Interface Modification And Photovoltaic Performance Of Hybrid Solar Cells Based On P3HT And TiO₂Nanoarray

Solid-state organic-inorganic hybrid solar cells (HSCs) composed of conjugated conducting polymers (donors) and inorganic semiconductors (acceptors) in bulk hetero-junction (BHJ) structures have attracted considerable attention due to potential application to flexible, large-area, and low-cost photovoltaic devices. HSCs have been proposed to combine the advantages of high mobility, excellent chemical stability of metal oxides, and solution processability of polymers. In this thesis, the TiO2nanorod arrays and nanotube arrays have been prepared on the FTO substrate by hydrothermal method and anodization. The influence of process parameter on the morphology of the nanoarray has been investigated. Organic-inorganic hybrid solar cells have been fabricated, using the TiO2nanoarrays as the working electrode, the photoelectrical properties and interfacial modification mechanismhad have been studied. The main results are as follows:1. Preparation and morphology control of TiO2nanorod arrays. TiO2nanorod arrays have been prepared on the FTO substrate by a hydrothermal method. The influence of the Ti(OBu)4concentration, reaction temperature, reaction time and seed layer on the morphology of the nanorod arrays have been investigated. TiO2nanotube arrays have been fabricated by anodization using Ti film on the FTO. The NH4F concentration, applied voltage, reaction time and annealing temperature on the morphology and crystallization have been investigated.2. Preparation and interface modification of P3HT/TiO2nanorod arrays hybrid solar cells. HSCs based on P3HT and TiO2nanorod arrays have been fabricated. The quantum dots, organics and their composites were introduced as the interface modifiers. The influences of interface modification on the photoelectrical performance of HSCs were studied comprehensively. The results show that monolayer modifiers can accelerate carrier separation and reduce charge recombination at P3HT/TiO2interface. The efficiencies were increased to0.45%,0.94%and0.59%after pyridine, N719, CdSe modification, respectively. However, the performances of HSCs with composite interfacial modification were inferior to that with individual.3. Interface modification and improving the conductivity of P3HT in HSCs based on P3HT and TiO2nanotube arrays. We improved the peformance of HSCs with CdS and CdSe quantum dots as interface modifiers. The efficiencies were enhanced to0.42%and0.46%when suffered10deposition cycles, respectively. Furthermore, the introduction of graphene or carbon nanotubes to the P3HT also improved the cell performance compared to pristine P3HT, because graphene or carbon nanotubes can reduce the resistivity of P3HT and can serve as frameworks to accelerate charge transport.