For their formation, cucurbit [n] uril (CB)‐stabilized AgBr nanoparticles are first generated in
water by precipitation. Subsequent irradiation with an electron beam transforms a fraction of
each AgBr nanoparticle into Ag0, leading to well‐defined Janus particles, stabilized by the
binding of CB to the surface of both AgBr and Ag0. With the silver ion reduction being
triggered by the electron beam, the progress of the transformation can be directly monitored …