Enhancing carrier dynamics via phase manipulation of dual-phase all-inorganic perovskites for high-performance photodetectors

Abstract

Cesium lead bromide perovskites have demonstrated enormous potential in detecting applications, benefitting from their excellent optoelectronic properties and environmental stability. However, their intrinsic properties of photoluminescence intensity and carrier lifetime, key to photodetector performance, are still limited with conventional approaches (e.g., material purification and defect passivation). Here, we propose an efficient ultrasound-assisted growth method to manipulate the crystal phase of all-inorganic perovskites. Morphological, structural, and elemental characteristics of perovskites are comprehensively investigated, confirming the formation of CsPb2Br5–CsPbBr3 dual-phase (DP) perovskites. The fabricated DP perovskites exhibit enhanced carrier dynamics compared to CsPbBr3 quantum dots (QDs), including over a tenfold increase in photoluminescence intensity and an extended carrier lifetime of 656 ns. Such impressive improvements originate from the repeated radiative recombination introduced by the hierarchical phase of DP perovskites. As a result, the DP perovskite-based photodetector also demonstrates improved photoresponse, including a larger on/off ratio exceeding 103 and a higher detectivity of 1.48 × 1010 Jones, especially in the absence of conventional transporting layers. These results offer strong competitiveness for state-of-the-art perovskite photodetectors and deliver important implications for the widespread use of DP perovskites in assembling high-performance optoelectronic devices.