Multifunctional additive enables lead-adsorbing carbon electrodes for perovskite solar cells†

The potential risk of lead (Pb) leakage from lead halide perovskite materials poses a significant challenge in the commercialization of perovskite solar cells (PSCs). To address this issue, a viable strategy involves endowing the materials in PSCs with the ability to immobilize Pb. Herein, we introduce a straightforward technique for carbon-based PSCs that utilizes phosphate as a multifunctional additive, which exhibits both bonding and chemical adsorption effects. A playdough-like carbon material can be made by mixing a phosphate aqueous solution with graphite powder, and then be pressed into shape to serve as the top electrode of PSCs. In addition to good compatibility with small-area PSCs and modules, this versatile carbon electrode effectively mitigates the Pb leakage from damaged devices to a safe level.