Self‐Powered Flexible TiO₂ Fibrous Photodetectors: Heterojunction with P3HT and Boosted Responsivity and Selectivity by Au Nanoparticles

Abstract

A novel inorganic–organic heterojunction (TiO2/P3HT (poly(3‐hexylthiophene)) is easily prepared by a combination of anodization and vacuumed dip‐coating methods, and the constructed flexible fibrous photodetector (FPD) exhibits high‐performance self‐powered UV–visible broadband photoresponse with fast speed, high responsivity, and good stability, as well as highly stable performance at bending states, showing great potential for wearable electronic devices. Moreover, Au nanoparticles are deposited to further boost the responsivity and selectivity by regulating the sputtering intervals. The optimal Au/TiO2/P3HT FPD yields an ≈700% responsivity enhancement at 0 V under 350 nm illumination. The sharp cut‐off edge and high UV–visible rejection ratio (≈17 times higher) indicate a self‐powered flexible UV photodetector. This work provides an effective and versatile route to modulate the photoelectric performance of flexible electronic devices.

Dramatic Responsivity Enhancement Through Concentrated H2SO4 Treatment on PEDOT:PSS/TiO2 Heterojunction Fibrous Photodetectors

“…The weak absorption in the visible light region (400–800 nm) of TiO 2 is originated from the light scattering effect caused by pores/cracks in the NTs. [ 25 ] The enhanced visible light absorption of PEDOT:PSS/TiO 2 and PEDOT:PSS is associated with the free charge carriers in PEDOT. While the strong absorption in the UV region for PEDOT:PSS is ascribed to the phenyl moieties in PSS component (Figure S11b, Supporting Information).…”

“…The responsivity reaches 161 mA W −1 at 0 V under 365 nm illumination (Figure 6d), outperforming most of the recently reposted fibrous PDs in literature (Table S1, Supporting Information). [ 24,25 ] By comparison, H‐PEDOT:PSS/TiO 2 FPD device displays dramatically enhanced responsivity at 0 V bias: is ≈32 times higher than that of PEDOT:PSS/TiO 2 FPD at 0 V (i.e., enhancement of 3200%, Figure 6e). The D * of the FPD obtained using Equation () is 8.87 × 10 10 Jones (Figure 6f) under 365 nm irradiation, which is 3.3 times higher than that of the untreated FPD counterpart ( D * = 2.61 × 10 10 Jones).…”

“…Synthesis of PEDOT:PSS/TiO 2 Hybrid: The loading of PEDOT:PSS organic polymer was followed a vacuum impregnation method from our previous report. [25] The synthesized TiO 2 NTs fiber was placed in a bottle which was sealed to pump vacuum for 2 h. PEDOT:PSS (ORGACIN Dry, AGFA) dispersed in ethyl alcohol with a concentration of 5 mg mL −1 was injected and remained in vacuum for another 2 h. The PEDOT:PSS/TiO 2 hybrid was obtained after washing with ethanol and drying at 120 °C for 15 min for a better interface.…”

“…A novel self‐powered Au/TiO 2 /P3HT FPD with a responsivity enhancement of nearly 700% compared with the TiO 2 /P3HT counterpart device has been reported. [ 25 ] Given the crooked and tiny irradiated area of photoactive materials, it is still a big challenge to yield considerable photoresponse (responsivity, photocurrent, sensitivity) on FPDs. Moreover, it is also imperative to explore novel and effective heterojunction via a facile and economic route and thereby enabling high‐performance self‐powered FPDs.…”

Numerical study of a highly efficient light trapping nanostructure of perovskite solar cell on a textured silicon substrate

“…In light trapping structures, due to a shift in the direction of light path within the active layer, its interaction time with this layer increases, which increases the optical absorption 21 – 24 . In these structures, by scattering the light to the off-normal directions, in addition to prolonging its pathlength in the active layer, the probability of reflection of each interface increases due to its angular movement.…”