MAPbI₃ Perovskite Multiple Quantum Wells for Enhanced Light Emission and Detection

Multiple quantum wells (MQWs) based on thermally evaporated hybrid perovskite have been demonstrated in type-I and type-II energy band configurations by combining MAPbI3 with bathocuproine (BCP) and lead phthalocyanine (PbPC), respectively. Their optoelectronic properties and charge dynamics have been studied, together with their device potentials. Density functional theory calculations highlighted the major role of surface-localized carriers in ultrathin MAPbI3 and when BCP or PbPC are on top. This restrained charge exchange can reduce the band bending and minimize the disruption of band alignment, confirming the potential of these interlayer materials for MQWs. Furthermore, type-I MQWs show a remarkable increase in photoluminescence intensity (up to 50 times) and a faster radiative recombination rate as MAPbI3 thickness decreases, demonstrating promising light emission capabilities. Type-II MQWs exhibit extended spectral sensitivity and efficient charge separation, significantly improving photodetector performance. This work sets a foundational framework for the further exploration of perovskite MQWs in light-emitting and photodetection applications.