Optical Properties of Perovskite‐Organic Multiple Quantum Wells

A comprehensive study of the optical properties of CsPbBr3 perovskite multiple quantum wells (MQW) with organic barrier layers is presented. Quantum confinement is observed by a blue‐shift in absorption and emission spectra with decreasing well width and agrees well with simulations of the confinement energies. A large increase of emission intensity with thinner layers is observed, with a photoluminescence quantum yield up to 32 times higher than that of bulk layers. Amplified spontaneous emission (ASE) measurements show very low thresholds down to 7.3 µJ cm−2 for a perovskite thickness of 8.7 nm, significantly lower than previously observed for CsPbBr3 thin‐films. With their increased photoluminescence efficiency and low ASE thresholds, MQW structures with CsPbBr3 are excellent candidates for high‐efficiency perovskite‐based LEDs and lasers. CsPbBr3 perovskite/TPBi organic multiple quantum wells are reported to show charge carrier confinement that results in a massive increase of emission efficiency with stronger confinement. Waveguide formation allows to reach extremely low thresholds of amplified spontaneous emission, which is important for future laser applications.