Photoemission Studies on N-Substituted Dithienylated Phenothiazines

Dithienylated phenothiazines (DTPTs) with different functional groups attached to the central nitrogen atom are presented as a class of versatile metal‐free chromophores for the design of dye‐sensitized solar cells (DSSCs) and organic light‐emitting diodes (OLEDs). The electronic characteristics of spin‐coated thin films on polycrystalline gold were studied using photoelectron spectroscopy assisted by theoretical calculations, scanning force microscopy, and UV/Vis spectroscopy. Complementary fluorescence spectra show light emission in the blue region (465 nm). The absorption properties and good hole‐transporting abilities make DTPTs feasible hole‐transporting materials (HTM) and metal‐free chromophores in UV‐sensitive solar cell designs. UV‐sensitive molecules for organic photovoltaics: Six different phenothiazines with acceptor groups attached to the central nitrogen atom were symmetrically substituted with thiophene donor groups (see picture) and studied by using photoelectron spectroscopy and complementary methods. UV sensitivity and light emission in the blue region were observed. With a carboxylic group as the N‐substituent, the dithienylated phenothiazine can be utilized as a dye for TiO2‐based photovoltaics.