Efficient Bulk Heterojunction Photovoltaic Cells using Sublimable Transition Metal Complex as Photosensitizers
- PDF / 58,276 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 4 Downloads / 193 Views
L5.19.1
Efficient Bulk Heterojunction Photovoltaic Cells using Sublimable Transition Metal Complex as Photosensitizers Hei Ling Wong1, Kitty Ka Yan Man1, Wai Kin Chan1*, Chung Yin Kwong2, Aleksandra B. Djurišić3 1 Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong 2 Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong 3 Department of Physics, The University of Hong Kong, Pokfulam Road, Hong Kong ABSTRACT Multilayer bulk heterojunction photovoltaic cells using chlorotricarbonyl rhenium (I) bis(phenylimino)acenaphthene (Re-DIAN) complex as photosensitizer were studied. The complex is sublimable, has lower band gap, good thermal stability and good processibility. It has broad absorption in UV-visible region. Therefore, Re-DIAN exhibits good photosensitising property for photovoltaic cells. Multilayer bulk heterojunction photovoltaic cells with simple structures were fabricated base on Re-DIAN complex. The active layer consists of a blend of ReDIAN and fullerene that were co-deposited in the same layer by vacuum deposition. The photovoltaic properties of the devices were studied by irradiaton under AM1.5 simulated solar light. The effects of changing the co-deposition film thickness, amount of Re-DIAN photosensitizer, and hole transporting materials were studied.
INTRODUCTION Many scientists are increasingly interested in high power and efficient solar cells based on both small organic molecules and conjugated polymers. It is because of the advantages of organic materials such as low fabrication costs, lightweight, tunability of the electronic band gap by chemical synthesis, and simple fabrication into flexible and thin film panels. However, many studies showed that organic solar cells in general exhibit much lower efficiencies of energy conversion compared to current inorganic silicon solar cells. One of the major barriers to fabricate efficient organic photovoltaic cells is the insufficient exciton dissociation at low bias and the low charge carrier mobility. In order to design an efficient organic photovoltaic cell, the efficiency for dissociation of excitons and the charge transport process should be improved. A typical organic photovoltaic device consists of multilayer organic thin films. The photovoltaic performances in multilayer bulk heterojunction devices can be greatly improved compared to that in multilayer heterojunction devices [1]. The bulk heterojunction consists of a blend of two materials, which form interpenetrating networks that one of the materials serve as the electron donor and the other one serve as the electron acceptor. After Re-DIAN is excited, it transfers an electron to C60 immediately so that a pair of free hole and electron is generated. Then, these charges are transported to the corresponding electrodes, which results in the generation of photocurrent.
L5.19.2
EXPERIMENTAL DETAILS Synthesis of photosensitizer Chlorotricarbonyl rhenium (I) bis(phenylimino)acenaphthene (Re-DIAN) complex [2] was used as the
Data Loading...
