Organic-inorganic Hybrid Photovoltaic Devices With Bilayer Heterojunction, Bulk Heterojunction, And Ordered Nanoarray Heterojunction Structures

For the growing energy demand of human, the research about solar energy has attracted more and more attention and support. Because of its high photoelectric conversion efficiency, inorganic solar cells become the mainstay of market. And organic polymer solar cells get much more attention because of its low production cost and simple production process. However, the organic-inorganic composite solar cells can be combined with their respective advantages. This paper mainly researches some key issues around preparation and mechanism of the organic-inorganic composite material photovoltaic devices, which are organic-inorganic hybrid bilayer heteroj unction, bulk heteroj unction and ordered bulk heteroj unction photovoltaic devices.(1) Amorphous silicon combined with polymer P3HT (Poly(3-hexylthiophene-2,5-diyl)) as the research object for organic-inorganic composite bilayer heterojunction solar cells.1) Successfully deposited the amorphous intrinsic silicon, P-type silicon, N-type silicon thin film with radio frequency plasma enhancement chemical vapor deposition (RF-PECVD), and measured the absorption spectrum, refractive index, and optical band gap; 2) Deposited amorphous silicon on the surface of polymer P3HT to form P3HT/a-Si:H hybrid structure; and identified its film quality by optical microscopy and infrared spectroscopy; 3) Constructed P3HT/a-Si:H hybrid bilayer heterojunction photovoltaic device, and analyzed mechanisms which influence exciton dissociation, short-circuit current, open circuit voltage of such devices. According to the analysis it is necessary to use bulk heterojunction structure to improve the efficiency of photovoltaic devices.(2) The carbon black nanoparticles were composited with P3HT to study organic-inorganic hybrid bulk heterojunction photovoltaic device performance.1) basic structure of carbon black nanoparticles were identified with SEM and XRD, then followed by solubility experiments, and selecting a suitable surfactant material to improve solubility; 2) The nanoparticle was modified by grafting with flexible alkyl-groups onto nanoparticle surface to further improve its solubility and doesn’t change its basic characteristics; 3) The modified carbon black nanoparticles were doped into polymer:fullerene bulk heterojunction photovoltaic device, so that the hole mobility of active layer is increased by one order of magnitude, thus inorganic nanoparticles have a positive effect to improve the performance of photovoltaic devices.(3) TiO2 ordered nanotube array was synthesized and combined with P3HT, tb-CuPc (Copper(Ⅱ) 2,9,16,23-tetratertbutyl-29H,31H-phthalocyanine), and tm-Peryleneate (tetramethyl perylene-3,4,9,10-tetra-carboxylate) to making organic-inorganic hybrid ordered bulk heteroj unction structure.1) Systematically investigated various factors of titania nanotube growth process using two electrodes anodic oxidation; 2) P3HT is poured into the suitable size TiO2 nanotubes to prepare hybrid ordered heteroj unction photovoltaic device, so that the photoelectric conversion efficiency is improved by 32%; 3) The disk-shaped organic molecules tb-CuPc, tm-Peryleneate were combined with ordered TiO2 nanotube array. The edge-on (planar) discotic phase crystallization exhibited face-on (homeotropic) phase crystallization due to the induction of ordered nanotube array. This achievement provides a method to change the molecular orientation of disk-shaped molecules effectively.