Organic Solar Cell Phd Thesis An Assignment
This work presents new insights into the measurement of charge transport, the underlying physics, as well as new approaches for modelling.Numeric simulation software using a drift-diffusion-recombination model is developed and applied to organic photovoltaic devices.A conjugated system is formed where carbon atoms covalently bond with alternating single and double bonds.These hydrocarbons' electrons pz orbitals delocalize and form a delocalized bonding π orbital with a π* antibonding orbital.
charge extraction; charge transport; diffusion equations; fractional kinetics; high intensity RPV (HI- RPV); intensity dependent photocurrents (IPC); linearly increasing voltage; organic solar cells; photovoltaic cells; photovoltaic power generation; Poisson summation formula; polymers; resistance-dependent photovoltage (RPV); solar cells; solar-photovoltaic energy; superconductivity Publications arising from this thesis are available from the Related URLs field. The delocalized π orbital is the highest occupied molecular orbital (HOMO), and the π* orbital is the lowest unoccupied molecular orbital (LUMO).In organic semiconductor physics, the HOMO takes the role of the valence band while the LUMO serves as the conduction band. The optical absorption coefficient of organic molecules is high, so a large amount of light can be absorbed with a small amount of materials, usually on the order of hundreds of nanometers. Combined with the flexibility of organic molecules, organic solar cells are potentially cost-effective for photovoltaic applications. changing the length and functional group of polymers) can change the band gap, allowing for electronic tunability.When these materials absorb a photon, an excited state is created and confined to a molecule or a region of a polymer chain.The excited state can be regarded as an exciton, or an electron-hole pair bound together by electrostatic interactions.Finally, fractional kinetics and generalised diffusion equations are explored. (2011) Analytic solution of the fractional advection-diffusion equation for the time-of-flight experiment in a finite geometry. We show that the Poisson summation theorem permits the analytic solution of a fractional diffusion equation to be collapsed into closed form. Depending on the band gap of the light-absorbing material, photovoltaic cells can also convert low-energy, infrared (IR) or high-energy, ultraviolet (UV) photons into DC electricity.A common characteristic of both the small molecules and polymers (Fig 1) used as the light-absorbing material in photovoltaics is that they all have large conjugated systems.