利用TiO2纳米颗粒进行界面调控以增强基于P3HT的聚合物太阳能电池的介电和电荷传输性能

In this study, we present the effects of TiO 2 nanoparticle incorporation on the photovoltaic, dielectric, and structural properties of multilayer polymer solar cells (PSCs) based on poly(3-hexylthiophene) (P3HT). P3HT was merged with TiO 2 nanoparticles (< 25 nm) at various concentrations (0.0–10 wt%) and used as both interfacial modifiers and hole transport layers (HTLs). The optimized TiO 2 loading within the P3HT matrix improves interchain π–π stacking and crystallinity, resulting in enhanced charge delocalization and conductivity, as revealed by transmission electron microscope (TEM), x-ray diffraction (XRD), ultraviolet–visible (UV–Vis) spectroscopy, and broadband dielectric spectroscopy. Dielectric analyses reveal significant increases in permittivity and capacitance due to interfacial polarization and the formation of nanoscale capacitive domains. Impedance spectroscopy and AC conductivity studies reveal that TiO 2 doping enhances localized hopping transport and minimizes resistive losses. The direct current (DC) conductivity (σ dc ) increases from 2.02 × 10 –4 to 7.69 × 10 –4 S cm −1 . TiO 2 -doped HTLs in PSC devices achieve a power conversion efficiency (PCE) of 4.13% (17.45% increase in short-circuit current density (J sc )), surpassing the pristine device efficiency of 3.49%. The study reveals improvements in hole extraction and energy state alignment at the active layer/HTL interface, however, higher TiO 2 loading can cause structural disorder and performance decrease, suggesting a polymer photovoltaics interface engineering method for optimizing dielectric characteristics and charge transfer.