Light-emitting electrochemical cells, featuring uniform and efficient light emission over areas of 200 cm(2) , are fabricated under ambient air with a for-the-purpose developed "spray-sintering" process. This fault-tolerant fabrication technique can also produce multicolored emission patterns via sequential deposition of different inks based on identical solvents. Significantly, additive spray-sintering using a mobile airbrush allows a straightforward addition of emissive function onto a wide variety of complex-shaped surfaces, as exemplified by the realization of a light-emitting kitchenware fork.

Ludvig Edman and co‐workers report that the efficiency of the photochemical monomer‐to‐dimer transformation of the fullerene [6,6′]‐phenyl‐C61‐butyric acid methyl ester (PCBM) is strongly dependent on the light intensity. This information is used to demonstrate that direct patterning of electronically active PCBM films can be effectuated by subsecond UV‐light exposure. It is demonstrated that the fullerene dimer formation must constitute a bi‐excited reaction between two neighboring monomers photoexcited to the triplet state.

Experimental fi ndings and associated theoretical insights regarding the photochemical transformation of fullerenes are reported, which challenge the conventional wisdom in the fi eld and point out a viable path towards improved fullerene-based electronic devices. It is shown that the effi ciency of the photochemical monomer-to-dimer transformation of the fullerene [6,6 ′ ]-phenyl-C 61 -butyric acid methyl ester (PCBM) is strongly dependent on the light intensity, and this is utilized to demonstrate that direct patterning of an electroactive PCBM fi lm can be effectuated by sub-second UV-light exposure followed by development in a tuned developer solution. By straightforward analytical reasoning, it is demonstrated that the observed intensitydependent monomer-to-dimer transformation dictates that a signifi cant back-reaction to the ground state must be in effect, which presumably originates from the excited-triplet state. By a combination of numerical modeling and analytical argumentation, it is further shown that the fi nal dimer formation must constitute a bi-excited reaction between two neighboring monomers photo-excited to the triplet state.

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We present a laser interference patterning method for the facile fabrication of large-area and high-contrast arrays of semiconducting fullerene nanostructures, which does not rely on a tedious application of sacrificial photoresists or photomasks. A solution-deposited phenyl-C-butyric acid methyl ester (PCBM) fullerene thin film is exposed to a spatially modulated illumination intensity, as realized by a two-beam laser interference. The PCBM molecules exposed to strong intensity are photochemically transformed into a low-solubility dimeric state, so that the nontransformed PCBM molecules can be selectively removed in a subsequent solution-based development step. Following brief exposure to green laser light (λ = 532 nm, t = 5 s, p = 0.17 W cm) in the designed two-beam interference setup, and a 1 min development in a tuned acetone-chloroform solution, we realize well-defined and ordered PCBM nanostripe patterns with a fwhm line width of ∼200 nm and a repetition rate of ∼2.900 lines mm over a large area of 1 cm. We demonstrate that a desired high contrast is effectuated because the initial PCBM-dimer transformation rate is dependent on the square of the illumination intensity. The semiconducting functionality of the patterned fullerene is verified in a field-effect transistor experiment, where a typical PCBM nanostripe featured an electron mobility of 5.3 × 10 cm V s and an on/off ratio of 3 × 10.