Dr. Tunde Blessed Shonde

Direct X-ray detectors that convert X-rays to electrical charges have broad applications in medicine and security screening. Common semiconductors like
silicon and selenium for direct X-ray detectors have limitations in performance, versatility, and cost-effectiveness. Among new materials under investigation, metal halide perovskites demonstrate great potential for X-ray detectors; however, they are limited by low stability and toxicity. Here, we report, for the first time, a stable and eco-friendly zero-dimensional (0D) organic metal halide hybrid (OMHH), (TPAP)2ZnBr4, for efficient X-ray detectors. With molecular sensitization, wherein metal halides (ZnBr42−) act as X-ray absorbers and organic semiconducting components (TPA-P+, 4-(4-(diphenylamino)phenyl)-1-propylpyridin-1-ium) as charge transporters, 0D (TPA-P)2ZnBr4 detectors exhibit an impressive sensitivity of 2,292 μC Gyair−1
cm−2 at 20 V and a low detection limit of 37.5 nGyair s−1. The exceptional stability of 0D (TPA-P)2ZnBr4 facilitates remarkably stable direct X-ray detection and shows the tremendous potential of rationally designed 0D OMHHs as new-generation radiation detection materials.

Metal halide perovskite nanocrystals have shown tremendous potential for application in light-emitting diodes (LEDs) due to their unique and remarkable optoelectronic properties. Here, we report the development of CsPbBr3 nanoplatelets (NPLs) with surface passivation by organic semiconducting ligands for blue LEDs. The use of two organic salts, triphenyl (9-phenyl-9H-carbazol-3-yl) phosphonium sulfate (TPPcarz(2)SO(4)) and triphenyl (9-phenyl-9H-carbazol-3-yl) phosphonium bromide (TPPcarzBr), as surface treatment agents allows for the preparation of 300 nm size CsPbBr3 NPLs with a blue emission peaked at 455 nm and a photoluminescence quantum efficiency (PLQE) of 82%. Moreover, the charge-transporting TPPcarz+ units improve the conductivity of thin films based on CsPbBr3 NPLs and the band edge alignments for blue LEDs. As a result, blue LEDs based on these CsPbBr3 NPLs exhibit high external quantum efficiencies (EQEs) of up to 4.15%, a maximum luminance of 1511 cd m(-2), and a half-lifetime of 50 min (at 100 cd/cm(2)).