Adsetts Jonathan Ralph, Hoesterey Salena, Gao Chenjun, Love David A, Ding Zhifeng
Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, London, Ontario N6A 5B7, Canada.
Rosstech Signal Inc., 71 15th Line South, Orillia, Ontario L3 V 6H1, Canada.
Langmuir. 2020 Dec 1;36(47):14432-14442. doi: 10.1021/acs.langmuir.0c02886. Epub 2020 Nov 18.
Carbon quantum dots (CQDs) show promise in optoelectronics as a light emitter due to simple synthesis, biocompatibility and strong tunable light emissions. However, CQDs commonly suffer from aggregation caused quenching (ACQ), inhibiting the full potential of these light emitters. Studies into different ideal light emitters have shown enhancements when converting common ACQ effects to aggregation induced emission (AIE) effects. We report CQD synthesis using citric acid and high/low thiourea concentrations, or sample 2/1. These two CQDs exhibited AIE and ACQ PL effects, respectively. CQD characterizations and photoluminescence interrogations of CQD films and solutions revealed that these unique emission mechanisms likely arose from different S incorporations into the CQDs. Furthermore, it was discovered that sample 2 emitted electrochemiluminescence (ECL) more intensely than sample 1 in a homogenous solution with SO as a coreactant, due to aggregation and interactions of CQD species in solution. Very interestingly, sample 1's CQD film|SO system achieved an ECL efficiency of 26% and emitted roughly 26 times more efficiently than sample 2 in the same conditions. Predominant interfacial reactions and surface state emission produced intense white light with a correlated color temperature of 2000 K. Spooling ECL spectroscopy was utilized to investigate emission mechanisms. Sample 2's CQD film|TPrA system had four times higher ECL intensity than that of sample 1, most likely due to π-cation interactions leading to a strong CQD stability, thereby, enhancing ECL. It is anticipated that ECL enhancement of CQD films or solutions by means of AIE will lead to wide CQD optoelectronic applications.
碳量子点（CQDs）由于合成简单、具有生物相容性和强烈的可调谐发光特性，在光电子学领域作为发光体展现出了应用前景。然而，碳量子点通常会因聚集导致猝灭（ACQ），这限制了这些发光体的全部潜力。对不同理想发光体的研究表明，当将常见的ACQ效应转化为聚集诱导发光（AIE）效应时，发光性能会得到增强。我们报道了使用柠檬酸和高/低硫脲浓度（即样品2/1）合成碳量子点的方法。这两种碳量子点分别表现出AIE和ACQ的光致发光（PL）效应。对碳量子点薄膜和溶液的表征以及光致发光研究表明，这些独特的发射机制可能源于不同的硫原子掺入到碳量子点中。此外，研究发现，在以SO作为共反应剂的均匀溶液中，样品2比样品1发射出更强的电化学发光（ECL），这是由于溶液中碳量子点物种的聚集和相互作用。非常有趣的是，在相同条件下，样品1的碳量子点薄膜|SO体系实现了26%的ECL效率，其发光效率比样品2高出约26倍。主要的界面反应和表面态发射产生了相关色温为2000 K的强烈白光。利用卷绕式ECL光谱研究发射机制。样品2的碳量子点薄膜|TPrA体系的ECL强度比样品1高四倍，这很可能是由于π-阳离子相互作用导致碳量子点具有很强的稳定性，从而增强了ECL。预计通过AIE增强碳量子点薄膜或溶液的ECL将导致碳量子点在光电子学领域得到广泛应用。
