This is the first report on a plasma enhanced spatial atomic layer deposition (APP-ALD) process at atmospheric pressure to grow conducting metallic Cu thin films from a carbene stabilized precursor.

The unique properties of atomic layer deposition (ALD) are mainly exploited for metal oxides, while the growth of metals, such as silver, is still in its infancy. Low growth temperatures and high growth rates are essential to achieve conductive (i.e. percolated) films. Here, a study based on the authors’ recently introduced N‐heterocyclic carbene‐based Ag amide precursor [(NHC)Ag(hmds)] (1,3‐di‐tert‐butyl‐imidazolin‐2‐ylidene silver(I) 1,1,1‐trimethyl‐N‐(trimethylsilyl) silanaminide) using plasma‐enhanced spatial ALD at atmospheric pressure and at deposition temperatures as low as 60 °C, is provided. The favorable reactivity and high volatility of the [(NHC)Ag(hmds)] precursor affords high growth rates up to 3.4 × 1014 Ag atoms cm–2 per cycle, which are ≈2.5 times higher than that found with the established triethylphosphine(6,6,7,7,8,8,8‐heptafluoro‐2,2‐dimethyl‐3,5‐octanedionate) silver(I) [Ag(fod)(PEt3)] precursor. Consequently, highly conductive Ag films with resistivities as low as 2.7 µΩ cm are achieved at a deposition temperature of 100 °C with a percolation threshold of ≈2.6 × 1017 Ag atoms cm–2, which is more than 1.6 times lower compared to [Ag(fod)(PEt3)]. As a concept study, conductive Ag layers are used as bottom electrodes in organic solar cells, that achieve the same performance as those based on Ag electrodes resulting from a high vacuum process.

A fully soluble poly(9,10-anthrylene ethynylene), poly[2,6-(2-octyldecyl)-9,10-anthrylene ethynylene] PAAE, with moderate degrees of polymerization Pn of ca. 10 is generated in a reductive, dehalogenative homocoupling scheme, starting from a 2,6-dialkylated 9,10-bis(dibromomethylene)-9,10-dihydroanthracene monomer and n-BuLi/CuCN as reducing agent. PAAE shows surprisingly broad and unstructured absorption and photoluminescence emission bands peaking at 506 nm and 611 nm, respectively, both in chloroform solution. The long absorption tail ranging into the 600-700 nm region and the large Stokes shift point to a high degree of geometrical disorder in the arrangement of the 9,10-anthrylene chromophores along the distorted polymer backbone. This disorder is borne out in the unusually strong wavelength dependence of fluorescence depolarisation, both with regards to the excitation and the emission wavelengths. Picosecond fluorescence depolarisation spectroscopy provides clear evidence for the presence of orthogonal transition dipole moments, presumably arising from the off-axis transition of the anthracene unit and the on-axis transition of the polymer backbone.