Photon Upconversion at Crystalline Organic–Organic Heterojunctions

Oldenburg, Michael; Turshatov, Andrey; Busko, Dmitry; Wollgarten, Stephanie; Adams, Michael; Baroni, Nicolò; Welle, Alexander; Redel, Engelbert; Wöll, Christof; Richards, Bryce S.; Howard, Ian A.

doi:10.1002/adma.201601718

Cited by 134 publications

(133 citation statements)

References 24 publications

Supporting

Mentioning

123

Contrasting

Unclassified

Order By: Relevance

“…[6] This study demonstrated that these heterojunctions show solid-state photon upconversion (UC) transforming photons from green to blue (Figure 9). Two different chromophore-based linkers were used: Pd-DCP (Pd(II)5,15diphenyl-10,20-di(4-carboxyphenyl) porphyrin) and ADB (4,4′-(anthracene-9,10-diyl)dibenzoate).…”

Section: Transfer Of Electronic Excitations Across Organic/organic-hementioning

confidence: 86%

“…We especially investigate the specific activation energies for diffusion experiments and for the cisto-trans isomerization of a prototype photo switchable molecule, azobenzene, and we examine the charge transport of electrons. [6] Different LbL techniques, including spray coating, [7] spin coating, [8] and dip coating, [9] can be used for the SURMOF syntheses. Here, the specific advantages of SURMOFs will be highlighted.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Surface‐Mounted Metal–Organic Frameworks: Crystalline and Porous Molecular Assemblies for Fundamental Insights and Advanced Applications

2019

Self Cite

View full text Add to dashboard Cite

with open voids attract significant interest, not only for use in gas storage and separation applications, [1b] but also as model systems used for fundamental investigations on molecular interactions. After being introduced about two decades ago, [2] this new type of crystalline coordination network created considerable excitement and much effort was devoted toward the discovery of new types of these compounds. In early 2017, after 20 years of intense research, the literature contains reports on more than 70 000 structurally characterized examples of this class. [3] Since MOFs can be assembled by combining molecular building blocks, specifically ditopic or higher-topic organic linkers and metal or metal-oxo nodes, a virtually unlimited number of structures can be realized. Moreover, essentially every organic molecule can be modified by the addition of appropriate coupling groups, e.g., carboxylic acid groups or pyridine units, to yield a ditopic linker. Therefore, the number of possible MOF structures is far greater than the number of known structures. In line with this consideration, more than a million of these compounds have been simulated using combinatorial approaches. [4] As MOFs are both crystalline and porous, they have fascinating and often surprising properties. Not only does the immense chemical space spanned by these compounds create enormous potential for advancing materials science, it also provides ideal matrices for reference experiments exploring fundamental spectroscopic and physicochemical properties. The framework provides a well-defined, crystalline, porous environment that can host guest molecules, thus permitting systematic spectroscopic investigations. In contrast to solvents or polymer matrices, MOFs provide a strictly periodic, very well defined structural framework, where the molecular environment is identical for each embedded guest molecule. In this respect, MOFs outperform amorphous noble-gas guest matrices [5] in which the environment surrounding varies from site to site, leading to inhomogeneous broadening of the embedded guest's spectroscopic features, including vibrational bands.Herein, we discuss the use of MOFs and, in particular, of surface-mounted metal-organic frameworks (SURMOFs), to provide well-defined environments for precisely determining Metal-organic frameworks (MOFs) are crystalline coordination polymers, assembled from inorganic nodes connected by organic linker molecules. An enormous surface area, huge compositional variety, regular structure, and favorable mechanical properties are among their outstanding properties. Monolithic MOF thin films, i.e., surface-mounted metalorganic frameworks (SURMOFs), with high degree of structural order and adjustable defect density, can be prepared on solid substrates using layer-by-layer techniques. Recent studies where SURMOFs served as model systems for quantitative studies of molecular interactions in porous media, including diffusion, are reviewed. Moreover, SURMOFs are ideally suited for the incorporation of photoactive mo...

show abstract

Section: Transfer Of Electronic Excitations Across Organic/organic-hementioning

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Surface‐Mounted Metal–Organic Frameworks: Crystalline and Porous Molecular Assemblies for Fundamental Insights and Advanced Applications

2019

Self Cite

View full text Add to dashboard Cite

show abstract

“…Oldenburg et al made a trilayer structure where the sensitizer (Pd(II) 5,15-diphenyl-10,20-di(4-carboxyphenyl) porphyrin light absorber) was sandwiched by the DPA light emitter held together by Zn nodes. 117 While they demonstrated relatively low threshold intensities for the linear regime in their upconversion measurements, the overall upconversion QYs were less than 0.1%, probably because the fluorescence QY of the annihilator layer was only 1.8% (vs. 95% for the free DPA, indicating losses via non-radiative decay pathways), and TET from the donor to the acceptor was severely constrained, possibly due to the lattice mismatch between the 2 layers and roughness/defects in the MOF lattice. In the meantime, Mahato et al synthesized another DPA-containing MOF for photon upconversion, to take advantage of triplet exciton migration between DPA molecules that are closely assembled and aligned.…”

Section: (3) Crystalline Frameworkmentioning

confidence: 99%

Triplet transport in thin films: fundamentals and applications

Tang

2017

Chem. Commun.

View full text Add to dashboard Cite

Triplet excitons are key players in multi-excitonic processes like singlet fission and triplet-triplet annihilation based photon upconversion, which may be useful in next-generation photovoltaic devices, photocatalysis and bioimaging. Here, we present an overview of experimental and theoretical work on triplet energy transfer, with a focus on triplet transport in thin films. We start with the theory describing Dexter-mediated triplet energy transfer and the fundamental parameters controlling this process. Then we summarize current experimental methods used to measure the triplet exciton diffusion length. Finally, the use of hierarchically ordered structures to improve the triplet diffusion length is presented, before concluding with an outlook on the remaining challenges.

show abstract

“…However, the crystalline systems have suffered from the aggregation of donor molecules and their segregation in acceptor crystals, which caused poor TET efficiency. 4 Despite efforts to solve this problem, 28,29,[32][33][34] the development of a simple and rational strategy to molecularly accommodate donor molecules in acceptor crystals is still anticipated.…”

Section: Introductionmentioning

confidence: 99%

“…In this perspective, it is natural to develop triplet energy migration-based photon upconversion (TEM-UC), 10 in which triplet excitons effectively diffuse in densely organized molecular assemblies without molecular diffusion. [21][22][23][24][25][26][27][28][29][30][31][32] Among various assembly systems, molecular crystals with ordered chromophore arrangements should be promising for achieving fast TEM. However, the crystalline systems have suffered from the aggregation of donor molecules and their segregation in acceptor crystals, which caused poor TET efficiency.…”

Section: Introductionmentioning

confidence: 99%

Kinetically controlled crystal growth approach to enhance triplet energy migration-based photon upconversion

et al. 2017

View full text Add to dashboard Cite

Nobuo Kimizuka, "Kinetically controlled crystal growth approach to enhance triplet energy migration-based photon upconversion," J. Photon. Energy 8(2), 022003 (2017), doi: 10.1117/1.JPE.8.022003. Abstract. Improving efficiency of triplet-triplet annihilation-based photon upconversion (TTA-UC) in crystalline media is challenging because it usually suffers from the severe aggregation of the donor (sensitizer) molecules in acceptor (emitter) crystals. We show a kinetically controlled crystal growth approach to improve donor dispersibility in acceptor crystals. As the donor-acceptor combination, a benchmark pair of platinum(II) octaethylporphyrin (PtOEP) and 9,10-diphenylanthracene (DPA) is employed. A surfactant-assisted reprecipitation technique is employed, where the concentration of the injected PtOEP-DPA solution holds the key to control dispersibility; at a higher PtOEP-DPA concentration, a rapid crystal growth results in better dispersibility of PtOEP molecules in DPA crystals. The improvement of donor dispersibility significantly enhances the TTA-UC quantum yield. Thus, the inherent function of donor-doped acceptor crystals can be maximized by controlling the crystallization kinetics.

show abstract

Photon Upconversion at Crystalline Organic–Organic Heterojunctions

Cited by 134 publications

References 24 publications

Surface‐Mounted Metal–Organic Frameworks: Crystalline and Porous Molecular Assemblies for Fundamental Insights and Advanced Applications

Surface‐Mounted Metal–Organic Frameworks: Crystalline and Porous Molecular Assemblies for Fundamental Insights and Advanced Applications

Triplet transport in thin films: fundamentals and applications

Kinetically controlled crystal growth approach to enhance triplet energy migration-based photon upconversion

Contact Info

Product

Resources

About