document: Two different micro-contact set-ups were used in the experiments. The asymmetrically heated measurement set-up (Fig. 2a) allows to change the contacted electrode within seconds and thereby to gain statistical information over a large number of different microelectrodes on one and the same sample in a relatively short time. It also enables monitoring of optical changes during the measurement in real time. However, the asymmetrical heating from the bottom side and local cooling (e.g. by convection, radiation, and the contacting tip acting as a heat sink) is known to cause temperature gradients within the sample [11]. Such temperature gradients are responsible for thermo-voltages, which can lead to measurement artifacts in electrochemical experiments [24]. Moreover, in this set-up temperature cycles can hardly be performed on single microelectrodes but require subsequent contacting and de-contacting of different microelectrodes.
extractive_keyphrases: asymmetrical heating change the contacted electrode contacting tip convection electrochemical experiments gain statistical information heat sink local cooling microelectrodes monitoring of optical changes radiation temperature cycles temperature gradients
abstractive_keyphrases: asymmetrically heated measurement set-up contacting and de-contacting of different microelectrodes electrode micro-contact set-ups