Absorption and crystallinity of poly(3-hexylthiophene)/fullerene blends in dependence on annealing temperature

Erb, Tobias; Zhokhavets, Uladzimir; Hoppe, Harald; Gobsch, G.; Al‐Ibrahim, Maher; Ambacher, O.

doi:10.1016/j.tsf.2005.12.064

Cited by 68 publications

(46 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Increases in optical absorption after annealing have been observed for P3HT and are found to derive from aggregation/interchain interactions and an increase in the crystallinity of the material, which enhances the probability of optically active p-p Ã electronic transitions. [33][34][35] www.afm-journal.de An increase in the crystallinity of annealed DPP(TBFu) 2 was also confirmed by X-ray diffraction (XRD) studies (Supporting Information, Fig. S1).…”

Section: Introductionmentioning

confidence: 57%

Nanoscale Phase Separation and High Photovoltaic Efficiency in Solution‐Processed, Small‐Molecule Bulk Heterojunction Solar Cells

Walker

Tamayo

Dang

et al. 2009

Adv Funct Materials

888

822

View full text Add to dashboard Cite

Research relating to organic solar cells based on solution‐processed, bulk heterojunction (BHJ) films has been dominated by polymeric donor materials, as they typically have better film‐forming characteristics and film morphology than their small‐molecule counterparts. Despite these morphological advantages, semiconducting polymers suffer from synthetic reproducibility and difficult purification procedures, which hinder their commercial viability. Here, a non‐polymeric, diketopyrrolopyrrole‐based donor material that can be solution processed with a fullerene acceptor to produce good quality films is reported. Thermal annealing leads to suitable phase separation and material distribution so that highly effective BHJ morphologies are obtained. The frontier orbitals of the material are well aligned with those of the fullerene acceptor, allowing efficient electron transfer and suitable open‐circuit voltages, leading to power conversion efficiencies of 4.4 ± 0.4% under AM1.5G illumination (100 mW cm−2). Small molecules can therefore be solution processed to form high‐quality BHJ films, which may be used for low‐cost, flexible organic solar cells.

show abstract

Section: Introductionmentioning

confidence: 57%

Nanoscale Phase Separation and High Photovoltaic Efficiency in Solution‐Processed, Small‐Molecule Bulk Heterojunction Solar Cells

Walker

Tamayo

Dang

et al. 2009

Adv Funct Materials

888

822

View full text Add to dashboard Cite

show abstract

“…Interestingly, the observed increase in optical absorption in the range of 1.9 to 3.0 eV upon annealing is directly correlated to the crystallization-induced ordering of P3HT in these blends (see with Fig. 36) [182].…”

Section: Polymer-fullerene Solar Cellsmentioning

confidence: 77%

Polymer Solar Cells

Hoppe

Sariciftci

2007

Photoresponsive Polymers II

Self Cite

124

121

View full text Add to dashboard Cite

“…6c). The observed coloured halos around the needles are attributed to the light interference originating from the changes in the film thickness, and is due to the PCBM-depleted regions [38,39]. Despite the difference in the density of crystals formed, the individual crystals are of similar shape.…”

Section: Polarized Optical Microscopymentioning

confidence: 98%

Comparative study: the effect of annealing conditions on the properties of P3HT:PCBM blends

et al. 2012

View full text Add to dashboard Cite

This paper presents a detailed study on the role of various annealing treatments on organic poly(3-hexylthiophene) and [6]-phenyl-C 61 -butyric acid methyl ester blends under different experimental conditions. A combination of analytical tools is used to study the alteration of the phase separation, structure and photovoltaic properties of the P3HT:PCBM blend during the annealing process. Results showed that the thermal annealing yields PCBM ''needle-like'' crystals and that prolonged heat treatment leads to extensive phase separation, as demonstrated by the growth in the size and quantity of PCBM crystals. The substrate annealing method demonstrated an optimal morphology by eradicating and suppressing the formation of fullerene clusters across the film, resulting in longer P3HT fibrils with smaller diameter. Improved optical constants, PL quenching and a decrease in the P3HT optical bad-gap were demonstrated for the substrate annealed films due to the limited diffusion of the PCBM molecules. An effective strategy for determining an optimized morphology through substrate annealing treatment is therefore revealed for improved device efficiency. IntroductionOrganic photovoltaic (OPV) solar cells have attracted significant attention due to their great potential for large-area, light-weight, flexible, and low-cost devices [1][2][3][4]. Recently, OPV research has been dominated by the poly(3-hexylthiophene):[6]-phenyl C 61 -butyric acid methyl ester (P3HT: PCBM) blend reaching power conversion efficiencies (PCEs) of 5-7 % [5,6]. Most recently a record PCE of about 8.13 and 8.5 % has been reported [7, 8]. Despite recent achievements, improvement in PCEs, stability and lifetime of the devices are necessary before organic solar cells become commercially viable [9][10][11]. The PCE of the solar cells based on the P3HT/fullerene system depends strongly on the processing conditions [12] and can be improved by increasing the crystalline content of the P3HT. Different approaches have been suggested for the optimization of the morphology, such as thermal annealing [5,6,[13][14][15]

show abstract

Absorption and crystallinity of poly(3-hexylthiophene)/fullerene blends in dependence on annealing temperature

Cited by 68 publications

References 13 publications

Nanoscale Phase Separation and High Photovoltaic Efficiency in Solution‐Processed, Small‐Molecule Bulk Heterojunction Solar Cells

Nanoscale Phase Separation and High Photovoltaic Efficiency in Solution‐Processed, Small‐Molecule Bulk Heterojunction Solar Cells

Polymer Solar Cells

Comparative study: the effect of annealing conditions on the properties of P3HT:PCBM blends

Contact Info

Product

Resources

About