International researchers have placed a low-dimensional metal-halide perovskite capping layer on top of a metal-halide perovskite film to provide hermetically sealed encapsulation and enhanced photocarrier properties. The cell has a short-circuit current density of 23.5 mA.cm2, an open-circuit voltage of 1.15 V, and a fill factor of 0.779.<\/p>\n\n\n\n

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An international group of researchers has developed a flexible thin-film perovskite solar cell with an efficiency of 21.0%.<\/p>\n\n\n\n

The perovskite layer for the cell, which has an \u201cn-i-p\u201d layout<\/a>, was fabricated with a metal-halide capping layer placed on top of a three-dimensional metal-halide perovskite<\/a> film. This design provide hermetically sealed encapsulation, which is traditionally difficult in flexible perovskite cells, and also enhances the photocarrier properties at the interface between the perovskite film and the hole transport layer (HTL).<\/p>\n\n\n\n

\u201cThis low-dimensional (LD) MHP capping layer not only reduces the propensity for fracture in bending but also provides protection against ingression of environmental species,\u201d they explained in \u201cFlexible perovskite solar cells with simultaneously improved efficiency, operational stability, and mechanical reliability<\/a>,\u201d which was recently published in Joule<\/em>.<\/p>\n\n\n\n

The MHP precursor was deposited through spin-coating<\/a> on substrates made of fluorinated tin-oxide (FTO) and glass, followed by thermal annealing at 100 C. The perovskite layer was then sandwiched between a tin(IV) oxide (SnO_{2<\/sub>)<\/a> electron transport layer (ETL) and an HTL made of} Spiro-OMeTAD<\/a>. Indium tin oxide (ITO) and silver (Au) were used as conducting electrodes on either side of the cell.<\/p>\n\n\n\n

The device showed a short-circuit current density of 23.5 mA.cm^{2<\/sup>, an open-circuit voltage of 1.15 V, a fill factor (FF) of 0.779, and a power conversion efficiency of 21.0%. The academics described these results as unprecedented. A cell with the same architecture but without the LD MHP capping exhibited an efficiency of 18.4%. The cell with LD MHP capping also showed a degradation to only 90% of the initial efficiency after 800 hours, while the device without capping degraded to 79% after 475 hours.<\/p>\n\n\n\n}

The researchers also analyzed the solar cell through cyclic bend testing and found that LD\/3D MHP thin films have \u201cunprecedented\u201d bending durability, as the cells can retain 81% of their initial efficiency after 20,000 cycles. This value for the cells without the capping layer was just 54%.<\/p>\n\n\n\n

\u201cThis resistance to cracking in LD\/3D MHP thin films has cascading beneficial effects,\u201d the researchers said. \u201cFirst, the LD MHP capping layer, in addition to protecting the underlying 3D MHP thin film from environmental degradation, reduces cracking in the 3D MHP thin film, which further prevents environmental attack.\u201d<\/p>\n\n\n\n

The research group included scientists from\u00a0Brown University<\/a>\u00a0in the United States and\u00a0\u00c9cole polytechnique f\u00e9d\u00e9rale de Lausanne<\/a>, as well as the\u00a0Dalian University of Technology<\/a>\u00a0and\u00a0Shaanxi Normal University<\/a>\u00a0in China.<\/p>\n\n\n\n

From: https:\/\/www.pv-magazine.com\/2021\/06\/14\/flexible-perovskite-solar-cell-with-21-0-efficiency-high-durability\/<\/p>\n","protected":false},"excerpt":{"rendered":"

International researchers have placed a low-dimensional metal-halide perovskite capping layer on top of a metal-halide perovskite film to provide hermetically sealed encapsulation and enhanced photocarrier properties. The cell has a short-circuit current density of 23.5 mA.cm2, an open-circuit voltage of 1.15 V, and a fill factor of 0.779. An international group of researchers has developed…
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