Ambience-related adsorbates on CuPc surface—Photoemission and thermal desorption spectroscopy studies for control of organic electronics degradation processes

• Air-induced chemical structure alteration of 32 nm-CuPc studied by ARXPS
• UPS, PYS probed electronic parameters changes due to gas interaction
• TDS quantification of CuPc adsorbates’ activation energies for desorption

In present work, using the angle-resolved X-ray photoelectron spectroscopy, the chemical structure of the 32 nm-thick copper phthalocyanine (CuPc) films surface was revealed upon long-term ambient air exposure. The existence of ambience-related components was detected in the C1s, N1s and O1s spectra and their depth distributions within the CuPc layer were analyzed. Combined ultraviolet photoelectron and photoemission yield spectroscopies provided information concerning redistribution of electron density in surface region which was reflected in surface band bending increase by 0.91 eV, shift in electron affinity of 0.26 eV and work function variation of 1.17 eV. The kind and amount of desorbed molecules or atoms from phthalocyanine’s surface were investigated by the thermal desorption spectroscopy. Quantified activation energies for desorption of C, N2, O2 and H2O species with values in the range of 120–166 kJ/mol indicated chemical adsorption process (of rather covalent than ionic nature) of the ambience related adsorbates on organic surface.