Browsing by Author "Pramod, Ashna K."

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    Enhanced Photoluminescence Quantum Yield, Lifetime, and Photodetector Responsivity of CsPbBr3 Quantum Dots via Antimony Tribromide Post-Treatment
    (2022) Subramaniam, Mohan Raj; Pramod, Ashna K.; Hevia, Samuel A.; Batabyal, Sudip K.
    Herein, we present the synthesis of CsPbBr3 quantum dots (QDs) by a ligand-assisted reprecipitation (LARP) technique under an ambient atmosphere. Besides, the optoelectronic properties of CsPbBr3 QDs were improved through antimony tribromide (SbBr3) post-treatment. Photoluminescence quantum yield (PLQY) was enhanced from 72 to 89% for SbBr3 post-treated QDs compared to as-synthesized QDs. High-resolution transmission electron microscopy (HR-TEM) analysis shows the formation of uniform-size CsPbBr3 QDs (9.4 +/- 1.3 nm) after SbBr3 treatment. The X-ray diffraction (XRD) pattern confirms the presence of the cubic phase of CsPbBr3 QDs before and post-treatment. Moreover, temperature-dependent PL and X-ray photoelectron spectroscopy (XPS) characterizations confirm the effective defect passivation with SbBr3 post-treatment. The time-resolved PL lifetime of CsPbBr3 QDs was enhanced from 24.80 +/- 0.10 to 37.71 +/- 0.09 ns after post-treatment. Finally, the post-treated QD-based self-powered photodetector device showed a high responsivity of 48 mu A/W compared to the as-synthesized QD device's responsivity of 10.2 mu A/W.
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    Synthesis of lead-free Cs3Sb2Cl3Br6 halide perovskite through solution processing method for self-powered photodetector applications
    (2022) Pramod, Ashna K.; Subramaniam, Mohan Raj; Hevia, Samuel A.; Batabyal, Sudip K.
    Herein, the present study focus on synthesis of lead-free Cs3Sb2Cl3Br6 microcrystals via a simple solution processing method. X-ray diffraction (XRD) and transmission electron microscopy (TEM) analysis confirms the formation hexagonal phase of Cs3Sb2Cl3Br6 perovskite. Scanning electron microscopy (SEM) and TEM morphology reveals the presence of hexagonal shape of Cs3Sb2Cl3Br6 microcrystals. UV-Vis diffuse-reflectance spectroscopy (UV-Vis DRS) endorse the formation of 2.55 eV direct bandgap Cs3Sb2Cl3Br6. A lateral type selfpower photodetector was fabricated via cost-effective method using Cs3Sb2Cl3Br6 and carbon materials and it shows a fast ON and OFF (0.92 s & 0.70 s) with a high responsivity of 1 mu A/W at zero bias.