Effect of porosity and heat treatment of TiO2 on the electrochromic properties of poly(3-hexylthiophene-2,5-diyl) (P3HT)-TiO2 composites
Por:
Baray-Calderon, A, Camacho-Cáceres, J, Gomez-Cortez, A, Hu, HL, Nicho, ME
Publicada:
15 feb 2026
Resumen:
Single poly(3-hexylthiophene-2,5-diyl) (P3HT) layer based electrochromic devices (ECDs) usually show less optical contrast (Delta T%) and slow color change speeds. In this work, by introducing mesoporous titanium dioxide (m-TiO2) as substrate layers of P3HT, the two electrochromic (EC) parameters have been improved in P3HT based ECDs. To obtain m-TiO2 of different porosity, poly(vinylpyrrolidone) (PVP) has been included as a sacrificial agent in titanium precursor solutions in two different quantities. Then the solutions are deposited by spin coating on fluorine-doped tin oxide (FTO) coated glass substrates, followed by a thermal annealing at 450 and 500 degrees C. After that, a P3HT solution is deposited on top of m-TiO2 by spin coating to obtain TiO2:P3HT composites. Scanning electron microscopy (SEM) analysis reveals that the surface porosity of the TiO2 layers, ranging from approximately 12 %-14 %, is congruent with the amount of PVP used in the precursor solutions, with sponge-like and granular morphologies for the samples annealed at 450 and 500 degrees C, respectively. Cyclic voltammetry (CV) curves of the EC layers show higher cyclic stability for 450 degrees C annealed samples. The incorporation of TiO2 layers increases the maximum Delta T% values of P3HT based ECDs from 17.3 % to 25 %, and reduces the bleaching time of the same devices from 26.60 s to 23.84 s in the best composite. This improvement comes from a larger contact area between m-TiO2 substrates and P3HT, and consequently a larger interface area between P3HT and the electrolyte in the ECDs to achieve a larger ion intercalation.
Filiaciones:
Univ Autonoma Estado Morelos, Ctr Invest Ingn & Ciencias Aplicadas, Cuernavaca 62209, Morelos, Mexico
Univ Nacl Autonoma Mexico, Inst Energias Renovables, Temixco 62580, Morelos, Mexico
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