Optical Properties and Light-Induced Charge Transfer in Selected Aromatic C60 Fullerene Derivatives and in Their Bulk Heterojunctions with Poly(3-Hexylthiophene)

Abstract

Fullerene derivatives offer great scope for modification of the basic molecule, often called a buckyball. In recent years, they have been the subject of numerous studies, in particular in terms of their applications, including in solar cells. Here, the properties of four recently synthesized fullerene C60 derivatives were examined regarding their optical properties and the efficiency of the charge transfer process, both in fullerene derivatives themselves and in their heterojunctions with poly (3-hexylthiophene). Optical absorption, electron spin resonance (ESR), and time-resolved photoluminescence (TRPL) techniques were applied to study the synthesized molecules. It was shown that the absorption processes in fullerene derivatives are dominated by absorption of the fullerene cage and do not significantly depend on the type of the derivative. It was also found by ESR and TRPL studies that asymmetrical, dipole-like derivatives exhibit stronger light-induced charge transfer properties than their symmetrical counterparts. The observed inhomogeneous broadening of the ESR lines indicated a large disorder of all polymer–fullerene derivative blends. The density functional theory was applied to explain the results of the optical absorption experiments.

Impact of the aliphatic side chain length on photovoltaic properties of fullerenes functionalized with 3-(1-indenyl)propionic acid esters

“…For the PC 60 BM reference material, we observed absorption gradually rising from 1.2 eV to a single maximum at 3.6 eV. 33–35 The absorbance peak results from S 0 → S 2 and S 0 → S 3 . The lower energy transition S 0 → T 1 is forbidden due to high symmetry of C 60 fullerene.…”

Enhanced luminescence sensing performance and increased intrachain order in blended films of P3HT and cellulose nanocrystals

“…However, such an investigation while an interesting research endeavour, is beyond the scope of the present work. In a bulk heterojunction organic solar cell, an organic donor polymer such as P3HT is mixed with an appropriate acceptor such as C 60 and its derivatives [46,51].…”

Simple and effective in situ sample illumination for electron paramagnetic resonance

“…Paramagnetic species under continuous illumination can be recorded at steady state, such experiments have been reported with xenon lamps, 10–14 solar simulators, 10 lasers, 15–18 or LEDs. 13,19–22…”

“…Paramagnetic species under continuous illumination can be recorded at steady state, such experiments have been reported with xenon lamps, [10][11][12][13][14] solar simulators, 10 lasers, [15][16][17][18] or LEDs. 13,[19][20][21][22] Providing sufficient optical access to the sample within the EPR resonator for in situ illumination can be challenging. Direct illumination through the optical window of a resonator gives a straight-forward light path.…”