In the same way as electron transport is crucial for information technology, ion transport is a key phenomenon in the context of energy research. To be able to tune ion conduction by light would open up opportunities for a wide realm of new applications, but it has been challenging to provide clear evidence for such an effect. Here we show through various techniques, such as transference-number measurements, permeation studies, stoichiometric variations, Hall effect experiments and the use of blocking electrodes, that light excitation enhances by several orders of magnitude the ionic conductivity of methylammonium lead iodide, the archetypal metal halide photovoltaic material. We provide a rationale for this unexpected phenomenon and show that it straightforwardly leads to a hitherto unconsidered photodecomposition path of the perovskite.

就像电子传输对于信息技术至关重要一样，离子传输是能源研究中的关键现象。能够调节光的离子传导将为广泛的新应用开辟机会，但是为这种效应提供清晰的证据一直具有挑战性。在这里，我们通过各种技术（例如迁移数测量，渗透研究，化学计量变化，霍尔效应实验和使用阻挡电极）表明，光激发将甲基铵碘化铅（原型金属）的离子电导率提高了几个数量级。卤化物光伏材料。我们为这种意外现象提供了理论依据，并表明它直接导致了钙钛矿迄今为止从未考虑过的光分解路径。