Dye Sensitization Of Flexible Solar Cells

As early as the 1970s, people hoped to develop new solar cells by simulating photosynthesis. At that time, people wrapped a layer of chlorophyll dye on the surface of semiconductor crystal material titanium dioxide (TiO2). Although the concept of dye sensitized solar cell (DSC) was proposed, due to the difficulty of electron transport in chlorophyll, the conversion efficiency was only 0.01%.
It was not until 1991 that Swiss chemist Michael Gratzel used nanotechnology to promote the substantive development of dye sensitized batteries. Gratzel replaces large particles of TiO2 crystals with small particles of spongy TiO2 with a diameter of 20 nm. The outer layer is coated with a thin layer of dye, forming a 10 um thick optical transparent film. The first dye sensitized battery made has achieved a conversion efficiency of 7.1% and a current density of 12 mA/cm ^ 2. Today, the world record for the conversion efficiency of dye sensitized batteries is 11%.
In the structure of a fuel sensitized cell, photosensitizers are coated on the surface of TiO2 particles through functional groups of carboxyl (- COOH), phosphoric acid (- PO3H2), or boric acid – B (OH) 2 to form a charge transfer complex. They are then immersed in a redox mediator solution, with TCO glass and metal substrates serving as cathodes and anodes, respectively. The photosensitizer absorbs emitted light, and the electrons in So in the ground state are excited to the high-energy state S *. Within fs to ps, the electrons in the photosensitizer enter the conduction band of TiO2. The photosensitizer loses electrons, is oxidized, and becomes S+. The redox mediator obtains electrons from the metal anode, and then provides electrons to the photosensitizer to reduce them. The free electrons on the conduction band of So. TiO2 return to the metal anode through the TCO cathode and circuit. A current is formed between the two electrodes to drive the load in the circuit.
Notes on Flexible Solar Cells
In March 2016, my scientist developed a new type of flexible solar cell, which experts believe is expected to be used to develop intelligent temperature controlled solar cells and wearable solar cells.