@article{HahnTscheuschnerSalleretal.2016, author = {Hahn, Tobias and Tscheuschner, Steffen and Saller, Christina and Strohriegl, Peter and Boregowda, Puttaraju and Mukhopadhyay, Tushita and Patil, Satish and Neher, Dieter and B{\"a}ssler, Heinz and K{\"o}hler, Anna}, title = {Role of Intrinsic Photogeneration in Single Layer and Bilayer Solar Cells with C-60 and PCBM}, series = {The journal of physical chemistry : C, Nanomaterials and interfaces}, volume = {120}, journal = {The journal of physical chemistry : C, Nanomaterials and interfaces}, publisher = {American Chemical Society}, address = {Washington}, issn = {1932-7447}, doi = {10.1021/acs.jpcc.6b08471}, pages = {25083 -- 25091}, year = {2016}, language = {en} } @article{ParkinsonAharonChangetal.2007, author = {Parkinson, P. and Aharon, E. and Chang, M. H. and Dosche, Carsten and Frey, G. L. and K{\"o}hler, Anna and Herz, L. M.}, title = {Dimensionality-dependent energy transfer in polymer-intercalated SnS2 nanocomposites}, doi = {10.1103/Physrevb.75.165206}, year = {2007}, abstract = {We have investigated the influence of dimensionality on the excitation-transfer dynamics in a conjugated polymer blend. Using time-resolved photoluminescence spectroscopy, we have measured the transfer transients for both a three-dimensional blend film and for quasi-two-dimensional monolayers formed through intercalation of the polymer blend between the crystal planes of an inorganic SnS2 matrix. We compare the experimental data with a simple, dimensionality- dependent model based on electronic coupling between electronic transition moments taken to be point dipoles. Within this approximation, the energy-transfer dynamics is found to adopt a three-dimensional character in the solid film and a two-dimensional nature in the monolayers present in the SnS2-polymer nanocomposite.}, language = {en} } @article{DeviAlSutiDoscheetal.2008, author = {Devi, Lekshmi Sudha and Al-Suti, Mohammed K. and Dosche, Carsten and Khan, Muhammad S. and Friend, Richard H. and K{\"o}hler, Anna}, title = {Triplet energy transfer in conjugated polymers : I. Experimental investigation of a weakly disordered compound}, year = {2008}, abstract = {Efficient triplet exciton emission has allowed improved operation of organic light-emitting diodes (LEDs). To enhance the device performance, it is necessary to understand what governs the motion of triplet excitons through the organic semiconductor. Here, we have investigated triplet diffusion using a model compound that has weak energetic disorder. The Dexter-type triplet energy transfer is found to be thermally activated down to a transition temperature T- T, below which the transfer rate is only weakly temperature dependent. We show that above the transition temperature, Dexter energy transfer can be described within the framework of Marcus theory. We suggest that below T-T, the nature of the transfer changes from phonon-assisted hopping to quantum-mechanical tunneling. The lower electron-phonon coupling and higher electronic coupling in the polymer compared to the monomer results in an enhanced triplet diffusion rate.}, language = {en} } @article{YangVardenyKoehleretal.2004, author = {Yang, C. and Vardeny, Z. V. and K{\"o}hler, Anna and Wohlgenannt, M. and Al-Suti, Mohammed K. and Khan, Muhammad S.}, title = {Spectroscopic study of spin-dependent exciton formation rates in pi-conjugated semiconductors : Comparison with electroluminescence techniques}, year = {2004}, abstract = {It has been found in recent measurements that the singlet-to-triplet exciton ratio in organic light-emitting diodes (OLEDs) is larger than expected from spin degeneracy, and that singlet excitons form at a larger rate than triplets. We employed the technique of optically detected magnetic resonance to measure the spin-dependent exciton formation rates in films of a polymer and corresponding monomer, and explore the relation between the formation rates and the actual singlet-to-triplet ratio measured previously in OLEDs. We found that the spin-dependent exciton formation rates can indeed quantitatively explain the observed exciton yields, and that singlet formation rates and yields are significantly enhanced only in polymer OLEDs, but not in OLEDs made from the corresponding monomer}, language = {en} } @article{MakHayerPascuetal.2005, author = {Mak, Chris S. K. and Hayer, Anna and Pascu, S. I. and Watkins, Scott E. and Holmes, Andrew B. and K{\"o}hler, Anna and Friend, Richard H.}, title = {Blue-to-green electrophosphorescence of iridium-based cyclometallated materials.}, issn = {0022-4936}, doi = {10.1039/b508695gb70}, year = {2005}, language = {en} } @article{KhanSreearunothaiHerzetal.2004, author = {Khan, Amena L. T. and Sreearunothai, Paiboon and Herz, Laura M. and Banach, Michael J. and K{\"o}hler, Anna}, title = {Morphology-dependent energy transfer within polyfluorene thin films}, year = {2004}, language = {en} } @article{HayerKoehlerArisietal.2004, author = {Hayer, Anna and K{\"o}hler, Anna and Arisi, E. and Bergenti, I. and Dediu, A. and Taliani, C. and Al-Suti, Mohammed K. and Khan, Muhammad S.}, title = {Polymer light-emitting diodes with spin-polarised charge injection.}, issn = {0379-6779}, year = {2004}, language = {en} } @article{KhanAlMandharyAlSutietal.2004, author = {Khan, Muhammad S. and Al-Mandhary, Muna R. A. and Al-Suti, Mohammed K. and Al-Battashi, Fathiya R. and Al-Saadi, Sultan and Bjernemose, Jens K. and Mahon, Mary F. and Chawdhury, Nazia and Yonus, Muhammad and K{\"o}hler, Anna and Teat, Simon J. and Marseglia, Elizabeth A. and Tedesco, Emilio and Feeder, Neil and Ahrens, Birte and Raithby, Paul R.}, title = {Synthesis, characterisation and optical spectroscopy of platinum(II) di-ynes and poly-ynes incorporating condensed aromatic spacers in the backbone}, issn = {1477-9226}, doi = {10.1039/B405070C}, year = {2004}, language = {en} } @article{SandeeWilliamsEvansetal.2004, author = {Sandee, A. J. and Williams, Charlotte K. and Evans, N. R. and Davies, J. E. and Boothby, C. E. and K{\"o}hler, Anna and Friend, Richard H. and Holmes, Andrew B.}, title = {Solution-processible conjugated electrophosphorescent polymers}, year = {2004}, language = {en} } @article{KoehlerBeljonne2004, author = {K{\"o}hler, Anna and Beljonne, David}, title = {The singlet-triplet exchange energy in conjugated polymers}, issn = {1616-3028}, year = {2004}, language = {en} }