Stability and photocurrent enhancement of photodetectors by using core/shell structured CsPbBr/TiO quantum dots and 2D materials.

Ultra-stable CsPbBr perovskite quantum dots (QDs) were prepared, and the performance of the photodetector fabricated from them was enhanced by 2D material incorporation. This multi-component photodetector appears to have good stability in the ambient utilization environment. All inorganic CsPbBr QDs are potential candidates for application in photodetection devices. However, QDs have several issues such as defects on the QD surface, degradation under environmental conditions, and unfavorable carrier mobility limiting the high performance of the photodetectors. This work addresses these issues by fabricating a core/shell structure and introducing 2D materials (MXenes, TiCT) into the device. Here, three types of photodetectors with QDs only, QDs with a core/shell structure, and QDs with a core/shell structure and MXenes are fabricated for systematic study. The CsPbBr/TiO photodetector demonstrated a two times photocurrent enhancement compared to bare QDs and had good device stability after TiO shell coating. After introducing TiCT into CsPbBr/TiO, a significant photocurrent enhancement from nanoampere (nA) to microampere (μA) was observed, revealing that MXenes can improve the photoelectric response of perovskite materials significantly. Higher photocurrent can avoid signal interference from environmental noise for better practical feasibility. This study provides a systematic understanding of the photocurrent conversion of perovskite quantum dots that is beneficial in advancing optoelectronic device integration, especially for flexible wearable device applications.