Mechanism for fluorescence quenching of CdS quantum dots in presence of 2‐Amino‐7‐Nitrofluorene (ANF) and 2‐(N,N‐dimethylamino)‐7‐Nitrofluorene (DMANF) has been investigated using steady‐state and time‐resolved fluorescence spectroscopy. Lowering of emission intensity along with a reduction in average lifetime of CdS quantum dots has been observed with addition of both ANF and DMANF. This quenching is also accompanied with an enhancement in the emission intensity of ANF and DMANF. From these observations, resonance energy transfer is anticipated to take place in the present case. However, a careful analysis of rate constants, Stern‐Volmer plot, steady‐state and lifetime decay profiles showed that the quenching is observed not due to energy transfer, rather due to other competing processes like static quenching and photoinduced charge transfer between the dyads. The high bimolecular quenching rate constants estimated from Stern‐Volmer plot support the presence of static quenching of CdS quantum dots. Analysis of redox potential values of CdS quantum dots, ANF and DMANF has shown the possibility for photoinduced charge transfer in the present systems.

中文翻译：

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2-氨基-7-硝基芴和2-（N，N-二甲基氨基）-7-硝基芴对CdS量子点的荧光猝灭机理研究

使用稳态和时间分辨荧光研究了在2-氨基-7-硝基芴（ANF）和2-（N，N-二甲基氨基）-7-硝基芴（DMANF）存在下CdS量子点的荧光猝灭机理光谱学。通过同时添加ANF和DMANF，可以观察到发射强度的降低以及CdS量子点平均寿命的降低。该猝灭还伴随着ANF和DMANF的发射强度的增强。从这些观察结果，预计在当前情况下会发生共振能量转移。但是，仔细分析速率常数，Stern-Volmer图，稳态和寿命衰减曲线后发现，淬火并不是由于能量转移引起的，而是由于其他竞争过程，例如静态猝灭和二元组之间的光诱导电荷转移。根据Stern-Volmer图估算的高双分子猝灭速率常数支持CdS量子点的静态猝灭。对CdS量子点，ANF和DMANF的氧化还原电势值的分析显示了在本系统中光诱导电荷转移的可能性。