Chelating resin encapsulation for reduced Pb leakage in perovskite solar cells

Although perovskite solar cells have achieved efficiency over 25%, the toxic of Pb content remains severe problem given its commercial prospect. Especially when the devices suffer harsh weather, the Pb content can easily leak out to soil and water. Chelating resins (CRs) exhibit excellent superiority in treating waste water in industrial field, since the functional groups in CRs can adsorb divalent metal ion to soften and purify waste water. Herein, an iminodiacetic acid (IDA)-CR is introduced as encapsulation over perovskite solar cells for the first time. The IDA-CR exhibits high surface area and excellent adsorption capability. Qualitative and quantitative analysis of Pb leakage are studied, and the devices with encapsulation of IDA-CR can detain over 90% of Pb compared with control devices without encapsulation after immersed in deionized water for 12 h even in acid situation or after heating. This IDA-CR method provides a new strategy towards environmental and biological-friendly perovskite optoelectronic devices.