School of Physics & Astronomy, University of St Andrews (USTAN)
The University of St Andrews (USTAN) is Scotland’s first University, well known for its research across the sciences and humanities. Its physics department was ranked third equal in REF 2014 (the most recent national measurement of research quality), and is well known for pioneering work on optoelectronics. It houses the Organic Semiconductor Centre which provides extensive facilities for the study of organic semiconductor materials and devices and collaborates with researchers in chemistry, biology and medicine. Since its establishment in 2001, the OSC has produced well over 300 refereed papers and more than 10 patents. It has expanded the range of organic semiconductor materials with light-emitting dendrimers, and the range of OLED applications with skin cancer treatment. The centre is internationally recognised for its expertise in organic semiconductor photophysics – particularly photoluminescence measurements.
- Optoelectronic device fabrication facility comprising a clean room with optical lithography tools, a glove box system with controlled atmosphere at 1 ppm of O2 and H2O for device encapsulation and characterisation.
- Hammatsu multifunctional probe station that includes an integrating sphere for optoelectronic device characterisation and absolute quantum yield measurements of electroluminescent devices and films at controlled temperature and environment.
- Edinburgh Instruments fluorescence spectral measurement and time correlated single photon counting system (TSPC) with PicoQuant diode lasers as excitation sources that cover the absorption spectrum of organic polymers. The detection is with a photomultiplier tube or a multichannel plate (MCP) which allow time resolutions of 500 ps and 200 ps respectively. By integrating a cryostat into the sample chamber, the system allows temperature controlled measurements from room temperature to 77 K.
- State-of-the-art facility of Femtosecond PHAROS laser system with tuneable oscillator over the visible range and an instrument response function of 30 fs. This is synchronised with a visible and infra-red Hammatsu Streak cameras that have a timing resolution of ~ 2ps (20 ps in the IR). Measurements can also be performed from room temperature to 77 K by integrating the Streak Camera with a cryostat.
Key personnel involved:
Prof. Samuel founded and leads the Organic Semiconductor Centre at the University of St Andrews. The centre brings together physicists and chemists to take an interdisciplinary approach to understanding these materials and devices made from them. A distinctive feature of these materials is that their excitons are strongly bound at room temperature. Current research includes the study of their photophysics, with particular emphasis on exciton diffusion, the development of new materials such as light-emitting dendrimers, and research on devices such as solar cells, light-emitting diodes and lasers. The work involves basic understanding of the materials, and relating it to the operation of devices.
Hedley, G. J., Ruseckas, A. & Samuel, I.D.W. 25 Jan 2017, Chemical Reviews. 117, 2, p. 796-837 42 p.
 Exciton diffusion length and charge extraction yield in organic bilayer solar cells
Siegmund, B., Sajjad, M. T., Widmer, J., Ray, D., Koerner, C., Riede, M., Leo, K., Samuel, I. D. W. & Vandewal, K. 28 Mar 2017 ,Advanced Materials. 29, 12, 5 p., 1604424
 Direct observation of intersystem crossing in a thermally activated delayed fluorescence copper complex in the solid state
Bergmann, L., Hedley, G. J., Baumann, T., Braese, S. & Samuel, I. D. W. 1 Jan 2016, Science Advances. 2, 1, e1500889
 The impact of driving force on electron transfer rates in photovoltaic donor-acceptor blends
Ward, A. J., Ruseckas, A., Kareem, M. M., Ebenhoch, B., Serrano, L. A., Al-Eid, M., Fitzpatrick, B., Rotello, V. M., Cooke, G. & Samuel, I. D. W. 17 Apr 2015, Advanced Materials. 27, 15, p. 2496–2500
 Fluorescent red-emitting BODIPY oligofluorene star-shaped molecules as a color converter material for visible light communications
Sajjad, M. T., Manousiadis, P. P., Orofino, C., Cortizo-Lacalle, D., Kanibolotsky, A. L., Rajbhandari, S., Amarasinghe, C. D. A., Chun, H., Faulkner, G., O'Brien, D. C., Skabara, P. J., Turnbull, G. A. & Samuel, I. D. W. Apr 2015, Advanced Optical Materials. 3, 4, p. 536-540 5 p.
 Wearable organic optoelectronic sensors for medicine
Bansal, A. K., Hou, S., Kulyk, O., Bowman, E. M. & Samuel, I. D. W. 2014, Advanced Materials.
 Determining the optimum morphology in high-performance polymer-fullerene organic photovoltaic cells
Hedley, G. J., Ward, A. J., Alekseev, A., Howells, C. T., Rezende Martins, E., Serrano, L. A., Cooke, G., Ruseckas, A. & Samuel, I. D. W. 17 Dec 2013, Nature Communications. 4, 10 p., 2867
Relevant projects/ activities:
 Participation in the LAMP Project
 EXCITON – ERC Advanced grant to study exciton diffusion