Poly(triarylamine)s- synthesis and application in electroluminescent devices and photovoltaics

Polymeric triphenyldiamines (p-TPD)s and naphthylphenyldiamines (p-NPD)s were synthesized by Ullmann reaction between bis(N,N-diaryl)amines and aryldiiodides in presence of phase-transfer catalyst, 18-crown-6. The polymers obtained are soluble in THF, CHCl3 etc and possess Tgs in the range of 206°C to 232°C and form stable and amorphous thin films. The HOMO energy values determined from cyclic voltammetry measurements lie between −5.10 and −5.17 eV with respect to vacuum energy level. The p-TPD and p-NPD are effectively applied as hole transport material in Electroluminescent devices, ITO/p-TPD/Alq3/Al. A solid-state solar cell, consisting of an inorganic nanocrystalline TiO2 layer coated on ITO for electron conduction, a surface-adsorbed ruthenium complex dye for light absorption and p-TPD as hole transport layer is also realized. Using appropriate counter electrode such as Au or Pt, quantum efficiencies of up to 0.2% and open circuit voltage of 550mV were realised.