Environment-dependent optical scattering of cuprous oxide microcrystals in liquid dispersions and Langmuir–Blodgett films

Optical properties of semiconductor materials are important for their broad applications, especially when the materials are nano- and micrometer crystals. Here we show that cuprous oxide microcrystals have three extinction peaks that are environment sensitive in the visible-near infrared region. The extinction peaks show a linear blue shift with the increase in refractive index of the surrounding medium. The environment-dependent shift of extinction spectra can also be observed for cuprous oxide in cast films and Langmuir–Blodgett films. The sensitivity of environment-dependent optical behavior depends on the energy of the extinction peaks. Both experimental work and theoretical calculation on the environment-dependent spectra of cuprous oxide microcrystals provide valuable knowledge on these functional semiconductor materials for various applications.