resumo
Poly(fluorene) conjugated polyelectrolyte (CPE)-di-ureasil organic-inorganic composites have been prepared using a versatile sol-gel processing method, which enables selective localisation of the CPE within the di-ureasil matrix. Introduction of the CPE during the sol-gel reaction leads to a homogeneous distribution of the CPE throughout the di-ureasil, whereas a post-synthesis solvent permeation route leads to the formation of a confined layer of the CPE at the di-ureasil surface. The CPE and the di-ureasil both function as photoactive components, contributing directly to, and enhancing the optical properties of their composite material. The bright blue photoluminescence exhibited by CPE-di-ureasils is reminiscent of the parent CPE; however the distinct contribution of the di-ureasil to the steady-state emission profile is also apparent. This is accompanied by a dramatic increase in the photoluminescence quantum yield to >50%, which is a direct consequence of the synergy between the two components. Picosecond time-correlated single photon counting measurements reveal that the di-ureasil effectively isolates the CPE chains, leading to emissive trap sites which have a high radiative probability. Moreover, intimate mixing of the CPE and the di-ureasil, coupled with their strong spectral overlap, results in efficient excitation energy transfer from the di-ureasil to these emissive traps. Given the simple, solution-based fabrication method and the structural tunability of the two components, this approach presents an efficient route to highly desirable CPE-hybrid materials whose optoelectronic properties may be enhanced and tailored for a targeted application.
palavras-chave
LIGHT-EMITTING-DIODES; PHOTO-CROSS-LINKING; ENERGY-TRANSFER; QUANTUM YIELDS; ORGANIC/INORGANIC HYBRIDS; SEMICONDUCTING POLYMER; HIGHLY EFFICIENT; RECENT PROGRESS; SILICA MATRIX; SOLAR-CELLS
categoria
Chemistry
autores
Willis-Fox, N; Marques, AT; Arlt, J; Scherf, U; Carlos, LD; Burrows, HD; Evans, RC
nossos autores
Luís Carlos
Professor CatedráticoProjectos
agradecimentos
The authors thank Prof. Rute A. S. Ferreira for thoughtful insight into the discussion of the results presented. This work was supported in part by the Science Foundation Ireland under Grant No. 12/IP/1608. NWF thanks the Irish Research Council for a Government of Ireland postgraduate studentship. The authors acknowledge financial support from the European Commission under the Seventh Framework Programme by means of the grant agreement for the Integrated Infrastructure Initiative No. 262348 European Soft Matter Infrastructure (ESMI). Support from COST action MP1202 (HINT - Hybrid Interfaces) is also gratefully acknowledged. Solid-state NMR spectra were obtained at the EPSRC UK National Solid-state NMR Service at Durham. HDB thanks the Coimbra Chemistry Centre for support from the Fundacao para a Ciencia e a Tecnologia (FCT), Portuguese Agency for Scientific Research, through the project PEst-OE/QUI/UI0313/2014. This work was partially developed in the scope of the project CICECO-Aveiro Institute of Materials (Ref. FCT UID/CTM/50011/2013), financed by Portuguese funds through the FCT/MEC and when applicable co-financed by FEDER under the PT2020 Partnership Agreement.