In Situ Electroluminescence Color Tuning by Thermal Deprotonation Suitable for Thermal Sensors and Anti-fraud Labels

A novel and versatile approach to tune photoluminescence
and electroluminescence by in situ controlled thermal deprotonation
is presented. This methodology, based on a single organic
p-conjugated material (pyrene derivative), allows the
manufacturing of organic light-emitting diode (OLED) prototypes
by solution methods with controlled tunable emission
ranging from the orange (protonated form of the dye) to the
blue (pristine or deprotonated form). While several protonation/
deprotonation cycles can be performed on thin films, for
the devices only one cycle is possible so that their use as antifraud
labels can be envisaged. OLEDs exhibit daylight visible
brightness of 150 cdm-2 and device lifetime exceeding 30
hours of continuous operation. Thanks to the simplicity of
both material design and device fabrication our approach
opens new perspectives in the wide field of thermal sensors
for customer care or risk perception.