Electrogenerated chemiluminescence of Ge nanocrystals

Organic layer capped Ge nanocrystals (NCs) were synthesized by an arrested-growth method within supercritical octanol. Electrogenerated chemiluminescence (ECL) from the Ge NCs dispersed in N,N'-dimethylformamide (DMF) containing 0.1 M tetra-n-butylammonium perchlorate (TBAP) was observed during potential scans or pulses through the annihilation of electrogenerated oxidized and reduced species. The light emission intensity was higher during the oxidation scans and pulses, suggesting that the reduced forms were more stable than the oxidized ones. The ECL spectrum was obtained by potential stepping between the potentials for oxidation and reduction. The ECL spectrum was red-shifted from the photoluminescence spectrum by similar to200 nm, which implied, in agreement with previous studies, ECL emission predominantly via surface states and the importance of the surface passivation on ECL.