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A Comparative Study on the Photovoltaic Properties of ZnX (X=S, Se, Te) QD/CNT Inorganic/Organic Hybrid Nanocomposites
摘要： Designing the efficient inorganic/organic hybrid light harvesting systems through understanding of charge generation, separation and recombination dynamics is an important pathway for improvement of power conversion efficiency (PCE) of photovoltaic cell. Using density functional method, we explored the photovoltaic performance of recently synthesized ZnX (X=S, Se, Te) QD/carbon nanotube (CNT) nanocomposites. Interestingly, ZnX QD/CNT nanocomposites exhibit type-II band alignment, where hole and electron charge carriers are localized on ZnX QD and CNT, respectively. However, the energy difference between highest occupied molecular orbital of ZnXQD and conduction band minimum of CNT is very small (0.09-0.26 eV), implying huge possibilities of electron-hole recombination at ZnX:CNT interface. To overcome such unpleasant situation, we focus on chemical modification of CNT. The CNT is hydrogenated by attachment of atomic hydrogen and next the hydrogenated CNT is functionalized by electron withdrawing group (-CN) in part. We found that ZnX QD and CN functionalized hydrogenated CNT nanocomposites exhibit intended type-II band alignment and achieve high PCEs in the range of 6.73-8.38%, making them exceptionally competitive with other previously reported hybrid solar cells.
关键词： inorganic/organic hybrid nanocomposites,power conversion efficiency,ZnX QD/CNT,type-II band alignment,photovoltaic properties
更新于2025-09-23 15:19:57
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Simultaneous positive and negative optical patterning with dye-sensitized CdSe quantum dots
摘要： CdSe quantum dots are functionalized with the organic dye iron β-tetraaminophthalocyanine to reward a solution-processable hybrid material with two individually addressable optical resonances. We exploit this dual functionality during optical write/optical read patterning experiments and show that it is possible to simultaneously write complex optical patterns with positive and negative fluorescence contrast. This is enabled by a fluorescence enhancement under near-resonant excitation of the quantum dots in combination with a fluorescence bleaching during excitation of the singlet transition of the phthalocyanine. The presence of the organic dye not only enables negative optical patterning but also enhances the contrast during positive patterning. Furthermore, the patterning result is strongly dependent on the excitation wavelength during readout. Our results highlight the new possibilities that arise from combining inorganic quantum dots and organic π-systems into hybrid nanocomposites.
关键词： fluorescence contrast,optical patterning,iron β-tetraaminophthalocyanine,CdSe quantum dots,hybrid nanocomposites
更新于2025-09-12 10:27:22
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Hybrid Dielectric-Plasmonic Nanocomposite Arrays for Bulk and Local Refractive Index Sensing
摘要： Plasmonics-based biosensors are often limited by material losses in the form of joule heating while all dielectric nanoparticles systems have relatively smaller local electric field enhancements. For efficient sensing, it is desirable to have a system with high sensitivity but with minimal losses. Here, we demonstrate, using numerical simulations, the capability of a hybrid dielectric-plasmonic system for refractive index sensing applications. We show that the optical resonances of such a hybrid system have smaller linewidths and the peak wavelengths are tunable. Bulk as well as local refractive index sensing are demonstrated in this work. Owing to large sensitivities of 300 nm/RIU with a figure of merit (FOM) of 10, the hybrid photonic-plasmonic systems presented here are promising materials for future biosensing applications.
关键词： Dielectric nanoparticle arrays,Hybrid nanocomposites,Plasmonic sensing
更新于2025-09-12 10:27:22