Bismuth Telluride Interlayer for All‐Inorganic Perovskite Solar Cells with Enhanced Efficiency and Stability. Issue 12 (8th August 2019)

• Record Type: Journal Article
• Authors: Fu, Lin; Nie, Yingjian; Li, Bo; Li, Ning; Cao, Bingqiang; Yin, Longwei
• Is Part Of: Solar RRL. Volume 3:Issue 12(2019)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2019-08-08
• Subjects: Bi2Te3 -- charge transport -- inorganic perovskite -- interface engineering -- stability; Solar energy -- Periodicals; Photovoltaic power generation -- Periodicals; Solar energy -- Research -- Periodicals; Photovoltaic power generation -- Research -- Periodicals; Periodicals; 333.7923
• DOI: 10.1002/solr.201900233
• Languages: English
• ISSNs: 2367-198X

Abstract

Abstract : To solve the thermal instability issue of organic–inorganic hybrid perovskites, all‐inorganic perovskite solar cells (PSCs) have been featured in the spotlight. However, their power conversion efficiencies (PCEs) are far from satisfactory due to the substantially radiative and nonradiative recombination of charge carriers in the common‐structured devices. Herein, bismuth telluride (Bi2 Te3 ) nanoplates are designed as an interlayer between cesium lead halide (CsPbBrI2 ) and 2, 2′, 7, 7′‐tetrakis( N, N ‐di‐p‐methoxyphenylamine)‐9, 90‐spirobifluorene (Spiro‐OMeTAD) to reduce the notorious trap states and charge recombination. Confirmed by systematic electrochemical and photoelectrical techniques, the Bi2 Te3 interlayer optimizes hole extraction and transport efficiency because of the matched band level structure and drastically reduces trap defect densities. Prolonged effective lifetime and shorter diffusion time induced by the Bi2 Te3 interlayer reveal less electron–hole recombination and more efficient carrier transport, which lead to a larger photocurrent and less open circuit voltage loss of PSCs. The all‐inorganic PSCs with the optimal Bi2 Te3 interlayer exhibit a highly enhanced PCE of 11.96%. Moreover, Bi2 Te3 also acts as a blocking layer for the migration of iodide ions, silver, and moisture, resulting in a considerable device stability of more than 70% of initial PCE after 50 days without extra encapsulation. This low‐cost and facile method for efficient and stable all‐inorganic PSCs offers great promise as a next‐generation renewable energy source. Abstract : Bi2 Te3 nanoplates with a tunable energy structure are introduced in inorganic perovskite solar cells (PSCs), accelerating hole transport by the matched band alignment. Confirmed by systematic measurements, charge recombination is largely suppressed due to lower trap density and higher carrier mobility. The optimal PSC with Bi2 Te3 exhibits highly decreased V OC loss and enhanced long‐term stability over 50 days.