photoconductive atomic force microscopy. Photocurrent collection along GBs relies on the formation of adjacent grains, exhibiting GB to GB heterogeneity. Regarding to the spatially correlated heterogeneity, the photovoltage of grains deduced from the photoresponse curves at specific positions is larger than that of GBs by up to 0.4 V, suggesting that the photovoltage loss mainly originates from the shunting of GBs through the whole perovskite layer. These spatial heterogeneities are alleviated by depositing a capping layer onto the perovskite layer, highlighting the role of the inserted layer between the perovskite and electrode in real solar cells. This research reveals the heterogeneity of GBs and its influence on photovoltage that actually occurs in virtual solar cells, which is crucial for optimizing perovskite‐based solar cells. Abstract : In polycrystalline perovskites, the nanoscale photoconduction measurements indicate that photocurrent collection along grain boundaries (GBs) is dependent on adjacent grains, exhibiting GB to GB heterogeneity. The photovoltage loss mainly originates from the shunting of GBs relative to the whole perovskite. This research reveals the heterogeneity of GBs and its influence on photovoltage, which is crucial for optimizing perovskite‐based solar cells.