Size-dependent thermochromism through enhanced electron-phonon coupling in 1 nm quantum dots

1 nm CuO quantum dots (QDs) were produced in size-controlled super-micropores of a silica matrix. The reversible color change of the QDs from pale blue to deep green was clearly observed in a wide temperature range from 298 to 673 K. This particular thermochromism is ascribed to an enhanced bandgap shift depending on temperature with a strong electron-phonon coupling in the confined space of the 1 nm QDs. A dot matrix: 1 nm CuO quantum dots have been prepared in microporous silica. They exhibit unique and reversible color change from pale blue to deep green in a wide temperature range from 298 to 673 K. This thermochromism is ascribed to an enhanced bandgap shift that depends on temperature, with a strong electron-phonon coupling in the confined space of the 1 nm CuO quantum dots.